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  • 1. Aanes, R
    et al.
    Sæther, B-E
    Smith, F M
    Cooper, E J
    Wookey, Philip
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Miljö- och landskapsdynamik.
    The Arctic Oscillation predicts effects of climate change in the arctic ecosystem2002In: Ecology Letters, Vol. 4, 445-453 p.Article in journal (Refereed)
  • 2.
    Aanes R, Sæther B-E, Smith FM, Cooper EJ, Wookey PA, Øritsland NA
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ENVIRONMENT AND LANDSCAPE DYNAMICS.
    The Arctic Oscillation predicts effects of climate change in two trophic levels in a high-arctic ecosystem2002In: Ecology Letters, ISSN ISSN 1461-023X, Vol. 5, 445-453 p.Article in journal (Refereed)
    Abstract [en]

    During recent decades there has been a change in the circulation of atmospheric pressure throughout the Northern Hemisphere. These variations are expressed in the recently described Arctic Oscillation (AO), which has shown an upward trend (associated with

  • 3. Aaro, Sven
    et al.
    Sjöström, Håkan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Airborne and ground geophysics used for regional tectonic analysis2003In: IUGG 2003, Sapporo, Japan: No GAV.06/10P/A11-004, B260., 2003Conference paper (Refereed)
  • 4.
    Abbas, Khalid
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Processing of full waveform sonic data for shear wave velocity at the Ketzin CO2 storage site2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The accumulation of carbon dioxide gas (CO2) in the atmosphere is considered be the main cause of global warming effects. These emissions can be reduced substantially by capturing and storing the CO2. The CO2SINK project started in April 2004 in the northeast German Basin (NEGB) at the town of Ketzin near Berlin, Germany. Uppsala University is one of the main participants in the seismic part of the CO2SINK project.

    Full waveform sonic data were acquired in the Ktzi-201 injection well at the Ketzin CO2 storage site. The mode of logging was monopole logging. The target was the Stuttgart Formation, a saline sandstone aquifer at the depth of 500-700m. A total of 1210 shots were conducted and data were recorded on 13 channels. Receiver spacing was 6 inches (15.24 cm). The focus of the CO2SINK project was to develop the basis for the CCS technique by injecting CO2 into a saline aquifer and monitoring of the injected CO2 in the aquifer as a pilot study for future geological storage of CO2 in Europe.

    The objective of this study is to calculate P-wave & S-wave velocities from full waveform sonic data recorded in Ktzi-201 injection well. In hard formations, shear wave velocities can be determined directly from full waveform sonic data recorded in monopole logging. However, in slow formations like Stuttgart Formation as in the Ketzin CO2SINK project, shear wave arrivals are absent in full waveform sonic data recorded in monopole logging. In this case, shear wave velocities can be determined from Stoneley wave velocities provided that one knows the P-wave velocity in the borehole fluid.

    P-wave velocities were calculated by picking the P-wave arrivals on full waveform sonic data. Due to the absence of shear wave arrivals, the shear wave velocities were estimated from the larger amplitude Stoneley waves. The estimated S-wave velocities from Stoneley waves were less than the fluid wave velocity in the borehole, confirming the mode of logging was monopole and the formation is a slow formation.

    The reliability of shear wave velocities estimated from Stoneley waves also depends on five other parameters such as formation permeability, borehole fluid property, tool diameter, borehole radius etc.

  • 5.
    Abbott, Benjamin
    et al.
    Univ Rennes 1, OSUR, CNRS, ECOBIO,UMR 6553, Rennes, France.
    Baranov, Viktor
    Leibniz Inst Freshwater Ecol & Inland Fisheries, Berlin, Germany.
    Mendoza-Lera, Clara
    Ctr LyonVilleurbanne, UR MALY, Irstea, F-69616 Villeurbanne, France.
    Nikolakopoulou, Myrto
    Naturalea, Barcelona, Spain.
    Harjung, Astrid
    Univ Barcelona, E-08007 Barcelona, Spain.
    Kolbe, Tamara
    Univ Rennes 1, CNRS, OSURGeosci Rennes, UMR 6118, F-35014 Rennes, France.
    Balasubramanian, Mukundh
    BioSistemika Ltd, Ljubljana, Slovenia.
    Vaessen, Timothy N
    CEAB CSIC, Girona, Spain.
    Ciocca, Francesco
    Silixa, Elstree, England.
    Campeau, Audrey
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Wallin, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Romeijn, Paul
    Univ Birmingham, Sch Geog Earth & Environm Sci, Birmingham B15 2TT, W Midlands, England.
    Antonelli, Marta
    LIST, Esch Sur Alzette, Luxembourg.
    Goncalves, José
    Natl Inst Biol, Ljubljana, Slovenia.
    Datry, Thibault
    Ctr LyonVilleurbanne, UR MALY, Irstea, F-69616 Villeurbanne, France.
    Laverman, Anniet
    Univ Rennes 1, OSUR, CNRS, ECOBIO,UMR 6553, Rennes, France.
    de Dreuzý, Jean-Raynald
    Univ Rennes 1, CNRS, OSURGeosci Rennes, UMR 6118, F-35014 Rennes, France.
    David, Hannah M.
    Univ Birmingham, Sch Geog Earth & Environm Sci, Birmingham B15 2TT, W Midlands, England.
    Krause, Stefan
    Univ Birmingham, Sch Geog Earth & Environm Sci, Birmingham B15 2TT, W Midlands, England.
    Oldham, Carolyn
    Univ Western Australia, Civil Environm & Min Engn, Perth, WA, Australia.
    Pinay, Gilles
    Univ Rennes 1, OSUR, CNRS, ECOBIO,UMR 6553, Rennes, France.
    Using multi-tracer inference to move beyond single-catchment ecohydrology2016In: Earth-Science Reviews, ISSN 0012-8252, E-ISSN 1872-6828, Vol. 160, 19-42 p.Article in journal (Refereed)
    Abstract [en]

    Protecting or restoring aquatic ecosystems in the face of growing anthropogenic pressures requires an understanding of hydrological and biogeochemical functioning across multiple spatial and temporal scales. Recent technological and methodological advances have vastly increased the number and diversity of hydrological, biogeochemical, and ecological tracers available, providing potentially powerful tools to improve understanding of fundamental problems in ecohydrology, notably: 1. Identifying spatially explicit flowpaths, 2. Quantifying water residence time, and 3. Quantifying and localizing biogeochemical transformation. In this review, we synthesize the history of hydrological and biogeochemical theory, summarize modem tracer methods, and discuss how improved understanding of flowpath, residence time, and biogeochemical transformation can help ecohydrology move beyond description of site-specific heterogeneity. We focus on using multiple tracers with contrasting characteristics (crossing proxies) to infer ecosystem functioning across multiple scales. Specifically, we present how crossed proxies could test recent ecohydrological theory, combining the concepts of hotspots and hot moments with the Damkohler number in what we call the HotDam framework.

