84th AMS Annual Meeting

Tuesday, 13 January 2004: 9:00 AM
Development of new physics parameterization schemes and their impacts on MM5 and WRF prediction of heavy rainfall over Korea during 2001-2002
Room 6A
Tae-Young Lee, Yonsei Univ., Seoul, Korea; and S. -. Y. Hong, Y. Noh, and H. -. Y. Chun
New or improved parameterization schemes have been developed by LAMOR scientists for microphysics, cumulus convection, PBL, gravity wave drag, and land surface processes. A significantly revised ice microphysicscis after the Lin et al. and Rutledge and Hobbs was proposed and implemented onto the WRF model, as the WRF-Single-Moment-MicroPhysics (WSMMP). Major revisions include the incorporation of cloud-ice dependent ice number concentrations and related ice-microphysics changes, and the inclusion of ice sedimentation effect. Considering the nature of heavy rain over the Korean peninsula, a modified version of Grell scheme has been tested for cumulus convection. For PBL processes, a widely used nonlocal K-profile model (MRFPBL) has been improved in manymany respects. A major modification after the Troen and Mahrt is the inclusion of explicit treatment of entrainment processes at the top of the mixed layer. The scheme is implemented onto the WRF successfully, as the YonSei University PBL (YSU PBL). The SiB2 has been modified based on intensive surface observations for land surface processes, and compared with the results from the NOAH LSM. These new schemes for model physics have been evaluated individually through ideal experiments and compared well with with observations. The new parameterization schemes have been implemented in WRF to investigate their impacts on WRF prediction of heavy rainfall over the Korean peninsula. Prediction experiments have been carried out for 9 heavy rain events during 2001 and 2002. A set of experiment has been performed for each event: experiments with the new scheme and other existing schemes in WRF for individual model physics. Results have shown some significant impacts of new schemes in the prediction of some heavy rainfalls.

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