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| Titel |
Drier Mediterranean Soils due to Greenhouse Warming bring easterly Winds over Summertime Central Europe |
| VerfasserIn |
R. J. Haarsma, F. M. Selten, B. vd Hurk, W. Hazeleger, X. Wang |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021525
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| Zusammenfassung |
| A robust result of greenhouse warming runs with global climate models is the
depletion of soil moisture in southern and central Europe in summer. This leads
to a strong increase in surface temperatures as a result of the accompanying
reduction of the surface cooling by evaporation. Analyses of simulations with
the ECHAM5/OMI and EC-EARTH global climate models demonstrate that this causes a
large-scale heat low response in the lower atmosphere. At its northern flank this
brings easterly winds over Central Europe. A statistical analyses of a large
ensemble made by the ECHAM5/OMI model indicates that the same mechanism operates
on intra-seasonal time scales: a weak relationship is found between dry
Mediterranean soils in June and low surface pressure in July-August. The dry
soils are related to reduced rainfall in January-May. This applies for
intra-seasonal time scales as well as for climate change due to greenhouse
warming. Additional idealized simulations confirm the relationship between large
surface warming and the development of a heat low. This induces a positive
feedback: dryer Mediterranean soils in summer bring easterly winds over Europe
increasing the continental character of Western Europe summer climate. |
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