85th AMS Annual Meeting

Monday, 10 January 2005
Changes of the Asian-Australian monsoon by global warming simulated by the 20-km mesh MRI/JMA AGCM
Akio Kitoh, MRI, Tsukuba, Ibaraki, Japan
In this paper we present future changes of the Asian summer monsoon conducted by a time-slice experiment with a super-high resolution AGCM (20-km mesh TL959L60 MRI/JMA AGCM) performed by the RR2002 project "Development of Super High Resolution Global and Regional Climate Models" funded by MEXT. The SST in the AGCM is derived from the control run and the SRES A1B scenario run with the MRI-CGCM2.3 (T42L30 atmosphere, 0.5-2.0 x 2.5 L23 ocean) corresponding to the end of the 21st century.

Due to increased resolution, the land-sea distribution over the maritime continent is now well represented. Being different from low-resolution model results, a clear difference in precipitation change is found between land and ocean in the maritime continent area. An overall downward motion dominates in the maritime continent area associated with El-Nino like SST anomalies given by the coupled model. Oceanic area in the maritime continent region except for 5S-10N shows a decrease in precipitation by global warming, which is consistent with large-scale circulation anomalies, while nearby land area shows an increase in precipitation. There is also a change in diurnal cycle of precipitation over the two regions: over the ocean nighttime precipitation decreases and daytime precipitation increases, while over land nighttime precipitation increases and daytime precipitation decreases. These different characteristics in precipitation change between the ocean and land appraises a use of super-high resolution model for regional assessment of climate change.

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