  • 6.
    Abbott, Benjamin W.
    et al.
    Univ Rennes 1, OSUR, CNRS, UMR ECOBIO 6553, F-35014 Rennes, France.;Univ Alaska Fairbanks, Inst Arctic Biol, Fairbanks, AK USA.;Univ Alaska Fairbanks, Dept Biology& Wildlife, Fairbanks, AK USA..
    Jones, Jeremy B.
    Univ Alaska Fairbanks, Inst Arctic Biol, Fairbanks, AK USA.;Univ Alaska Fairbanks, Dept Biology& Wildlife, Fairbanks, AK USA..
    Schuur, Edward A. G.
    No Arizona Univ, Ctr Ecosyst Sci & Soc, Flagstaff, AZ 86011 USA..
    Chapin, F. Stuart, III
    Univ Alaska Fairbanks, Inst Arctic Biol, Fairbanks, AK USA.;Univ Alaska Fairbanks, Dept Biology& Wildlife, Fairbanks, AK USA..
    Bowden, William B.
    Univ Vermont, Rubenstein Sch Environm & Nat Resources, Burlington, VT 05405 USA..
    Bret-Harte, M. Syndonia
    Univ Alaska Fairbanks, Inst Arctic Biol, Fairbanks, AK USA.;Univ Alaska Fairbanks, Dept Biology& Wildlife, Fairbanks, AK USA..
    Epstein, Howard E.
    Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA..
    Flannigan, Michael D.
    Univ Alberta, Dept Renewable Resources, Edmonton, AB T6G 2M7, Canada..
    Harms, Tamara K.
    Univ Alaska Fairbanks, Inst Arctic Biol, Fairbanks, AK USA.;Univ Alaska Fairbanks, Dept Biology& Wildlife, Fairbanks, AK USA..
    Hollingsworth, Teresa N.
    Univ Alaska Fairbanks, PNW Res Stn, USDA Forest Serv, Fairbanks, AK USA..
    Mack, Michelle C.
    No Arizona Univ, Ctr Ecosyst Sci & Soc, Flagstaff, AZ 86011 USA..
    McGuire, A. David
    Univ Alaska Fairbanks, Alaska Cooperat Fish & Wildlife Res Unit, US Geol Survey, Anchorage, AK USA..
    Natali, Susan M.
    Woods Hole Res Ctr, Woods Hole, MA USA..
    Rocha, Adrian V.
    Univ Notre Dame, Dept Biol Sci, Notre Dame, IN 46556 USA.;Univ Notre Dame, Environm Change Initiat, Notre Dame, IN 46556 USA..
    Tank, Suzanne E.
    Univ Alberta, Dept Biol Sci, Edmonton, AB T6G 2M7, Canada..
    Turetsky, Merritt R.
    Univ Guelph, Dept Integrat Biol, Guelph, ON N1G 2W1, Canada..
    Vonk, Jorien E.
    Vrije Univ Amsterdam, Dept Earth Sci, Amsterdam, Netherlands..
    Wickland, Kimberly P.
    US Geol Survey, Natl Res Program, Boulder, CO USA..
    Aiken, George R.
    US Geol Survey, Natl Res Program, Boulder, CO USA..
    Alexander, Heather D.
    Mississippi State Univ, Forest & Wildlife Res Ctr, Mississippi State, MS 39762 USA..
    Amon, Rainer M. W.
    Texas A&M Univ, Galveston, TX USA..
    Benscoter, Brian W.
    Florida Atlantic Univ, Boca Raton, FL 33431 USA..
    Bergeron, Yves
    Univ Quebec Abitibi Temiscamingue, Forest Res Inst, Rouyn Noranda, PQ, Canada..
    Bishop, Kevin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. wedish Univ Agr Sci, Dept Aquat Sci & Assessment, S-90183 Umea, Sweden..
    Blarquez, Olivier
    Univ Montreal, Dept Geog, Montreal, PQ H3C 3J7, Canada..
    Bond-Lamberty, Ben
    Pacific NW Natl Lab, Richland, WA 99352 USA..
    Breen, Amy L.
    Univ Alaska Fairbanks, Int Arctic Res Ctr, Scenarios Network Alaska & Arctic Planning, Fairbanks, AK USA..
    Buffam, Ishi
    Univ Cincinnati, Cincinnati, OH 45221 USA..
    Cai, Yihua
    Xiamen Univ, State Key Lab Marine Environm Sci, Xiamen, Peoples R China..
    Carcaillet, Christopher
    Ecole Prat Hautes Etud, UMR5023, CNRS Lyon 1, Lyon, France..
    Carey, Sean K.
    McMaster Univ, Hamilton, ON L8S 4L8, Canada..
    Chen, Jing M.
    Univ Toronto, Toronto, ON M5S 1A1, Canada..
    Chen, Han Y. H.
    Lakehead Univ, Fac Nat Resources Management, Thunder Bay, ON P7B 5E1, Canada..
    Christensen, Torben R.
    Lund Univ, Arctic Res Ctr, S-22100 Lund, Sweden.;Aarhus Univ, DK-8000 Aarhus C, Denmark..
    Cooper, Lee W.
    Univ Maryland, Ctr Environm Sci, Bethesda, MD USA..
    Cornelissen, J. Hans C.
    Vrije Univ Amsterdam, Syst Ecol, Amsterdam, Netherlands..
    de Groot, William J.
    Nat Resources Canada, Canadian Forest Serv, Toronto, ON, Canada..
    DeLuca, Thomas H.
    Univ Washington, Sch Environm & Forest Sci, Seattle, WA 98195 USA..
    Dorrepaal, Ellen
    Umea Univ, Dept Ecol & Environm Sci, Climate Impacts Res Ctr, S-90187 Umea, Sweden..
    Fetcher, Ned
    Wilkes Univ, Inst Environm Sci & Sustainabil, Wilkes Barre, PA 18766 USA..
    Finlay, Jacques C.
    Univ Minnesota, Dept Ecol Evolut & Behav, Minneapolis, MN 55455 USA..
    Forbes, Bruce C.
    Univ Lapland, Arctic Ctr, Rovaniemi, Finland..
    French, Nancy H. F.
    Michigan Technol Univ, Michigan Tech Res Inst, Houghton, MI 49931 USA..
    Gauthier, Sylvie
    Nat Resources Canada, Canadian Forest Serv, Laurentian Forestry Ctr, Toronto, ON, Canada..
    Girardin, Martin P.
    Nat Resources Canada, Canadian Forest Serv, Laurentian Forestry Ctr, Toronto, ON, Canada..
    Goetz, Scott J.
    Woods Hole Res Ctr, Woods Hole, MA USA..
    Goldammer, Johann G.
    Max Planck Inst Chem, Global Fire Monitoring Ctr, Berlin, Germany..
    Gough, Laura
    Towson Univ, Dept Biol Sci, Towson, MD USA..
    Grogan, Paul
    Queens Univ, Dept Biol, Kingston, ON K7L 3N6, Canada..
    Guo, Laodong
    Univ Wisconsin Milwaukee, Sch Freshwater Sci, Milwaukee, WI USA..
    Higuera, Philip E.
    Univ Montana, Dept Ecosyst & Conservat Sci, Missoula, MT 59812 USA..
    Hinzman, Larry
    Univ Alaska Fairbanks, Fairbanks, AK USA..
    Hu, Feng Sheng
    Univ Illinois, Dept Plant Biol, Chicago, IL 60680 USA.;Univ Illinois, Dept Geol, Chicago, IL 60680 USA..
    Hugelius, Gustaf
    Stockholm Univ, Dept Phys Geog, Stockholm, Sweden..
    Jafarov, Elchin E.
    Univ Colorado Boulder, Inst Arctic & Alpine Res, Boulder, CO USA..
    Jandt, Randi
    Univ Alaska Fairbanks, Alaska Fire Sci Consortium, Fairbanks, AK USA..
    Johnstone, Jill F.
    Univ Saskatchewan, Dept Biol, Saskatoon, SK S7N 0W0, Canada..
    Karlsson, Jan
    Umea Univ, Dept Ecol & Environm Sci, Climate Impacts Res Ctr, S-90187 Umea, Sweden..
    Kasischke, Eric S.
    Univ Maryland, Dept Geog Sci, Bethesda, MD USA..
    Kattner, Gerhard
    Helmholtz Ctr Polar & Marine Res, Alfred Wegener Inst, Berlin, Germany..
    Kelly, Ryan
    Neptune & Co Inc, North Wales, PA USA..
    Keuper, Frida
    Umea Univ, Dept Ecol & Environm Sci, Climate Impacts Res Ctr, S-90187 Umea, Sweden.;INRA, AgroImpact UPR1158, New York, NY USA..
    Kling, George W.
    Univ Michigan, Ann Arbor, MI 48109 USA..
    Kortelainen, Pirkko
    Finnish Environm Inst, Helsinki, Finland..
    Kouki, Jari
    Univ Eastern Finland, Sch Forest Sci, Joensuu, Finland..
    Kuhry, Peter
    Stockholm Univ, Dept Phys Geog, Stockholm, Sweden..
    Laudon, Hjalmar
    Swedish Univ Agr Sci, Dept Forest Ecol & Management, S-90183 Umea, Sweden..
    Laurion, Isabelle
    Inst Natl Rech Sci, Ctr Eau Terre Environm, Toronto, ON, Canada..
    Macdonald, Robie W.
    Inst Ocean Sci, Dept Fisheries & Oceans, Toronto, ON, Canada..
    Mann, Paul J.
    Northumbria Univ, Dept Geog, Newcastle Upon Tyne NE1 8ST, Tyne & Wear, England..
    Martikainen, Pertti J.
    Univ Eastern Finland, Dept Environm & Biol Sci, Joensuu, Finland..
    McClelland, James W.
    Univ Texas Austin, Inst Marine Sci, Austin, TX 78712 USA..
    Molau, Ulf
    Univ Gothenburg, Dept Biol & Environm Sci, Gothenburg, Sweden..
    Oberbauer, Steven F.
    Florida Int Univ, Dept Biol Sci, Miami, FL 33199 USA..
    Olefeldt, David
    Univ Alberta, Dept Revewable Resources, Edmonton, AB T6G 2M7, Canada..
    Pare, David
    Nat Resources Canada, Canadian Forest Serv, Laurentian Forestry Ctr, Toronto, ON, Canada..
    Parisien, Marc-Andre
    Nat Resources Canada, Canadian Forest Serv, No Forestry Ctr, Toronto, ON, Canada..
    Payette, Serge
    Univ Laval, Ctr Etud Nord, Quebec City, PQ G1K 7P4, Canada..
    Peng, Changhui
    Univ Quebec, Ctr CEF, ESCER, Montreal, PQ H3C 3P8, Canada.;Northwest A&F Univ, Coll Forestry, State Key Lab Soil Eros & Dryland Farming Loess P, Xian, Peoples R China..
    Pokrovsky, Oleg S.
    CNRS, Georesources & Environm, Toulouse, France.;Tomsk State Univ, BIO GEO CLIM Lab, Tomsk, Russia..
    Rastetter, Edward B.
    Marine Biol Lab, Ctr Ecosyst, Woods Hole, MA 02543 USA..
    Raymond, Peter A.
    Yale Univ, Sch Forestry & Environm Studies, New Haven, CT 06520 USA..
    Raynolds, Martha K.
    Univ Alaska Fairbanks, Inst Arctic Biol, Fairbanks, AK USA..
    Rein, Guillermo
    Univ London Imperial Coll Sci Technol & Med, Dept Mech Engn, London SW7 2AZ, England..
    Reynolds, James F.
    Lanzhou Univ, Sch Life Sci, Lanzhou 730000, Peoples R China.;Duke Univ, Nicholas Sch Environm, Durham, NC 27706 USA..
    Robards, Martin
    Arctic Beringia Program, Wildlife Conservat Soc, New York, NY USA..
    Rogers, Brendan M.
    Woods Hole Res Ctr, Woods Hole, MA USA..
    Schaedel, Christina
    No Arizona Univ, Ctr Ecosyst Sci & Soc, Flagstaff, AZ 86011 USA..
    Schaefer, Kevin
    Univ Colorado Boulder, Cooperat Inst Res Environm Sci, Natl Snow & Ice Data Ctr, Boulder, CO USA..
    Schmidt, Inger K.
    Univ Copenhagen, Dept Geosci & Nat Resource Management, DK-1168 Copenhagen, Denmark..
    Shvidenko, Anatoly
    Int Inst Appl Syst Anal, A-2361 Laxenburg, Austria.;Sukachev Inst Forest, Moscow, Russia..
    Sky, Jasper
    Cambridge Ctr Climate Change Res, Cambridge, England..
    Spencer, Robert G. M.
    Florida State Univ, Dept Earth Ocean & Atmospher Sci, Tallahassee, FL 32306 USA..
    Starr, Gregory
    Univ Alabama, Dept Biol Sci, Tuscaloosa, AL 35487 USA..
    Striegl, Robert G.
    US Geol Survey, Natl Res Program, Boulder, CO USA..
    Teisserenc, Roman
    Univ Toulouse, CNRS, INPT, ECOLAB,UPS, Toulouse, France..
    Tranvik, Lars J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Virtanen, Tarmo
    Univ Helsinki, Dept Environm Sci, FIN-00014 Helsinki, Finland..
    Welker, Jeffrey M.
    Univ Alaska Anchorage, Anchorage, AK USA..
    Zimov, Sergei
    Russian Acad Sci, Northeast Sci Stn, Moscow 117901, Russia..
    Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire: an expert assessment2016In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 11, no 3, 034014Article in journal (Refereed)
    Abstract [en]

    As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced.

