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Hydro-climatic changes in irrigated world regions
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Understanding of hydro-climatic changes in the world’s river basins is required to ensure future food security. Different regional basins experience different levels of hydro-climatic change depending on the endorheic or exorheic nature of a hydrological basin, along with the climatic conditions and human land and water-use practices, for instance for irrigation. This thesis has analyzed long-term hydro-climatic changes in two main irrigated regions of the world: the Mahanadi River Basin in India and the Aral region in Central Asia. Thesis applies a basin-wise, data-driven water balance-constrained approach to quantifying the hydro-climatic changes, and to distinguish their main drivers in the past century and for future. Results point at human water-use and re-distribution for irrigation within a basin as a major driver of water balance changes, which also affect surface temperature in the region.

Cross-regional comparison focused on the climatically important changes of water, vapor and latent heat fluxes at the land surface, and also on the changes to water resource availability in the landscape. Results show that irrigation- driven changes in evapotranspiration, latent heat fluxes and associated temperature changes at land surface may be greater in regions with small relative irrigation impacts on water availability in the landscape than in regions with severe such impacts. This implies that one cannot from the knowledge about only one aspect of hydro-climatic change simply extrapolate the impact importance of those changes for other types of water changes in a region.

Climate model projections results show lack of consistency in individual GCM performance with regard to temperature and to precipitation, implying difficulties to identify well-performing GCMs with regard to both of these variables in a region. In Aral region, the thesis shows that ensemble mean of different GCM outputs may provide robust projection of future hydro-climate changes.

Place, publisher, year, edition, pages
Stockholm: Department of Physical Geography and Quaternary Geology, Stockholm University , 2013. , 30 p.
Series
Dissertations from the Department of Physical Geography and Quaternary Geology, ISSN 1653-7211 ; 36
Keyword [en]
Climate change, hydro-climatic change, evapotranspiration, irrigation, water demand, water balance, land-use, water-use, hydrological catchment, Aral Sea, India, Mahanadi River Basin
National Category
Climate Research Physical Geography
Research subject
Physical Geography
Identifiers
URN: urn:nbn:se:su:diva-87921ISBN: 978-91-7447-641-5 (print)OAI: oai:DiVA.org:su-87921DiVA: diva2:607687
Public defence
2013-04-03, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 12, Stockholm, 13:00 (English)
Opponent
Supervisors
Funder
FormasLinnaeus research environment CADICSModelling initiative of the Bert Bolin Centre for Climate ChangeSida - Swedish International Development Cooperation AgencySwedish Research Council, 2006-4366
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Accepted. Paper 6: Manuscript.

Available from: 2013-03-12 Created: 2013-02-25 Last updated: 2013-02-27Bibliographically approved
List of papers
1. Analysis of water resources in the Mahanadi River Basin, India under projected climate conditions
Open this publication in new window or tab >>Analysis of water resources in the Mahanadi River Basin, India under projected climate conditions
2008 (English)In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 22, no 18, 3589-3603 p.Article in journal (Refereed) Published
Abstract [en]

The paper presents the outcomes of a study conducted to analyse water resources availability and demand in the Mahanadi River Basin in India under climate change conditions. Climate change impact analysis was carried out for the years 2000, 2025, 2050, 2075 and 2100, for the months of September and April (representing wet and dry months), at a sub-catchment level. A physically based distributed hydrologic model (DHM) was used for estimation of the present water availability. For future scenarios under climate change conditions, precipitation output of Canadian Centre for Climate Modelling and Analysis General Circulation Model (CGCM2) was used as the input data for the DHM. The model results show that the highest increase in peak runoff (38%) in the Mahanadi River outlet will occur during September, for the period 2075-2100 and the maximum decrease in average runoff (32·5%) will be in April, for the period 2050-2075. The outcomes indicate that the Mahanadi River Basin is expected to experience progressively increasing intensities of flood in September and drought in April over the considered years. The sectors of domestic, irrigation and industry were considered for water demand estimation. The outcomes of the analysis on present water use indicated a high water abstraction by the irrigation sector. Future water demand shows an increasing trend until 2050, beyond which the demand will decrease owing to the assumed regulation of population explosion. From the simulated future water availability and projected water demand, water stress was computed. Among the six sub-catchments, the sub-catchment six shows the peak water demand. This study hence emphasizes on the need for re-defining water management policies, by incorporating hydrological response of the basin to the long-term climate change, which will help in developing appropriate flood and drought mitigation measures at the basin level.

