Change search
ReferencesLink to record
Permanent link

Direct link
Integration of prognostic aerosol-cloud interactions in a chemistry transport model coupled offline to a regional climate model
SMHI, Research Department, Air quality.ORCID iD: 0000-0002-5709-7507
SMHI, Research Department, Air quality.ORCID iD: 0000-0001-5695-1356
SMHI, Research Department, Air quality.ORCID iD: 0000-0001-7853-932X
Show others and affiliations
2015 (English)In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, no 6, 1885-1898 p.Article in journal (Refereed) PublishedText
Abstract [en]

To reduce uncertainties and hence to obtain a better estimate of aerosol (direct and indirect) radiative forcing, next generation climate models aim for a tighter coupling between chemistry transport models and regional climate models and a better representation of aerosol-cloud interactions. In this study, this coupling is done by first forcing the Rossby Center regional climate model (RCA4) with ERA-Interim lateral boundaries and sea surface temperature (SST) using the standard cloud droplet number concentration (CDNC) formulation (hereafter, referred to as the 'stand-alone RCA4 version' or 'CTRL' simulation). In the stand-alone RCA4 version, CDNCs are constants distinguishing only between land and ocean surface. The meteorology from this simulation is then used to drive the chemistry transport model, Multiple-scale Atmospheric Transport and Chemistry (MATCH), which is coupled online with the aerosol dynamics model, Sectional Aerosol module for Large Scale Applications (SALSA). CDNC fields obtained from MATCH-SALSA are then fed back into a new RCA4 simulation. In this new simulation (referred to as 'MOD' simulation), all parameters remain the same as in the first run except for the CDNCs provided by MATCH-SALSA. Simulations are carried out with this model setup for the period 2005-2012 over Europe, and the differences in cloud microphysical properties and radiative fluxes as a result of local CDNC changes and possible model responses are analysed. Our study shows substantial improvements in cloud microphysical properties with the input of the MATCH-SALSA derived 3-D CDNCs compared to the stand-alone RCA4 version. This model setup improves the spatial, seasonal and vertical distribution of CDNCs with a higher concentration observed over central Europe during boreal summer (JJA) and over eastern Europe and Russia during winter (DJF). Realistic cloud droplet radii (CD radii) values have been simulated with the maxima reaching 13 mu m, whereas in the stand-alone version the values reached only 5 mu m. A substantial improvement in the distribution of the cloud liquid-water paths (CLWP) was observed when compared to the satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) for the boreal summer months. The median and standard deviation values from the 'MOD' simulation are closer to observations than those obtained using the stand-alone RCA4 version. These changes resulted in a significant decrease in the total annual mean net fluxes at the top of the atmosphere (TOA) by -5 W m(-2) over the domain selected in the study. The TOA net fluxes from the 'MOD' simulation show a better agreement with the retrievals from the Clouds and the Earth's Radiant Energy System (CERES) instrument. The aerosol indirect effects are estimated in the 'MOD' simulation in comparison to the pre-industrial aerosol emissions (1900). Our simulations estimated the domain averaged annual mean total radiative forcing of -0.64 W m(-2) with a larger contribution from the first indirect aerosol effect (-0.57 W m(-2)) than from the second indirect aerosol effect (-0.14 W m(-2)).

Place, publisher, year, edition, pages
2015. Vol. 8, no 6, 1885-1898 p.
National Category
Climate Research
Research subject
URN: urn:nbn:se:smhi:diva-1972DOI: 10.5194/gmd-8-1885-2015ISI: 000357125000019OAI: diva2:923316
Available from: 2016-04-26 Created: 2016-03-03 Last updated: 2016-09-27Bibliographically approved

Open Access in DiVA

fulltext(4120 kB)4 downloads
File information
File name FULLTEXT01.pdfFile size 4120 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Thomas, Manu AnnaKahnert, MichaelAndersson, CamillaHansson, UlfJones, ColinLangner, JoakimDevasthale, Abhay
By organisation
Air qualityClimate research - Rossby CentreAtmospheric remote sensing
In the same journal
Geoscientific Model Development
Climate Research

Search outside of DiVA

GoogleGoogle Scholar
Total: 4 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 20 hits
ReferencesLink to record
Permanent link

Direct link