  • 7. Abbuehl, Luca M.
    et al.
    Norton, Kevin P.
    Schlunegger, Fritz
    Kracht, Oliver
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    El Niño forcing on 10Be-based surface denudation rates in the northwestern Peruvian Andes?2010In: Geomorphology, ISSN 0169-555X, Vol. 123, no 3-4, 257-268 p.Article in journal (Refereed)
    Abstract [en]

    High magnitude precipitation events provide large contributions to landscape formation and surface denudation in arid environments. Here, we quantify the precipitation-dependent geomorphic processes within the Rio Piura drainage basin located on the Western Escarpment of the northern Peruvian Andes at 5 degrees S latitude. In this region, monsoonal easterly winds bring precipitation to the >3000 m asl high headwaters, from where the annual amount of precipitation decreases downstream toward the Pacific coast. Denudation rates are highest in the knickzones near the headwaters, similar to 200-300 mm ky(-1), and sediment discharge is limited by the transport capacity of the channel network. Every few years, this situation is perturbed by westerly, wind-driven heavy precipitation during El Nino events and results in supply-limited sediment discharge as indicated by bedrock channels. The detailed analysis of the stream-long profiles of two river basins within the Rio Piura catchment reveals a distinct knickzone in the transition zone between the easterly and westerly climatic influences, suggesting an En Nino forcing on the longitudinal channel profiles over at least Holocene timescales. Measured trunk stream catchment-wide denudation rates are up to ca. 300 mm ky(-1) and decrease successively downstream along the river profiles. Denudation rates of tributary rivers are ca. 200 mm ky(-1) near the plateau and show a stronger downstream decreasing trend than trunk stream rates. This suggests that the landscape is in a transient stage of local relief growth, which is driven by fluvial incision. This corroborates the results of paleoclimate studies that point towards higher El Nino frequencies during the past ca. 3000 years, leading to higher runoff and more erosion in the trunk channel compared to the hillslopes and thus growth of local relief. Downstream increases in channel gradient spatially coincide with the reaches of highest precipitation rates during El Nino events, we therefore interpret that Holocene landscape evolution has largely been controlled by climate. The ky-timescale of the Be-10 data together with the transience of the landscape implies that El Nino events in northwestern Peru have occurred since at least the Holocene, and that adjustment to channel incision is still taking place.

  • 8. Abbühl, Luca M.
    et al.
    Norton, Kevin P.
    Jansen, John D.
    Schlunegger, Fritz
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Erosion rates and mechanisms of knickzone retreat inferred from (10)Be measured across strong climate gradients on the northern and central Andes Western Escarpment2011In: Earth Surface Processes and Landforms, ISSN 0197-9337, E-ISSN 1096-9837, Vol. 36, no 11, 1464-1473 p.Article in journal (Refereed)
    Abstract [en]

    A steep escarpment edge, deep gorges and distinct knickzones in river profiles characterize the landscape on the Western Escarpment of the Andes between similar to 5 degrees S and similar to 18 degrees S (northern Peru to northern Chile). Strong north-south and east-west precipitation gradients are exploited in order to determine how climate affects denudation rates in three river basins spanning an otherwise relatively uniform geologic and geomorphologic setting. Late Miocene tectonics uplifted the Meseta/Altiplano plateau (similar to 3000 m a.s.l.), which is underlain by a series of Tertiary volcanic-volcanoclastic rocks. Streams on this plateau remain graded to the Late Miocene base level. Below the rim of the Meseta, streams have responded to this ramp uplift by incising deeply into fractured Mesozoic rocks via a series of steep, headward retreating knickzones that grade to the present-day base level defined by the Pacific Ocean. It is found that the Tertiary units on the plateau function as cap-rocks, which aid in the parallel retreat of the sharp escarpment edge and upper knickzone tips. (10)Be-derived catchment denudation rates of the Rio Piura (5 degrees S), Rio Pisco (13 degrees S) and Rio Lluta (18 degrees S) average similar to 10 mm ky(-1) on the Meseta/Altiplano, irrespective of precipitation rates; whereas, downstream of the escarpment edge, denudation rates range from 10 mm ky(-1) to 250 mm ky(-1) and correlate positively with precipitation rates, but show no strong correlation with hillslope angles or channel steepness. These relationships are explained by the presence of a cap-rock and climate-driven fluvial incision that steepens hillslopes to near-threshold conditions. Since escarpment retreat and the precipitation pattern were established at least in the Miocene, it is speculated that the present-day distribution of morphology and denudation rates has probably remained largely unchanged during the past several millions of years as the knickzones have propagated headward into the plateau.

  • 9.
    Abdelrahman, Wedissa
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Reprocessing of reflection seismic data from the Skåne area, southern Sweden2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Seismic reflection surveying is a powerful method to explore the structures of the Earth’s

    crust and describe it is layers. It is also used extensively in the oil industry.

    Offshore seismic profiles were acquired in southern Sweden (Skane area) for petroleum exploration

    purposes, but no productive fields were discovered in that area. The seismic reflection data were

    collected and processed in the 1970s.

    The purpose of this thesis is to reprocess some of the seismic profiles from the 1970s with new

    processing programs to improve the results and compare it with the previous results. Offshore lines

    208, 206, 212 have been selected in this project because they cross each other and are close to a

    borehole with sonic data. The borehole lies close to lines 208 and 212 as seen from the Skane area

    map.

    Also this report can be used to introduce the reader to fundamentals of seismic data processing.

    The processing was done using Claritas software by applying standard processing steps to produce

    migrated stacked sections for every line as a final product.

  • 10.
    Abdetedal, Mahsa
    et al.
    Institute of Geophysics, Tehran, 14155-6466, Iran.
    Shomali, Z. Hossein
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics. Institute of Geophysics, Tehran, 14155-6466, Iran.
    Gheitanchi, Mohammad Reza
    Institute of Geophysics, Tehran, 14155-6466, Iran.
    Ambient noise surface wave tomography of the Makran subduction zone, south-east Iran: Implications for crustal and uppermost mantle structures2015In: Earthquake Science, ISSN 1674-4519, E-ISSN 1867-8777, Vol. 28, no 4, 235-251 p.Article in journal (Refereed)
    Abstract [en]

    Seismic ambient noise of surface wave tomography was applied to estimate Rayleigh wave empirical Green’s functions (EGFs) and then to study crust and uppermost mantle structure beneath the Makran region in south-east Iran. 12 months of continuous data from January 2009 through January 2010, recorded at broadband seismic stations, were analyzed. Group velocities of the fundamental mode Rayleigh wave dispersion curves were obtained from the empirical Green’s functions. Multiple-filter analysis was used to plot group velocity variations at periods from 10 to 50 s. Using group velocity dispersion curves, 1-D v S velocity models were calculated between several station pairs. The final results demonstrate significant agreement to known geological and tectonic features. Our tomography maps display low-velocity anomaly with SW-NE trend, comparable with volcanic arc settings of the Makran region which may be attributable to the geometry of Arabian Plate subducting beneath the overriding the Lut block. The northward subducting Arabian Plate is determined by high-velocity anomaly along the Straits of Hormuz. At short periods (<20 s), there is a sharp transition boundary between low- and high-velocity transition zone with the NW trending at the western edge of Makran which is attributable to the Minab fault system.

  • 11.
    Abdi, Amir
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Re-processing of reflection seismic data from line V2 of the HIRE Seismic Reflection Survey in the Suurikuusikko mining and exploration area, northern Finland2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    The Suurikuusikko gold deposit is located in northern Finland; it is the largest known gold resource in northern Europe. The acquired high resolution reflection seismic data along the c.30 km long profile V2 of the HIRE reflection survey in the Surrikuusikko gold mining and exploration area have been re-processed. A 15.4 ton Geosvip was used as the source, with a receiver spacing of 12.5 m and source spacing of 25 or 50 m. It was aimed to obtain more detailed structural information of the upper 5 – 6 km crust, and to study the seismic response of the important geological and tectonic structures (e.g. Suasselkä PG fault) along the line V2. The line V2 runs from south to north; in the north, it cuts the mafic graphitic tuffic rocks, which are buried under a layer of tholeiite. It is almost perpendicular to the surface trace of the Suasselkä PG fault in the north. The obtained seismic image showed significant improvements compared with the previous work. The seismic response of the major rock units generated strong reflections, and they can be traced down to at least 3 km depth; the reflections correlate well with the surface geology. The moderately dipping reflections from the PG fault are clearly imaged; the dip direction of the fault is towards the SE with a dip of about 50o, possibly decreasing with depth down to about 35o, the fault can be traced down to about 3 km depth. The reverse movement of the fault most probably caused the neighboring sub-horizontal layers to be folded and generated a duplex structure. The dip direction of the major structures in the southern parts is towards NE; this together with the mentioned information about the fault, can be utilized in order to define the major geological structures and most importantly the tectonic evolution of the area; such information can be used in many crucial aspects such as prediction of the future movements of the bedrock and discovery of new resources.

  • 12.
    Abdi, Amir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Heinonen, Suvi
    Juhlin, Christopher
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Karinen, Tuomo
    Constraints on the geometry of the Suasselka post-glacial fault, northern Finland, based on reflection seismic imaging2015In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 649, 130-138 p.Article in journal (Refereed)
    Abstract [en]

    Unloading of the ice during the last glacial period in northern Fennoscandia is believed to have generated major faulting. These faults, often referred to as post-glacial faults, typically have clear surface exposures, but their geometry at depth is poorly known. In order to better understand the geometry at depth of the Suasselka post-glacial fault in Finland, three high resolution 2D reflection seismic profiles over the fault were reprocessed. Their total profile length is about 60 km and they were acquired as part of a major effort in Finland to map the uppermost crust in mining areas. The reprocessing led to significantly improved images that could be used to map the fault at depth. Two approximately N-S striking profiles and one E-W striking profile were reprocessed. The different azimuths and the crooked nature of the profiles allowed the fault geometry to be relatively well constrained. Clear reflections from the fault, dipping towards the SE, can be traced from the shallow subsurface down to about 3 km. The strike and dip of two sets of dipping reflections in the stacked data along with geometrical constraints and cross-dip analysis give a consistent dip of about 35-45 degrees towards the SE for the fault. The strike and dip vary from N55E with a dip of 35 degrees in the east to a strike of N48E with a dip of 45 degrees in the west. Existence of the two sets of reflections indicates that the fault surface is non-planar. Aside from allowing the geometry of the fault to be determined, the seismic data show a complex reflectivity pattern in the area and indications of both reverse and normal movement along fault planes with similar orientation to the Suasselka post-glacial fault. These images can be used as a basis for better characterizing the 3D geology of the area.