Keyword
climate change, distributed hydrologic model, general circulation model, water availability and demand, Mahanadi river basin
National Category
Climate Research Physical Geography
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-17055 (URN)10.1002/hyp.6962 (DOI)
Available from: 2009-01-05 Created: 2009-01-05 Last updated: 2017-12-13Bibliographically approved
2. Vapor flux by evapotranspiration: effects of changes in climate, land-use and water-use
Open this publication in new window or tab >>Vapor flux by evapotranspiration: effects of changes in climate, land-use and water-use
2010 (English)In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 115, no D24Article in journal (Refereed) Published
Abstract [en]

Enhanced evapotranspiration (ET) over irrigated land and associated latent heat flux change can modify the climate. Model studies of such climate change effects of irrigation are commonly based on land use parameterizations, in terms of irrigated land area, or land area equipped for irrigation. Actual ET change, however, may also be driven by water use change in addition to land use change. This study quantifies and compares ET changes due to changes in climate, land use, and water use from the preirrigation period 1901–1955 to the recent period 1990–2000 (with irrigation) for the example case of Mahanadi River Basin (MRB) in India. The results show that actual water use per unit area of irrigated land may vary greatly over a hydrological drainage basin. In MRB, much higher water use per irrigated land unit in the downstream humid basin parts leads to higher vapor flux by ET, and irrigation‐induced ET flux change, than in the upstream, water‐stressed basin parts. This is consistent with water supply limitations in water‐stressed basins. In contrast, the assumption in land use−based models that irrigation maintains high soil moisture contents can imply higher modeled water use and therefore also higher modeled ET fluxes under dry conditions than under humid conditions. The present results indicate water use as an important driver of regional climate change, in addition to land use and greenhouse gas‐driven changes.

Keyword
evapotranspiration, water use, land use, climate change
National Category
Climate Research Physical Geography
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-51192 (URN)10.1029/2010JD014417 (DOI)
Available from: 2011-01-10 Created: 2011-01-10 Last updated: 2017-12-11Bibliographically approved
3. Inland hydro-climatic interaction: Effects of human water use on regional climate
Open this publication in new window or tab >>Inland hydro-climatic interaction: Effects of human water use on regional climate
2010 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 37, no 18, L18402- p.Article in journal (Refereed) Published
Abstract [en]

This study has quantified the regional evaporation and evapotranspiration changes, and the associated latent heat flux and surface temperature changes in the Central Asian region of the Aral Sea drainage basin and the Aral Sea itself from the pre-1950 period of the 20th century to 1983-2002. The human water use for irrigation yielded an average regional cooling effect of -0.6 degrees C due to increased evapotranspiration and latent heat flux from the irrigated land. The runoff water diverted for irrigation was more than 80% of the pre-1950 runoff into the terminal Aral Sea, and was largely lost from the regional water system by the evapotranspiration increase. The Aral Sea shrank due to this water loss, resulting in decreased evaporation and latent heat flux from the pre-1950 Aral Sea area extent, with an average regional warming effect of 0.5 degrees C. In general, the endorheic (land-internal) runoff and relative consumptive use of irrigation water from that runoff determine the relative inland water area shrinkage, its warming effect, and to what extent the warming counteracts the cooling effect of irrigation. Citation: Destouni, G., S. M. Asokan, and J. Jarsjo (2010), Inland hydro-climatic interaction: Effects of human water use on regional climate.

