P89  Update of the Land Surface Parameters for TaiwanÕs   Meteorological Simulation

Lin, Chin-Fang, Fang-Yi Cheng, Chih-Hsiang Wu, Jeng-Lin Tsai, National Central University, Taiwan.

The accurate determination of the surface momentum, heat and moisture fluxes is strongly dependent on the accuracy of the land surface parameters. In this study, the mesoscale meteorological simulation using WRF is performed for the area in Taiwan by using the updated land use (LU) type, terrain height and roughness length (Z0). The updated LU data were reclassified using the 2007 MODIS satellite image. The new LU data correctly represents Taiwan as mixtures of cropland, urban, and forestlands as well as the other land types. The elevation data is provided from NASA Shuttle Radar Topographic Mission (SRTM) satellite image. The Z0 is recalculated using the arithmetic mean of the fraction of each LU type and the corresponded Z0. Several WRF sensitivities are performed using the updated land surface parameters. The simulation using the updated LU data shows higher temperature and lower wind speed than the run using the default setup due to the increasement of the urban and forest areas. The simulation using the SRTM data improves the temperature biases particularly in the mountain area. The newer roughness length data was about an order higher than the default setup and the simulation result shows the enhancement of the temperature diurnal variation and improves the wind speed.