  • 13.
    Abdu, Y. A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Annersten, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Ericsson, T.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Hawthorne, F. C.
    High-temperature cation ordering in olivine: an in situ Mossbauer study of synthetic (Mg0.55Fe0.45)(2) SiO42008In: Hyperfine Interactions, ISSN 0304-3843, Vol. 186, no 1-3, 99-103 p.Article in journal (Refereed)
    Abstract [en]

    High- temperature in situ Mossbauer spectroscopy measurements ( 300 950. C) were done on synthetic olivine of composition ( Mg0.55Fe0.45) 2 SiO4 (= Fa45) in order to study the distribution of Fe2+ over the M1 and M2 octahedral sites. The spectra are fit with two doublets, which are assigned to Fe2+ at the M1 ( smaller splitting) and M2 sites. The Fe2+ site- occupancies at M1 and M2, obtained from the Mossbauer relative areas, suggest that Fe2+ has a slight preference for the M1 site at temperatures below similar to 500. C, with a tendency of disordering around this temperature. At higher temperatures, Fe2+ again prefers to occupy the M1 site, where it shows a considerable order at this site up to 750C. At still higher temperatures, the spectra indicated partial reduction of the Fa- component into metallic iron and the resolution of the doublets was severely deteriorated.

  • 14.
    Abdu, Y.A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Ericsson, T
    Annersten, H
    ,, Dubrovinkaja, N.A
    Dubrovinski, L
    Gismelseed, A.M.
    Mössbauer study of the metallic phase of Al Kidirate and new Halfa meteorite2002In: Hyperfine Interaction (C), Vol. 5, 375-378 p.Article in journal (Refereed)
  • 15.
    Abdu, Yassir Ahmed Mohamed
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Mössbauer Spectroscopy of Meteoritic and Synthetic Fe-Ni Alloys2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis reports on the results of investigating Fe-containing minerals in meteorites, with focus on Fe-Ni minerals and their magnetic properties, along with some synthetic Fe-Ni analogues. The New Halfa meteorite, which fell in Sudan 1994, has been studied using Mössbauer spectroscopy, X-ray diffraction, and electron microprobe analysis techniques, and classified as an ordinary L-type chondrite of petrologic type 4. Mössbauer spectra of taenite-enriched samples from the metal particles of the New Halfa (L4) and Al Kidirate (H6) meteorites identify the following γ (fcc) Fe-Ni phases: the ferromagnetic atomically ordered taenite (tetrataenite) with ~ 50 at % Ni, the ferromagnetic disordered taenite with ~ 50 at % Ni, the low-Ni (~ 25 at %) paramagnetic taenite (antitaenite). The presence of the superstructure of tetrataenite is confirmed by synchrotron X-ray diffraction.

    Fe-rich γ (fcc) Fe-Ni alloys with compositions Fe79Ni21, Fe76Ni24, and Fe73Ni27, which serve as synthetic analogues of antitaenite, are prepared by mechanical alloying and subsequent annealing at 650 °C. The Mössbauer results indicate that these alloys are inhomogeneous and contain a high moment (HM) ferromagnetic Ni-rich phase (> 30 at % Ni) and a low moment (LM) paramagnetic Fe-rich phase, which orders antiferromagnetically at low temperature. The coexistence of these phases is attributed to phase segregation occurring on short range, probably nanometer scale, consistent with the Fe-Ni phase diagram below 400 °C where there is a miscibility gap associated with a spinodal decomposition in alloys with < 50 at % Ni.

    The combined high field Mössbauer spectroscopy and SQUID magnetometry results on these alloys at room temperature indicate large induced local magnetic moments in the paramagnetic part of the sample, which increases with increasing the Ni content. The results, when compared with the high field Mössbauer results on antitaenite from the metal particle of Al Kidirate and New Halfa meteorites may be used to estimate the Ni content of antitaenite in meteorites.

    High pressure 57Fe Mössbauer spectroscopy measurements up to ~ 41 GPa have been carried out at room temperature using the diamond anvil cell (DAC) technique in order to investigate the magnetic properties of γ (fcc) 57Fe53Ni47 alloy. The results indicate a pressure induced Invar effect at ~ 7 GPa and a non-magnetic or paramagnetic state above 20 GPa, demonstrating the volume dependence of the magnetic moment of γ (fcc) Fe-Ni alloys.

  • 16.
    Abdu, Yassir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Annersten, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Dubrovinsky, Leonid
    Dubrovinskaia, Natalia
    High pressure Mössbauer studies on fcc Fe53Ni47 alloy2004In: Hyperfine Interactions, ISSN 0304-3843, E-ISSN 1572-9540, Vol. 156, 394- p., 389Article in journal (Refereed)
  • 17.
    Abdu, Yassir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Annersten, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Ericsson, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Field induced local magnetic moments in gamma-fcc Fe-Ni anti-Invar alloys2004In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, Vol. 280, 243-250 p.Article in journal (Refereed)
    Abstract [en]

    Mössbauer spectroscopy in longitudinal external fields (up to 7 T) and SQUID magnetometry (up to 5 T)measurements have been carried out on mechanically alloyed (MA) g (FCC) Fe100xNix (x ¼ 21; 24, and 27 at%) alloysat room temperature. The zero-field M.ossbauer spectra of these alloys show only singlets. The high field M.ossbauerresults indicate that large amounts of the material is in the paramagnetic state, giving rise to two spectral componentswith their effective fields almost linearly depend on the external field, but with slopes that are smaller than unity. The infieldM.ossbauer spectra of the x ¼ 27 at% alloy show an additional component with a hyperfine field of E21 T, whichis attributed to Ni-rich (>30 at% Ni) clusters (domains) of ferromagnetically ordered HM phase that behavessuperparamagnetically at room temperature and shows a non-linear character in the magnetization (M–H) curves atlow fields. This HM phase is also present in the x ¼ 21 and 24 at% samples but with smaller amounts. The resultssuggest induced hyperfine fields and hence induced moments in the paramagnetic components, which increases withincreasing Ni contents. Taenite-enriched samples from the metal particles of two stony meteorites, Al Kidirate (H6)and New Halfa (L4), are also studied by high field M.ossbauer spectroscopy and the results are compared to that ofMA samples.

  • 18.
    Abdu, Yassir
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Ericsson, Tore
    Mössbauer spectroscopy, X-ray diffraction and electron microprobe analysis of the New Halfa meteorite1997In: Meteoritics and Planetary Science, Vol. 32, 373-375 p.Article in journal (Refereed)
  • 19.
    Abdu, Yassir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics III.
    Ericsson, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics III.
    Annersten, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics III.
    Coexisting antiferromagnetism and ferromagnetism in mechanically alloyed Fe-rich Fe-Ni alloys: Implications regarding the Fe-Ni phase diagram below 400 °C2004In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, Vol. 280, no 2-3, 395-403 p.Article in journal (Refereed)
    Abstract [en]

    Fe–Ni alloys below the Invar region with compositions Fe100−xNix (x=21, 24, and 27 at%) were prepared by high-energy ball milling technique (mechanical alloying). The as-milled samples, characterized by X-ray diffraction and Mössbauer spectroscopy, contain a mixture of α (BCC) and γ (FCC) phases, whereas the samples annealed at 650°C for 0.5 h show a single γ (FCC) phase displaying a single line Mössbauer spectrum at room temperature (RT). At low temperature, the Mössbauer spectra of annealed Fe76Ni24 and Fe73Ni27 alloys show the existence of a magnetically split pattern together with a broad singlet, which are ascribed to a high-moment ferromagnetic Ni-rich phase and a low-moment Fe-rich phase, respectively. The Fe-rich phase in annealed Fe76Ni24 alloy, which is paramagnetic at RT, undergoes antiferromagnetic ordering at ∼40 K, estimated from the dramatic line broadening of its spectrum, giving rise to a small hyperfine field (e.g. ∼2 T at 6 K). The coexistence of these phases is attributed to phase segregation occurring in these alloys as a result of enhanced atomic diffusion. The stability of these alloys towards martensitic (FCC→BCC) transformation at low temperatures is discussed in connection with the Fe–Ni phase diagram below 400°C.

  • 20.
    Abdu, Yassir
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Ericsson, Tore
    Annersten, Hans
    Dubrovinskaia, Natalia
    Dubrovinsky, Leonid
    Gismelseed, Abbasher
    Mössbauer studies on the metallic phases of Al Kidirate and New Halfa Meteorites2002In: Hyperfine Interactions C, Vol. 5, 375-378 p.Article in journal (Refereed)
  • 21.
    Abdu, Yassir
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Physics, Department of Physics and Materials Science, Physics III. Technology, Department of Engineering Sciences, Solid State Physics.
    Ericsson, Tore
    Department of Physics. Physics, Department of Physics and Materials Science, Physics III. Technology, Department of Engineering Sciences, Solid State Physics.
    Nordblad, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Physics, Department of Physics and Materials Science, Physics III. Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
    Field-induced local magnetic moments in γ (FCC) Fe-Ni anti –Invar alloys2004In: J. Mag. Mag. Mater, Vol. 280, 243-250 p.Article in journal (Refereed)
  • 22.
    Abeysinghe, Kasun S.
    et al.
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Yang, Xiao-Dong
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China..
    Goodale, Eben
    Guangxi Univ, Coll Forestry, Nanning, Guangxi, Peoples R China..
    Anderson, Christopher W. N.
    Massey Univ, Inst Agr & Environm, Soil & Earth Sci, Palmerston North, New Zealand..
    Bishop, Kevin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    Cao, Axiang
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China.;Guizhou Normal Univ, Sch Chem & Mat Sci, Guiyang, Peoples R China..
    Feng, Xinbin
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China..
    Liu, Shengjie
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Mammides, Christos
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China..
    Meng, Bo
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China..
    Quan, Rui-Chang
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China..
    Sun, Jing
    Nanjing Agr Univ, Coll Resources & Environm Sci, Nanjing, Jiangsu, Peoples R China..
    Qiu, Guangle
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China..
    Total mercury and methylmercury concentrations over a gradient of contamination in earthworms living in rice paddy soil2017In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 36, no 5, 1202-1210 p.Article in journal (Refereed)
    Abstract [en]

    Mercury (Hg) deposited from emissions or from local contamination, can have serious health effects on humans and wildlife. Traditionally, Hg has been seen as a threat to aquatic wildlife, because of its conversion in suboxic conditions into bioavailable methylmercury (MeHg), but it can also threaten contaminated terrestrial ecosystems. In Asia, rice paddies in particular may be sensitive ecosystems. Earthworms are soil-dwelling organisms that have been used as indicators of Hg bioavailability; however, the MeHg concentrations they accumulate in rice paddy environments are not well known. Earthworm and soil samples were collected from rice paddies at progressive distances from abandoned mercury mines in Guizhou, China, and at control sites without a history of Hg mining. Total Hg (THg) and MeHg concentrations declined in soil and earthworms as distance increased from the mines, but the percentage of THg that was MeHg, and the bioaccumulation factors in earthworms, increased over this gradient. This escalation in methylation and the incursion of MeHg into earthworms may be influenced by more acidic soil conditions and higher organic content further from the mines. In areas where the source of Hg is deposition, especially in water-logged and acidic rice paddy soil, earthworms may biomagnify MeHg more than was previously reported. It is emphasized that rice paddy environments affected by acidifying deposition may be widely dispersed throughout Asia.

