PRESENT-DAY ANTARCTIC CLIMATOLOGY OF THE NCAR COMMUNITY CLIMATE MODELVERSION-1

Five-year seasonal cycle output produced by the NCAR Community Climate Model Version 1 (CCM1) with R15 resolution is used to evaluate the ab ility of the model to simulate the present-day climate of Antarctica. The model results are compared with observed horizontal syntheses and point data. Katabatic winds, surface temperatures over the continent, the circumpolar trough, the vertical motion field, the split jet strea m over the Pacific Ocean, and the snowfall accumulation are analyzed. The results show that the CCM1 with R15 resolution can well simulate t o some extent the dynamics of Antarctic climate not only for the synop tic scale, but also for some mesoscale features (mesoscale cyclogenesi s). This is reflected in the zonal-mean pattern of vertical motion by the presence of two convergence centers. The finding suggests that the CCM1 might also capture the split jet stream over New Zealand in wint er, but the evidence is mixed. This is inferred to be due to inadequat e simulation of the thermal forcing over high southern latitudes. The CCM1 can also capture the phase and amplitude of the annual and semian nual variation of temperature, sea level pressure, and zonally average d zonal (E-W) wind. That the CCM1 can simulate some characteristics of the semiannual variation may be due to the improved radiation treatme nt compared to the earlier CCM0. The most dramatic shortcomings were a ssociated with the model's anomalously large precipitation amounts at high latitudes, which result from the scheme to suppress negative mois ture values. The simulations of cloudiness and the atmospheric heat ba lance are adversely affected. A greatly refined moisture budget scheme is needed to eliminate these problems and may allow the split jet-str eam feature over the New Zealand area in winter to be accurately repro duced. A coupled mesoscale-CCM1 model may be needed to adequately simu late the feedback from mesoscale cyclones to synoptic-scale weather sy stems, and the katabatic wind circulation.