COSMO-CLM 동아시아 기후 모의성능 평가-스펙트럴 넛징 효과 비교-

Abstract

This study evaluates climate simulations performed over the CORDEX Phase 2 East Asia domain with a Regional Climate Model (RCM), Consortium for Small-scale Modelling (COSMO)- Climate Limited-area Modelling (CLM) (CCLM), driven by the European Centre for Medium- Range Weather Forecast (ECMWF) Reanalysis (ERA)-Interim reanalysis. We focus on examining the influence of spectral nudging on East Asian climate simulations by comparing a control simulation to a simulation including spectral nudging. Spatio-temporal climatology of temperature and precipitation is well reproduced by CCLM with distinct regional patterns of systematic biases. Improvement of CCLM performance on East Asian climate simulation is identified when applying a spectral nudging technique. The use of spectral nudging alleviates systematic biases existing on horizontal winds and geopotential heights during summer and winter. Stronger reduction in systematic biases is found at lower troposphere during summer, partly explaining improvement of summer precipitation over the northeast Asia. Bias and RMSE analysis shows considerable improvement occurring in both climatology and inter-annual variability of summer precipitation and winter temperature over South Korea. Results from a Taylor diagram analysis reveal that CCLM reproduces the observed spatial patterns reasonably well for both summer and winter, and that spectral nudging improves spatial pattern simulations of horizontal winds and geopotential height at 850hPa during summer.