  • 23.
    Abiodun, B. and Enger, L.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    The role of advection of fluxes on modelling dispersion in convective boundary2002In: Quart. J. Roy. Met. Soc., Vol. 128, 1589-1607 p.Article in journal (Refereed)
  • 24. Abouessa, A.
    et al.
    Morad, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    An integrated study of diagenesis and depositional facies in tidal sandstones: Hawaz Formation (middle Ordovician), Murzuq Basin, Libya2009In: Journal of Petroleum Geology, ISSN 0141-6421, E-ISSN 1747-5457, Vol. 32, no 1, 39-65 p.Article in journal (Refereed)
  • 25.
    Abrahamsson, Elin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Sveriges lantbruksuniversitet.
    In situ-metoder för sanering av klorerade lösningsmedel: utvärdering med avseende på svenska förhållanden2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Currently, there are 428 areas contaminated with chlorinated solvents in Sweden. These substances have been used in Sweden’s industry as degreasing agents and solvents.Chlorinated solvents are more difficult to investigate and remediate compared to petroleum hydrocarbons, due to their complicated distribution in different media. Hence, it is important to increase the knowledge of remediation of chlorinated solvents. The remediation technology excavation is frequently used in Sweden for contaminated areas. Excavation means that soil is dug up and transported to treatment or landfills sites. Due to its climate impact, the use of more sustainable remediation technologies should be increased.

    This thesis aimed to evaluate in situ remediation technologies for soil and groundwater contaminated with chlorinated solvents with respect to functionality, sustainability, time and cost aspects. Furthermore, this thesis aimed to investigate which technologies are best suited for Swedish conditions. To evaluate suitability and functionality of remediation technologies,all technologies were described and a case study of five areas in Sweden contaminated with chlorinated solvents was conducted. The contaminant situation and site-specific conditions were described for each area. Thereafter, the evaluation and choice of remediation technology and remediation result were presented. The technologies studied in the case study were two types of chemical reduction, multi-phase extraction, biostimulation and thermal treatment.The five projects were then assessed using the Swedish Geotechnical Institute’s decision support tool for remediation technologies, SAMLA. The technologies were rated in SAMLA according to criteria related to environmental factors, social factors and costs. Furthermore,the remediation technologies were evaluated based on their strengths and limitations with respect to Swedish conditions, such as geology, climate and geochemistry. They were also evaluated based on their strengths and limitations according to implementation areas, cost,remediation time, energy consumption and use in Sweden.The assessment of the five projects in SAMLA produced similar results compared to previously conducted risk evaluations. The technologies that were chosen based on the risk evaluations were also rated highest in SAMLA. The choice of technology for each project was based on conditions for the area, such as geology and existing buildings. Conclusions were drawn indicating that all technologies can be implemented in Sweden with respect to geological conditions. However, site-specific conditions, such as high groundwater flow and heterogeneous soil, limit the implementation of a specific technology. Moreover, other sitespecific conditions than those already discussed have to be considered, for instance buildings or future exploitation. Future development of in situ remediation technologies may focus on implementation of a certain type of geology (highly permeable soils), where chlorinated solvents may be found more frequently.

  • 26.
    Abrahamsson, Elin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Ekelund, My
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Human Exposure from Mercury in Rice in the Philippines2015Student paper other, 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the western part of the Philippines, in the Palawan province, studies have shown that large quantities of mercury are spread to the surrounding area during heavy rainfall. In addition, mercury is spread to rice fields and bioaccumulated in marine fish and seafood. The mercury originates from the abandoned Palawan Quicksilver Mine. Since mercury is toxic for the human body and new studies have shown that mercury accumulates in rice, it is important to investigate human exposure from mercury in rice.

    This project investigates the total amount of mercury and methylmercury (MeHg) accumulated in rice, soil and water from four different rice fields in Palawan. The soil samples have been taken directly from the fields and water samples have been taken from nearby streams and springs. Rice grains harvested earlier this year from the same fields have been collected from farmers. The soil, water and rice samples were analyzed in Manila and rice samples were as well analyzed in Sweden and China. Furthermore, this project contains a dietary survey and calculation of daily exposure values of MeHg. The survey investigates how often people eat fish and rice and if they have dental amalgam. It also investigates possible health problems related to mercury exposure from rice and fish consumption.

    The analyses from China show that rice samples from all barangays contain total mercury and MeHg. Analyses from Sweden also show that rice from the barangays contains total mercury but the levels were found to be higher than the ones analyzed in China. Furthermore, the health problems found in the diet survey were hard to relate to mercury exposure from rice since the health problems can be caused by other factors. When calculating daily exposure values, the values were found to be as high as the recommended maximum acceptable daily intake in one of the barangays. There might therefore be a risk of eating rice from these four barangays. It is important to consider that these daily exposure values were only based on MeHg exposure from rice consumption, not taking dental amalgam and fish consumption into consideration. This means that the daily exposure values might be even higher than the ones calculated in this study.

  • 27.
    Abrahamsson, Kristina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Bachofner Gran, Clara
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    de Afonseca, Ana
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Eriksson, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Kalla, Christelle
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Lindqvist, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Livscykelanalys av förbrukningsvaror: En studie för minskad klimatpåverkan inom Landstinget i Uppsala län2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Landstinget i Uppsala län (LUL) presenterade år 2014 ett miljöprogram med målet att minskasin klimatpåverkan inom bland annat transport, energi och förbrukningsmaterial. Syftet meddenna studie var att undersöka möjligheten för LUL att minska sina utsläpp av växthusgasergenom att välja mer miljövänliga varianter av två välanvända förbrukningsvaror inom vården:operationsset och tvättlappar. Detta utfördes genom att tillämpa metoden livscykelanalys(LCA), där tre varianter av operationsset, två sorters tvättlappar samt ett jämförbartavtorkningspapper följdes ”från vaggan till graven”.Studiens resultat skulle besvara frågan om vilken produkt inom de två användningsområdenasom avgav minst växthusgaser i form av koldioxid, metan samt lustgas under en livscykel, föratt uppfylla samma funktion inom avdelningarna operation samt geriatrik. Resultatet skullepresenteras i enheten koldioxidekvivalenter (eCO2). Dessutom identifieradesförbrukningsvarorna som medförde de minsta årsförbrukningskostnaderna för LUL.Operationsseten som undersöktes bestod av polylaktid (PLA), polypropen (PP) samt viskos.Avtorkningspappret bestod av pappersmassa och tvättlapparna bestod bland annat av viskossamt skumplast. Studien avgränsades till att inkludera växthusgasutsläpp från tillverkning avråmaterial, tillverkning av förpackningsmaterial, transporter samt förbränning.Efter utförd LCA kunde det observeras att en årsförbrukning av operationssetet i PLA släppteut minst växthusgaser med cirka 11 100 kg eCO2 per år, operationssetet i PP släppte ut mestmed 25 100 kg eCO2 per år och operationssetet i viskos bidrog med 20 300 kg eCO2 per år. Enårsförbrukning av avtorkningspappret bidrog med minst växthusgasutsläpp med 67,1 kg eCO2per år, medan tvättlappen i viskos släppte ut 134 kg eCO2 per år och tvättlappen i skumplastbidrog med det största utsläppsvärdet på 1 150 kg eCO2 per år.En årsförbrukning av båda operationsseten i PLA och PP kostade cirka 127 000 kr medansamma mängd av operationssetet i viskos ungefär kostade 125 000 kr. Avtorkningspappretkostade 4 790 kr för en årsförbrukning, tvättlappen i viskos kostade 21 000 kr och tvättlappeni skumplast kostade 19 800 kr.Resultatet från denna studie tydde på att LUL skulle kunna minska sin klimatpåverkan frånförbrukningsmaterial genom att upphandla operationssetet i PLA samt avtorkningspappretistället för de alternativen som används i dagsläget. Det finns en osäkerhet i resultatet då flertaletantaganden gjordes i brist på tillgänglig information. Resultatet anses dock ge en rimlig bild avmiljöpåverkan från produkterna då de minst klimatpåverkande förbrukningsvarorna till stor delutgjordes av förnyelsebart material.

  • 28.
    Abrahamsson, Otto
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Håkanson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Modelling seasonal flow variability of European rivers1998In: Ecological Modelling, ISSN 0304-3800, Vol. 114, no 1, 49-58 p.Article in journal (Refereed)
    Abstract [en]

    River discharge influences many important processes in a lake ecosystem. For example, the tributary discharge is one of the major regulating factors for the lake water retention time and, hence, the retention of substances in lake water. However, river discharge depends on many more or less stochastic processes, which makes it difficult to give a reliable prediction of the discharge for a specific river at a given time. This paper presents an attempt to overcome many of those difficulties with a simple mathematical model. The model was designed to meet some specific demands for ecosystem modelling of contaminating substances. The most important of those requirements is that the model had to be based on readily available driving variables, preferably from standard maps. The presented results are based on extensive calibrations and validations using empirical data on monthly water discharge from more than 200 European rivers. It may be concluded that this model yields predictions that capture the essential components in mean monthly variations in river discharge in European rivers and that this model is driven by easily available driving variables like catchment area, mean annual precipitation, altitude, and latitude. The technique to obtain seasonal variability is based on calibrated ‘norms’ and smoothing functions defined from the driving variables.

