2002 Annual

Tuesday, 15 January 2002: 4:30 PM
Characteristics of Cloud Radiative Forcing Over East Asia
Wei-Chyung Wang, SUNY, Albany, NY; and W. -. S. Kau, H. -. H. Hsu, and C. -. H. Tu
It is believed that the large differential surface heating between oceans and land surface during summer drives the East Asian summer monsoon (EASM) with distinctive characteristics of large cloud amounts, and heavy and persistent rainfall. Although the direct effects of clouds on the shortwave and longwave radiation are relatively understood, but the role of clouds played in the evolution of the EASM has not been studied, in particular in the vertical distribution of heating/cooling attributed to cloud, and its comparison with heating caused by convection and large-scale condensation. In this study, we use the cloud radiative forcing as a diagnostic index to study the role of cloud-radiation interaction in the EASM. Three aspects are investigated. First, the observed parameters of cloud cover, solar and thermal radiation, circulation and precipitation are used to study the spatial and temporal patterns of the individual parameters and their mutual consistency as well as their comparison with AMIP-CMIP model simulations. Next, we compare the inter-annual shortwave and longwave radiative forcing calculated from the AMIP-CMIP models. Finally, the NTU- and SUNYA-AMIP model simulations are used to examine the vertical heating/cooling distribution associated with clouds, and its comparison with other heating/cooling terms; comparisons with observation are also conducted to the extent possible.

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