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| Titel |
Analysis of the Indian summer monsoon system in the regional climate model COSMO-CLM |
| VerfasserIn |
Bodo Ahrens, Andreas Dobler |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250036859
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| Zusammenfassung |
| The Indian summer monsoon (ISM) influences daily lives and economies in many countries
in the South Asian region. This study analyzes the representation of the ISM system in the
regional climate model COSMO-CLM. Simulations driven by ERA40 reanalysis
and present-day (1960-2000) data from the global climate mode l ECHAM5 are
investigated. The ability of the COSMO-CLM to reproduce the ISM better than the
coarser-grid driving models is tested using a set of well established, complementary
monsoon indices: the all-India monsoon rainfall, vertical wind shear indices and an
outgoing longwave radiation (OLR) index. The results show that regarding these
large-scale indices the COSMO-CLM simulations are not more accurate than the
driving models. Considering the spatial distribution of rainfall, the ERA40-driven
COSMO-CLM simulations show major overestimations (about 100%) for the west coast
of India, and underestimations (about 50%) for the Himalayan foothills. Large
biases occur in the OLR data over the Arabian Sea and the Bay of Bengal where the
COSMO-CLM shows high convective activity (OLR < 180 W m -2) at about three times as
many days as observed in the monsoon season. In the ECHAM5-driven simulation
underestimations of rainfall appear at the Himalayan foothills, too. Nevertheless, the
application of COSMO-CLM to ECHAM5 improves the temporal correlations
of the modeled ISM indices, and the spatial patterns are better simulated in the
COSMO-CLM with 0.44° horizontal grid-spacing than in the large-scale ECHAM5
data. |
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