  • 29.
    Abrahamsson, Otto
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Håkanson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Presentation and analysis of a model simulating the response of potash treatment of lakes1997In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 37, no 3, 287-306 p.Article in journal (Refereed)
    Abstract [en]

    The potassium concentration in a lake may influence the caesium levels in lake biota. The biouptake and potential ecosystem effects of a caesium fall-out can be limited by addition of potassium, for example, by a potash treatment. This work presents for the first time a simple and practically useful model to facilitate the planning and to predict the outcome of potash treatments by simulating the processes that regulate the water chemical response of such a treatment. The model is a mixed model in the sense that it contains both statistical regressions and dynamic interactions within a lake ecosystem. This paper focuses on the dynamic processes and gives both calibrations and extensive validations of the model. A few examples on the practical use of the model are presented. The results indicate that the model, using only easily accessible input data, can, in fact, give good predictions on the increase and duration in potassium concentration following a potash treatment.

  • 30.
    Abtahi, Sayyed Mohammad
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Airborne Gravity Gradient, Magnetic and VLF datasets: Case studies of modelling, inversion and interpretation2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Northern Sweden is one of the largest hosts for mineral resources in Europe and always has been an interesting area for researchers from various disciplines of Earth sciences. This dissertation is a comprehensive summary of three case study papers on airborne VLF, gravity gradient and magnetic data in the area.

    In the first paper, tensor VLF data is extracted from an old data set which contains only the total and the vertical magnetic components. The anomalous part of the horizontal magnetic field components is computed by a Hilbert transform of the vertical magnetic field. The normal part of the horizontal magnetic field component is computed as a function of total, vertical and anomalous part of horizontal magnetic fields. The electric field is also calculated for TE mode and impedance tensor and apparent resistivity are computed. In addition tippers are calculated for two transmitters and inverted by a 3D inversion algorithm. Comparison of the estimated model and geology map of bedrock shows that lower resistivity zones are correlated with mineralizations.

    The second paper deals with the internal consistency of airborne gravity gradient data. The six components of the data are estimated from a common potential function. It is shown that the data is adequately consistent but at shorter land clearances the difference between the estimated data and the original data is larger. The technique is also used for computing the Bouguer anomaly from terrain corrected FTG data. Finally the data is inverted in 3D, which shows that the estimated density model in shallow depth is dominated by short wave length features.

    Inversion of TMI data is the topic of the third paper where a new type of reference model for 3D inversion of magnetic data is proposed by vertically extending the estimated magnetization of a 2D terrain magnetization model. The final estimated 3D result is compared with the magnetization model where no reference model is used. The comparison shows that using the reference model helps the high magnetization zones in the estimated model at shallow depths to be better correlated with measured high remanent magnetization from rock samples. The high magnetization zones are also correlated with gabbros and volcanic metasediments.

  • 31.
    Abtahi, Sayyed Mohammad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics. Isfahan Univ Technol, Dept Min Engn, Esfahan, Iran.
    Pedersen, Laust
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Kamm, Jochen
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Kalscheuer, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Consistency investigation, vertical gravity estimation and inversion of airborne gravity gradient data – A case study from northern Sweden2016In: Geophysics, ISSN 0016-8033, E-ISSN 1942-2156, Vol. 81, no 3, B65-B76 p.Article in journal (Refereed)
    Abstract [en]

    For airborne gravity gradient data, it is a challenge to distinguish between high-frequency intrinsic and dynamically produced noise caused by the aircraft and small-scale effects from shallow density variations. To facilitate consistent interpretation, techniques that include all of the measured gravity gradient components are particularly promising. We represented the measurements by a common potential function accounting for lateral and height variations. Thus, it was possible to evaluate the internal consistency between the measured components and to identify components with bias or particularly strong noise. As an extra benefit for data sets that contain terrain-corrected and nonterrain-corrected gravity gradient measurements at flight altitude, we estimated terrain-corrected anomalies on the topographic relief using downward continuation and retrieved nonterrain-corrected gravity gradient data suitable for inversion using upward continuation. For a field data set from northern Sweden, the largest differences (up to 50 eotvos) between the measured and estimated components of the gravity gradient data were found in areas of high topographical relief. But the average residual standard deviations of the individual components were between 3.6 and 7.4 eotvos, indicating that the components were consistent in an average sense. We have determined the successful conversion of terrain-corrected airborne gravity gradient data to Bouguer gravity data on the topographic relief using ground-based vertical gravity data as a reference. A 3D inverse model computed from the nonterrain-corrected data clearly showed the depth extent of the geologic structures observed at the surface, but it only produced a weak representation of the shallow structure. In contrast, a 2D surface density model in which only lateral variations of density in the topographic relief was allowed exhibited more realistic density distributions in fair correlation with geology.

  • 32.
    Abtahi, Sayyed Mohammad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics. Isfahan Univ Technol, Dept Min Engn, Esfahan, Iran.
    Pedersen, Laust
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Kamm, Jochen
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics. Univ Munster, Dept Geophys, Munster, Germany.
    Kalscheuer, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Extracting geoelectrical maps from vintage very-low-frequency airborne data, tipper inversion, and interpretation: A case study from northern Sweden2016In: Geophysics, ISSN 0016-8033, E-ISSN 1942-2156, Vol. 81, no 5, B135-B147 p.Article in journal (Refereed)
    Abstract [en]

    In 1985, the mining company Luossavaara-Kiirunavaara Aktiebolag collected airborne very-low-frequency (VLF) data in northern Sweden. The operators stored only the vertical component and the total magnetic field, which at that time were believed to be sufficient for qualitative interpretation. Therefore, the data could not be directly used for quantitative tensor VLF processing and inversion. To avoid the costs of resurveying, we have developed a novel technique to estimate the tippers from the measured VLF data by computing anomalous and normal parts of the horizontal components of the magnetic field from two transmitters separately. Retrieval of the normal horizontal components was possible because one component of the horizontal magnetic field was used as the phase reference during the measurements. Additionally, we have determined how the approximate apparent resistivity suitable for data visualization can be computed from the components of the magnetic field assuming an average normal resistivity of the subsurface. Maps of apparent resistivity combined with topography show a clear correlation between high topography and high resistivity, whereas conductive zones are found in valleys in between. More importantly, the 3D model inverted from the calculated tippers shows excellent agreement with a map of the surface geology. Based on this comparison, some less resistive zones can be related to fluids in fractures and others can be related to mineralized contact zones. We suggest to focus further exploration on conductive zones surrounding areas with basaltic composition.

  • 33. Aburto, J.
    et al.
    Gallardo, Gloria
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Uppsala Centre for Sustainable Development, CSD Uppsala.
    Stotz, W.
    Cerda, C.
    Mondaca-Schachermayer, C.
    Vera, K.
    Territorial user rights for artisanal fisheries in Chile: intended and unintended outcomes2013In: Ocean and Coastal Management, ISSN 0964-5691, Vol. 71, 284-295 p.Article in journal (Refereed)
    Abstract [en]

    Granting property property rights in fisheries is assumed to provide incentives for sustainable resource exploitation. These rights might also open other income options for fishers, including some that go beyond the original objectives intended by authorities establishing the right. The opportunity for alternative uses is especially high if the details of these rights are not clearly identified. In Chile, a de novo TURF (Territorial User Rights for Fishery) system, called Management Exploitation Areas for Benthic Resources (Areas de Manejo y Explotacion de Recursos Bentonicos-AMERB) was created to achieve sustainable exploitation of benthic resources. This study compares two small-scale fishing communities in Chile, Guayacan and Huentelauquen, representing two typical contrasting settings, regarding geographical contexts and surroundings, origin, history, location, social embeddedness, main fisheries activities as well as the motivation and the process through which they acquired their AMERB. While in Guayacan the main fishing activity outside the AMERB is the giant squid and finfish fishery, in Huentelauquen the main and traditional activity has been diving for benthic resources. The objectives to acquire their AMERBs were different in both cases. Huentelauquen applied the AMERB for their traditional activity, the fishery of Concholepas concholepas ("loco"), thus in accordance with the official objective of the AMERB. Due to reduced catches of loco, fishers also added the collection of kelps, using their AMERB to control access to the entire coast surrounding their fishing community, beyond the limits of their AMERB. In Guayacan the AMERB, applied for the management of scallops and a species of red algae, began to be used for sea squirt aquaculture. Within the framework of sustainable fisheries implied by the AMERBs, there was in both cases a clear expectation to gain new sources of income. However with time both AMERBs are being used as a tool for territorial exclusion of other fishers beyond the limits of their respective AMERBs. In Huentelauquen fishers mention mostly negative aspects about the performance of their AMERB, given the poor economic results, being unsatisfied with the AMERB system in general, because they feel that the system disrupted their traditional migration along the coast. In Guayacan, fishers mentioned mostly positive aspects for their AMERB, as it was an opportunity to add new activities. Both examples show that rights-based management approaches are very attractive; they could promote new uses or developments, whose sustainability nevertheless needs to be analyzed further. The analyzed case studies show that, contrary to how the system was developed in Chile, a more bottom-up implementation of new management arrangements may make it easier to agree on common objectives, and/or leave more freedom for fishers to adjust and arrange their livelihood. Considering the importance the AMERBs have acquired for fishers, these kinds of systems need flexible regulations in order that fishers can adapt the system to local traditions, uses or needs and also to their learning and adapting capacities.

