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| Titel |
SST and circulation trend biases cause an underestimation of European precipitation trends |
| VerfasserIn |
G. J. van Oldenborgh, G. Lenderink, M. Collins |
| 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 |
250028991
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| Zusammenfassung |
| Over the last 100 years there are have been clear precipitation trends in Europe. In winter,
precipitation has increased in north-western Europe. In summer, there has been an increase
along many coasts in the same area.
An investigation of precipitation trends in three multi-model ensembles including both
global and regional climate models shows that these models have trouble reproducing the
observed trends. In many regions the observation fall outside the bandwidth of natural
variability combined with model uncertainty as parametrised by the multi-model ensemble.
Conversely, the ensemble mean falls outside the error margins of the observed trends in the
same regions.
In contrast, regional climate model experiments with observed boundary conditions show
precipitation trends that are in good agreement with observations. We investigate the
relative importance of the two prescribed factors: atmospheric circulation and sea
surface temperature in setting the observed trend. The causes of the large trends in
atmospheric circulation are not known, the lower SST trend in climate models is due to
well-known problems in low-resolution ocean models. Improving the ocean models used
for climate projections will therefore lead to more realistic precipitation trends. |
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