Abstract Author: Moon-Hyun Kim, Hyun-Suk Kang, Young-Hwa Byun, Suhee Park, Won-Tae Kwon and Dong-Hoon Kim
Abstract Title: Effects of the Dynamical Downscaling for Seasonal Forecast over East Asia: Wintertime Hindcast and its Analysis
Abstract: A dynamical downscaling system using the RegCM3 (Regional Climate Model Version 3) has been established to obtain regional details on seasonal forecast over East Asia. The operational seasonal forecast by the Korea Meteorological Administration (KMA) has been issued based on a global long-range forecast system, called GDAPS (Global Data Analysis and Prediction System) which has the T106 resolution. The RegCM3 consists of 96×80 grids with the 30 km resolution in the horizontal and 18 sigma-layers in the vertical. Initial and lateral boundary conditions as well as sea surface temperature are obtained from the GDAPS forecast. First, 10-year (1996~2005) wintertime climatology was produced by the RegCM3. Each year's hindcast consists of ten ensemble members with the 12-hour lagged initial conditions. In order to assess the downcaling effects, we compared GDAPS and RegCM3 forecasts with the observational reanalysis, i.e., NCEP/DOE reanalysis (R2) for atmospheric circulation as well as CMAP for precipitation. As results, seasonal mean fields' pattern of the lower-atmospheric temperature and precipitation are similar to each other between the model and reanalysis with a certain systematic (cold and wet) biases. However, the RegCM3 is well able to reflect the orography effects. In other to access regional details and added information by the dynamical downscaling, wintertime hindcasts are evaluated against the station measured observation and their results will be presented at the workshop.