  • 34.
    Acikkol, Naz
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Testing the Cretaceous Diversity of Ichthyosaurs and Their Extinction Hypotheses Using a Quantitative Approach2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As portrayed in Before the Dinosaur: the Historical Significance of the Fossil Marine Reptiles, ichthyosaurs, as other Mesozoic marine amniotes, have been unfairly overshadowed by dinosaurs in both popular culture and the field of vertebrate palaeontology. Yet by the effort of dedicated researchers, work on these fish-like marine reptiles had never died out, and in fact a second wave of interest emerged in the late 20th century. Since then, research on ichthyosaurs has focused on discovery of new taxa, assessments of their palaeobiology, and quantitative analyses of their diversity. Despite ever-growing interests, patterns and mechanisms leading up to their extinction in the Cenomanian were insufficiently evaluated. In other words, hypotheses focusing on abrupt extinction linked to a crash in prey diversity, notably belemnites, over a catastrophic event at the end-Cenomanian remain poorly tested. The current project thus aims to test: 1) whether the Cretaceous diversity of ichthyosaurs reflects biological signals, and 2) correlation of their diversity with the diversity of Mesozoic cephalopods, such as belemnites and ammonites. In this regard, a species-level dataset of Cretaceous belemnites including belemnite-bearing formations was built to be employed together with the occurrence-based ichthyosaur and ammonite datasets in the same taxic level. Raw taxic counts, as observed diversities of the clades, were quantified in two different temporal scales, and compared with two sampling proxies. The model-based method was then applied to correct all taxic counts based on the two proxies in both time bins to acquire expected diversities of all the clades. Comparisons resulted in strong correlations between the clades’ observed diversities and proxies exposing biased patterns under the influence of sampling intensity. Whereas both observed and expected diversities show no evidence of a causal relationship between the predator and prey groups, suggesting that the latter’s diversity seems not being a parameter for the former’s, and thus being unsupportive for a prey-driven demise of the predator. Furthermore, the expected trend of ichthyosaurs indicates lower Albian diversity gradually declining towards their extinction in the Cenomanian, which appears to be contrasting with recent studies.

  • 35.
    Acocella, V.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Mulugeta, G.
    Experiments simulating surface deformation induced pluton emplacement.2002In: Tectonophysics, Vol. 352, 275-293 p.Article in journal (Refereed)
  • 36.
    Acocella, V
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Mulugeta, G
    Surface deformation induced by pluton emplacement: The case of Amiata (Italy)2001In: PHYSICS AND CHEMISTRY OF THE EARTH PART A-SOLID EARTH AND GEODESY, ISSN 1464-1895, Vol. 26, no 4-5, 355-362 p.Article in journal (Refereed)
    Abstract [en]

    The Amiata area was uplifted during the Pliocene as a consequence of pluton emplacement in an extensional setting. In the Middle Pleistocene, a fissural eruption filled a depression within the uplifted area. Field analysis and analogue models are integrat

  • 37.
    Adamaki, Angeliki
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Seismicity Analyses Using Dense Network Data: Catalogue Statistics and Possible Foreshocks Investigated Using Empirical and Synthetic Data2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Precursors related to seismicity patterns are probably the most promising phenomena for short-term earthquake forecasting, although it remains unclear if such forecasting is possible. Foreshock activity has often been recorded but its possible use as indicator of coming larger events is still debated due to the limited number of unambiguously observed foreshocks. Seismicity data which is inadequate in volume or character might be one of the reasons foreshocks cannot easily be identified. One method used to investigate the possible presence of generic seismicity behavior preceding larger events is the aggregation of seismicity series. Sequences preceding mainshocks chosen from empirical data are superimposed, revealing an increasing average seismicity rate prior to the mainshocks. Such an increase could result from the tendency of seismicity to cluster in space and time, thus the observed patterns could be of limited predictive value. Randomized tests using the empirical catalogues imply that the observed increasing rate is statistically significant compared to an increase due to simple clustering, indicating the existence of genuine foreshocks, somehow mechanically related to their mainshocks. If network sensitivity increases, the identification of foreshocks as such may improve. The possibility of improved identification of foreshock sequences is tested using synthetic data, produced with specific assumptions about the earthquake process. Complications related to background activity and aftershock production are investigated numerically, in generalized cases and in data-based scenarios. Catalogues including smaller, and thereby more, earthquakes can probably contribute to better understanding the earthquake processes and to the future of earthquake forecasting. An important aspect in such seismicity studies is the correct estimation of the empirical catalogue properties, including the magnitude of completeness (Mc) and the b-value. The potential influence of errors in the reported magnitudes in an earthquake catalogue on the estimation of Mc and b-value is investigated using synthetic magnitude catalogues, contaminated with Gaussian error. The effectiveness of different algorithms for Mc and b-value estimation are discussed. The sample size and the error level seem to affect the estimation of b-value, with implications for the reliability of the assessment of the future rate of large events and thus of seismic hazard.

  • 38.
    Adamaki, Angeliki K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Roberts, Roland G.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Precursory Activity Before Larger Events in Greece Revealed by Aggregated Seismicity Data2017In: Pure and Applied Geophysics, ISSN 0033-4553, E-ISSN 1420-9136, Vol. 174, no 3, 1331-1343 p.Article in journal (Refereed)
    Abstract [en]

    We investigate the seismicity rate behaviour in and around Greece during 2009, seeking significant changes in rate preceding larger events. For individual larger events it is difficult to clearly distinguish precursory rate changes from other, possibly unrelated, variations in seismicity. However, when we aggregate seismicity data occurring within a radius of 10 km and in a 50-day window prior to earthquakes with, e. g. magnitude C3.5, the resulting aggregated time series show a clearly increasing trend starting 2-3 weeks prior to the "mainshock'' time. We apply statistical tests to investigate if the observed behaviour may be simply consistent with random (poissonian) variations, or, as some earlier studies suggest, with clustering in the sense that high activity rates at some time may imply increased rates later, and thus (randomly) greater probability of larger coming events than for periods of lower seismicity. In this case, rate increases have little useful predictive power. Using data from the entire catalogue, the aggregated rate changes before larger events are clearly and strongly statistically significant and cannot be explained by such clustering. To test this we choose events at random from the catalogue as potential "mainshocks''. The events preceding the randomly chosen earthquakes show less pronounced rate increases compared to the observed rate changes prior to larger events. Similar behaviour is observed in data sub-sets. However, statistical confidence decreases for geographical subsets containing few "mainshocks'' as it does when data are weighted such that "mainshocks'' with many preceding events are strongly downweighted relative to those with fewer. The analyses suggest that genuine changes in aggregated rate do occur prior to larger events and that this behaviour is not due to a small number of mainshocks with many preceding events dominating the analysis. It does not automatically follow that it will be possible to routinely observe precursory changes prior to individual larger events, but there is a possibility that this may be feasible, e. g. with better data from more sensitive networks.

  • 39.
    Adamaki, Angeliki
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Roberts, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Advantages and Limitations of Foreshock Activity as a Useful Tool for Earthquake ForecastingManuscript (preprint) (Other academic)
  • 40.
    Adamaki, Angeliki
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Roberts, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    EVIDENCE OF PRECURSORY PATTERNS IN AGGREGATED TIME SERIES2016In: Bulletin of the Geological Society of Greece, vol. L, 2016, Proceedings of the 14th Intern. Congress, Thessaloniki, May 2016, 2016, Vol. 50Conference paper (Refereed)
    Abstract [en]

    We investigate temporal changes in seismic activity observed in the West Corinth Gulfand North-West Peloponnese during 2008 to 2010. Two major earthquake sequencestook place in the area at that time (in 2008 and 2010). Our aim is to analyse Greekseismicity to attempt to confirm the existence or non-existence of seismic precursorsprior to the strongest earthquakes. Perhaps because the area is geologically andtectonically complex, we found that it was not possible to fit the data well using aconsistent Epidemic Type Aftershock Sequence (ETAS) model. Nor could weunambiguously identify foreshocks to individual mainshocks. Therefore we soughtpatterns in aggregated foreshock catalogues. We set a magnitude threshold (M3.5)above which all the earthquakes detected in the study area are considered as“mainshocks”, and we combined all data preceding these into a single foreshockcatalogue. This reveals an increase in seismicity rate not robustly observable forindividual cases. The observed effect is significantly greater than that consistent withstochastic models, including ETAS, thus indicating genuine foreshock activity withpotential useful precursory power, if sufficient data is available, i.e. if the magnitudeof completeness is sufficiently low.

  • 41. Adamczyk, A.
    et al.
    Malinowski, M.
    Malehmir, Alireza
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    High-resolution near-surface velocity model building using full-waveform inversion-a case study from southwest Sweden2014In: Geophysical Journal International, ISSN 0956-540X, E-ISSN 1365-246X, Vol. 197, no 3, 1693-1704 p.Article in journal (Refereed)
    Abstract [en]

    Full-waveform inversion (FWI) is an iterative optimization technique that provides high-resolution models of subsurface properties. Frequency-domain, acoustic FWI was applied to seismic data acquired over a known quick-clay landslide scar in southwest Sweden. We inverted data from three 2-D seismic profiles, 261-572 m long, two of them shot with small charges of dynamite and one with a sledgehammer. To our best knowledge this is the first published application of FWI to sledgehammer data. Both sources provided data suitable for waveform inversion, the sledgehammer data containing even wider frequency spectrum. Inversion was performed for frequency groups between 27.5 and 43.1 Hz for the explosive data and 27.5-51.0 Hz for the sledgehammer. The lowest inverted frequency was limited by the resonance frequency of the standard 28-Hz geophones used in the survey. High-velocity granitic bedrock in the area is undulated and very shallow (15-100 m below the surface), and exhibits a large P-wave velocity contrast to the overlying normally consolidated sediments. In order to mitigate the non-linearity of the inverse problem we designed a multiscale layer-stripping inversion strategy. Obtained P-wave velocity models allowed to delineate the top of the bedrock and revealed distinct layers within the overlying sediments of clays and coarse-grained materials. Models were verified in an extensive set of validating procedures and used for pre-stack depth migration, which confirmed their robustness.

