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| Titel |
Impact of boundary conditions on RegCM4 20-year-long precipitation simulations over CORDEX-East Asia domain |
| VerfasserIn |
J.-H. Park, S. G. Oh, M. S. Suh, H. S. Kang |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250061924
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| Zusammenfassung |
| National Institute of Meteorological Research (NIMR) of KMA organizes a domestic
collaborative research project for contributing CORDEX-East Asia. Within the evaluation
framework of CORDEX, the preliminary goal of the project is to produce 20-year-long
regional climate and to analyse the simulation results from four RCMs including RegCM4
driven by two boundary conditions. The final goal of this project is to predict the future
climate over this region using multiple RCMs based on the new scenario, RCPs. The number
of grid points for north-south and east-west directions is 197 x 233 and horizontal resolution
is 50 km. In this work, the simulation results of 20-year (1989-2008) regional climate over
CORDEX-East Asia by RegCM4 will be presented with focus on the precipitation and
impacts of lateral boundary conditions, the ERA-Interim (ERA) and NCEP/DOE (R2). For
the validation of RegCM4 simulations, global dataset (GPCP) and climate stations
data (precipitation) from KMA were used. The RegCM4 adequately captures the
seasonal evolution of precipitation associated to the seasonal march of East Asia
monsoon. The RegCM4 well simulates spatial and temporal (inter-annual, seasonal and
diurnal) variations of precipitation over CORDEX-East Asia. In general, RegCM4
overestimates precipitation over western South Pacific Sea and southern area of China. On
the other hand, summer precipitation over the Korean peninsula is significantly
underestimated, especially when driven by R2. In spatial distribution, the RegCM4
driven by ERA simulated more precipitation than that by R2 especially over land.
On the other hand, precipitation over the ocean is underestimated when driven
by ERA compared to that by R2. Although the performance skill of RegCM4 for
precipitation is clearly different with location and season, it well simulates seasonal
variation of precipitation over East Asia. However, it fails to capture the inter-annual
variation of precipitation. In addition, RegCM4 fails to capture the strong diurnal
variation of precipitation over South Korea. In general, the performance skills of
RegCM4 driven by ERA are higher correlation (smaller bias) than that using R2
over the entire domain regardless of the season. Similar results are found in the
frequency distribution of precipitation according to the intensity although RegCM4
overestimates weak precipitation below 25mm/day and underestimates heavy precipitation
above 25mm/day. The impacts of BCs on the simulated precipitation are underway. |
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