Keyword
regional climate, hydrological catchment, climate change, evapotranspiration, latent heat flux
National Category
Climate Research Physical Geography
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-49433 (URN)10.1029/2010GL044153 (DOI)000282318200005 ()
Note

authorCount :3

Available from: 2010-12-17 Created: 2010-12-14 Last updated: 2017-12-11Bibliographically approved
4. Irrigation effects on hydro-climatic change: Basin-wise water balance-constrained quantification and cross-regional comparison
Open this publication in new window or tab >>Irrigation effects on hydro-climatic change: Basin-wise water balance-constrained quantification and cross-regional comparison
2014 (English)In: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 35, no 3, 879-895 p.Article in journal (Refereed) Published
Abstract [en]

Hydro-climatic changes driven by human land and water use, including water use for irrigation, may be difficult to distinguish fromthe effects of global, natural and anthropogenic climate change. This paper quantifies and compares the hydro-climatic change effects ofirrigation using a data-driven, basin-wise quantification approach in two different irrigated world regions: the Aral Sea drainage basinin Central Asia, and the Indian Mahanadi River Basin draining into the Bay of Bengal. Results show that irrigation-driven changesin evapotranspiration and latent heat fluxes and associated temperature changes at the land surface may be greater in regions withsmall relative irrigation impacts on water availability in the landscape (here represented by the MRB) than in regions with severe suchimpacts (here represented by the Aral region). Different perspectives on the continental part of Earth’s hydrological cycle may thus implydifferent importance assessment of various drivers and impacts of hydro-climatic change. Regardless of perspective, however, actualbasin-wise water balance constraints should be accounted to realistically understand and accurately quantify continental water change.

Keyword
hydro-climatic change, irrigation, evapotranspiration, surface temperature, hydrological cycle, hydrological catchment, Aral Sea, India
National Category
Climate Research Physical Geography
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-87957 (URN)10.1007/s10712-013-9223-5 (DOI)000333700700018 ()
Available from: 2013-02-27 Created: 2013-02-27 Last updated: 2017-12-06Bibliographically approved
5. Hydrological responses to climate change conditioned by historic alterations of land use and water use
Open this publication in new window or tab >>Hydrological responses to climate change conditioned by historic alterations of land use and water use
Show others...
2012 (English)In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 16, no 5, 1335-1347 p.Article in journal (Refereed) Published
Abstract [en]

This paper quantifies and conditions expected hydrological responses in the Aral Sea Drainage Basin (ASDB; occupying 1.3% of the earth's land surface), Central Asia, to multi-model projections of climate change in the region from 20 general circulation models (GCMs). The aim is to investigate how uncertainties of future climate change interact with the effects of historic human re-distributions of water for land irrigation to influence future water fluxes and water resources. So far, historic irrigation changes have greatly amplified water losses by evapotranspiration (ET) in the ASDB, whereas 20th century climate change has not much affected the regional net water loss to the atmosphere. Results show that errors in temperature (T) and precipitation (P) from single GCMs have large influence on projected change trends (for the period 2010-2039) of river runoff (R), even though the ASDB is spatially well resolved by current GCMs. By contrast, observed biases in GCM ensemble mean results have relatively small influence on projected R change trends. Ensemble mean results show that projected future climate change will considerably increase the net water loss to the atmosphere. Furthermore, the ET response strength to any future T change will be further increased by maintained (or increased) irrigation practices, which shows how climate change and water use change can interact in modifying ET (and R). With maintained irrigation practices, R is likely to decrease to near-total depletion, with risk for cascading ecological regime shifts in aquatic ecosystems downstream of irrigated land areas. Without irrigation, the agricultural areas of the principal Syr Darya river basin could sustain a 50% higher T increase (of 2.3 A degrees C instead of the projected 1.5 A degrees C until 2010-2039) before yielding the same consumptive ET increase and associated R decrease as with the present irrigation practices.

National Category
Climate Research Physical Geography
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-79719 (URN)10.5194/hess-16-1335-2012 (DOI)000304049700006 ()
Note

AuthorCount:5;

Available from: 2012-09-12 Created: 2012-09-11 Last updated: 2017-12-07Bibliographically approved
6. Appendix to Paper V: Climate model performance versus basin-scalehydro-climatic data
Open this publication in new window or tab >>Appendix to Paper V: Climate model performance versus basin-scalehydro-climatic data
(English)Manuscript (preprint) (Other academic)
National Category
Climate Research Physical Geography
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-87958 (URN)
Available from: 2013-02-27 Created: 2013-02-27 Last updated: 2013-02-27Bibliographically approved

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