  • 42. Adamczyk, Anna
    et al.
    Malinowski, Michal
    Malehmir, Alireza
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Application of first-arrival tomography to characterize a quick clay landslide site in Southwest Sweden2013In: Acta Geophysica, ISSN 1895-6572, Vol. 61, no 5, 1057-1073 p.Article in journal (Refereed)
    Abstract [en]

    First-arrival traveltime tomography was applied to high-resolution seismic data acquired over a known quick-clay landslide scar near the Gota River in southwest Sweden in order to reveal the geometry and physical properties of clay-related normally consolidated sediments. Investigated area proved to be a challenging environment for tomographic imaging because of large P-wave velocity variations, ranging from 500 to 6000 m/s, and relatively steeply-dipping bedrock. Despite these challenges, P-wave velocity models were obtained down to ca. 150 m for two key 2D seismic profiles (each about 500-m long) intersecting over the landslide scar. The models portrait the sandwich-like structure of marine clays and coarse-grained consolidated sediments, but the estimated resolution (20 m) is too small to distinguish thin layers within this structure. Modelled velocity structures match well the results of reflection seismic processing and resistivity tomography available along the same profiles.

  • 43.
    Adamczyk, Anna
    et al.
    Institute of Geophysics - Polish Academy of Sciences.
    Malinowski, Michal
    Institute of Geophysics - Polish Academy of Sciences.
    Malehmir, Alireza
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Delineating shallow quick-clay structures using acoustic full-waveform inversion – case studyfrom southwest Sweden2013Conference paper (Refereed)
    Abstract [en]

    Full waveform inversion (FWI) was applied to imageshallow structures of marine-clay sediments and to provideinsight on the mechanism of a quick-clay landslide. Thedata was acquired in a high-resolution seismic surveyconducted over a known landslide scar near the Göta riverin southwest Sweden. Inversion proved to be challengingbecause of contrasted P-wave velocity structure – thevelocities ranged from 500 m/s in weathered top layer to6000 m/s in the shallow granitic bedrock (up to 30 m belowthe surface). FWI applied to 3 profiles provided highresolution2D P-wave velocity models revealing theintercalating layers of clays and coarse-grain material andthe shape of the bedrock. The multiscale approach was usedto mitigate the strong nonlinearity of the inverse problem.The models were used in pre-stack depth migration andproved significant improvement in reflector flattening andfocusing over the starting first-arrival traveltimetomography models.

  • 44.
    Adamoski, Michele
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Wast Management System for Western Africa: Analysis of systemssuccessfully applied in the world that may fit the reality faced in Western Africa2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Health and safety have been the most important concerns in waste management formany years. However, nowadays society demands that as well as being safe, waste managementmust also be sustainable. The management of a sustainable Municipal Solid Waste is anecessary but not-prioritized aspect of environmental management in most countries with lowand middle income.This study purposes an analysis of technologies, in order to select the best and mostsuitable practices in Sustainable Waste Management Systems already applied or in advancedlevel of research in developed and developing countries. The target countries for receiving thisstudy of waste system are located in Western Africa: Ghana, Côte d‟Ivoire, Senegal andNigeria.The analysis of collection, transportation, treatment and disposal of waste, with focus onorganic matter, was presented in two groups. The first group, “collection and transportation”was analysed with attention to aspects and stakeholders presented in the Integrated SustainableWaste Management framework. In the second group, “treatment and disposal”, each technologywas analysed based on aspects of sustainable development. The decision-support software Web-HIPRE was also used to frame the final rank of solutions for the African scenario.The conclusions for those analyses were that the creation of micro and small enterprisesand community based organizations for collection and transportation should strongly beencouraged. They generate not just new employment but awareness among the population aswell. As for the treatment and disposal of organic household waste, two promising technologiesare decentralized composting and home composting with plastic bins.

  • 45.
    Adamsson, Karolin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Kollektivtrafikknutpunkter i Göteborg ur ett genusperspektiv2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper will examine two public transportation hubs, as examples of public space, in Gothenburg, Sweden, from a gender perspective by investigate how gender equality is discussed in planning processes of hubs and to explore how hubs are used and perceived by men and women. The thesis has a qualitative and hermeneutic approach, with semi-structured interviews with key persons from the planning processes, and site observations and interviews with men and women using the hubs as the main data gathering methods. In the planning processes for the two cases the ambition was to create hubs that were welcoming for everyone, from a theoretical point of view this ambition could be dangerous from a gender perspective since a planning for everyone often leads to a planning for the man. In order to create hubs for everyone there was a focus for creating safety and increase accessibility for the disabled during the planning processes. The observations and the interviews on site shows that the hubs could be viewed as gender equal since the hubs were open to both men and women to use, but the hubs could also be viewed as not gender equal since women felt unsafe. The analysis shows that the social interaction on site is a crucial factor when defining a place as gender equal or not. The social interaction can be understood by gender contract. One conclusion is that there is a need for discussions about gender and its effect on experiences of public space, where gender contract is problematized. It will otherwise be hard to understand and change the interaction and the gender inequality will risk to consolidate.

  • 46.
    Addor, Nans
    et al.
    Univ Zurich, Dept Geog, Zurich, Switzerland.;Natl Ctr Atmospher Res, Appl Res Lab, POB 3000, Boulder, CO 80307 USA..
    Rohrer, Marco
    Univ Bern, Oeschger Ctr Climate Change Res, Bern, Switzerland.;Univ Bern, Inst Geog, Bern, Switzerland..
    Furrer, Reinhard
    Univ Zurich, Dept Math, Zurich, Switzerland..
    Seibert, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Univ Zurich, Dept Geog, Zurich, Switzerland..
    Propagation of biases in climate models from the synoptic to the regional scale: Implications for bias adjustment2016In: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 121, no 5, 2075-2089 p.Article in journal (Refereed)
    Abstract [en]

    Bias adjustment methods usually do not account for the origins of biases in climate models and instead perform empirical adjustments. Biases in the synoptic circulation are for instance often overlooked when postprocessing regional climate model (RCM) simulations driven by general circulation models (GCMs). Yet considering atmospheric circulation helps to establish links between the synoptic and the regional scale, and thereby provides insights into the physical processes leading to RCM biases. Here we investigate how synoptic circulation biases impact regional climate simulations and influence our ability to mitigate biases in precipitation and temperature using quantile mapping. We considered 20 GCM-RCM combinations from the ENSEMBLES project and characterized the dominant atmospheric flow over the Alpine domain using circulation types. We report in particular a systematic overestimation of the frequency of westerly flow in winter. We show that it contributes to the generalized overestimation of winter precipitation over Switzerland, and this wet regional bias can be reduced by improving the simulation of synoptic circulation. We also demonstrate that statistical bias adjustment relying on quantile mapping is sensitive to circulation biases, which leads to residual errors in the postprocessed time series. Overall, decomposing GCM-RCM time series using circulation types reveals connections missed by analyses relying on monthly or seasonal values. Our results underscore the necessity to better diagnose process misrepresentation in climate models to progress with bias adjustment and impact modeling.

  • 47. Addor, Nans
    et al.
    Rössler, Ole
    Köplin, Nina
    Huss, Matthias
    Weingartner, Rolf
    Seibert, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Robust changes and sources of uncertainty in the projected hydrological regimes of Swiss catchments2014In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 50, no 10, 7541-7562 p.Article in journal (Refereed)
    Abstract [en]

    Projections of discharge are key for future water resources management. These projections are subject to uncertainties, which are difficult to handle in the decision process on adaptation strategies. Uncertainties arise from different sources such as the emission scenarios, the climate models and their postprocessing, the hydrological models, and the natural variability. Here we present a detailed and quantitative uncertainty assessment, based on recent climate scenarios for Switzerland (CH2011 data set) and covering catchments representative for midlatitude alpine areas. This study relies on a particularly wide range of discharge projections resulting from the factorial combination of 3 emission scenarios, 10–20 regional climate models, 2 postprocessing methods, and 3 hydrological models of different complexity. This enabled us to decompose the uncertainty in the ensemble of projections using analyses of variance (ANOVA). We applied the same modeling setup to six catchments to assess the influence of catchment characteristics on the projected streamflow, and focused on changes in the annual discharge cycle. The uncertainties captured by our setup originate mainly from the climate models and natural climate variability, but the choice of emission scenario plays a large role by the end of the 21st century. The contribution of the hydrological models to the projection uncertainty varied strongly with catchment elevation. The discharge changes were compared to the estimated natural decadal variability, which revealed that a climate change signal emerges even under the lowest emission scenario (RCP2.6) by the end of the century. Limiting emissions to RCP2.6 levels would nevertheless reduce the largest regime changes by the end of the century by approximately a factor of two, in comparison to impacts projected for the high emission scenario SRES A2. We finally show that robust regime changes emerge despite the projection uncertainty. These changes are significant and are consistent across a wide range of scenarios and catchments. We propose their identification as a way to aid decision making under uncertainty.

  • 48. Addor, Nans
    et al.
    Seibert, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Bias correction for hydrological impact studies: beyond the daily perspective2014In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 28, no 17, 4823-4828 p.Article in journal (Other academic)
  • 49. Adeyefa, ZD
    et al.
    Holmgren, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Spectral solar irradiance before and during a Harmattan dust spell1996In: Solar Energy, ISSN 0038-092X, Vol. 57, no 3, 195-203 p.195-203 p.Article in journal (Refereed)
    Abstract [en]

    Measurements of the ground-level spectral distributions of the direct, diffuse and global solar irradiance between 300 and 1100 nm were made at Akure (7.15°N, 5.5°E), Nigeria, in December 1991 before and during a Harmattan dust spell employing a spectroradiometer (LICOR LI-1800) with 6 nm resolution. The direct spectral solar irradiance which was initially reduced before the dust storm was further attenuated by about 50% after the spell. Estimated values of the Ångström turbidity coefficient β indicated an increase of about 146% of this parameter while the Ångström wavelength-exponent α decreased by about 65% within the 2-day study period. The spectral diffuse-to-direct and diffuse-to-global ratios suggest that the main cause of the significant reduction in solar irradiance at the surface was the scattering by the aerosol which led to an increase in the diffuse component. The global irradiance though reduced, was less sensitive to changing Harmattan conditions. It is recommended that solar energy devices that use radiation from Sun and sky be used under fluctuating Harmattan conditions. There are some deviations from the Ångström formula under very turbid Harmattan conditions which could be explained by the relative increase of the particle sizes.

  • 50. Adinugroho, Sigit
    et al.
    Vallot, Dorothée
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Westrin, Pontus
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Strand, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Calving events detection and quantification from time-lapse images in Tunabreen glacier2015In: Proc. 9th International Conference on Information & Communication Technology and Systems, Piscataway, NJ: IEEE , 2015, 61-65 p.Conference paper (Refereed)
1234567 1 - 50 of 7354
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