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Titel |
Regional Climate Simulations of Summer Diurnal Rainfall Variations over East Asia and Southeast China |
VerfasserIn |
W.-R. Huang, J. C. L. Chan |
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 |
250059636
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Zusammenfassung |
This study evaluates the simulations of summer (June-August) precipitation over East Asia by
the Regional Climate Model Version 3 (RegCM3), with emphasis on the diurnal variations of
precipitation over Southeast China (PSEC) during the 1998-2002 summer seasons. The
evaluation focuses on the maintenance mechanisms of the diurnal variations in PSEC as
proposed by previous observational studies. It is found that the diurnal variations of PSEC are
sensitive to the choice of cumulus parameterization schemes (CPSs). In particular, the Grell
scheme with the Frisch-Chappell convective closure assumption (GFC) produces reasonable
diurnal variations of PSEC. Other CPSs such as the Emanuel scheme produces a weaker
late-afternoon maximum of PSEC, and the Kuo scheme as well as the Grell scheme with the
Arakawa–Schubert closure assumption (GAS) is unable to simulate the occurrence of
the late-afternoon maximum of PSEC. The simulations show that the adoption of
the GFC scheme reproduces the large-scale land-sea breeze circulation and the
moisture flux convergence that have been documented by previous studies as the
maintenance mechanisms of the diurnal variations of PSEC. This feature illustrates the
importance of convective cloud feedback at the diurnal timescale in maintaining
the large-scale circulation. Furthermore, when the simulation domain covers the
entire Tibetan Plateau, the diurnal variations of precipitation over East Asia are
found to exhibit a noticeable improvement without changes in the physics schemes. |
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