A51T-06
Impact of 3-D Radiation-Topography Interaction on Indian Summer Monsoon and Hydrology in Himalayas
Friday, 18 December 2015: 09:00
3006 (Moscone West)
Wei-Liang Lee1, Kuo-Nan Liou2, Yu Gu2, Chi-Hua Wu3, L. Ruby Leung4 and Huang-Hsiung Hsu3, (1)Academia Sinica, Taipei, Taiwan, (2)University of California Los Angeles, Los Angeles, CA, United States, (3)Research Center for Environmental Changes Academia Sinica, Taipei, Taiwan, (4)Pacific Northwest National Laboratory, Richland, WA, United States
Abstract:
We have developed a parameterization to evaluate the 3-D topography effect on surface solar flux on the basis of a Monte Carlo approach simulating interactions between sunlight and rugged terrain. This parameterization has been implemented into NCAR CCSM4 to quantify the impacts of reflection and shading of shortwave radiation on climate simulation. The sensitivity experiment is carried out using CCSM4 with prescribed sea surface temperature of Year 2000. The results show that the 3-D radiation-topography interaction could enhance monsoon precipitation along the Himalayas due to the additional shortwave radiative heating at the southern slope of the Himalayas, which also causes strengthened and eastward-extended South Asian High. However, the precipitation is reduced over the Bay of Bengal, probably associated with the weakened Somali Jet. In winter, the additional radiative heating in the Himalayas increases the snowmelt rates, leading to decreases in snow depth and snow cover over the southern Tibetan Plateau.
