基于CCSM3气候模式的同化模拟试验

基于美国NCAR及其他科学家合作发展的共同气候系统模式CCSM3,利用nudging方法开展了把15 m到465 m的次表层海温同化到该模式的研究。1980—2000年的同化试验结果表明,经过同化得到的模拟结果与实际较为一致,较好的再现了中低纬太平洋海洋和大气的平均特征和随时间演变的规律,但仍存在如海表温度偏高、降水偏强等问题。尤其是在大洋的东边界,陆地地形比较陡峭的地区,通常出现较大的偏差。

Assimilation modeling by using CCSM3 model

The Community Climate System Model version 3 (CCSM3) is of a project which is within the Climate & Global Dynamics Division (CGD) of the Earth and Sun Systems Laboratory (ESSL) at the National Center for Atmospheric Research (NCAR). It has recently been developed and released to the climate community. CCSM3 is a coupled climate model with components representing the atmosphere, ocean, sea ice, and land surface connected by a flux coupler. According temperature restoring of ocean component model POP, GODAS analysis sub-surface temperature data was assimilated to POP model by nudging method. The results of simulation from 1980 to 2000 indicate that the numerical results related to ENSO matched with observation very well including sea surface temperature, sea surface currents, precipitation, zonal wind and sea level pressure. It could simulate ocean and atmosphere temporal and spatial variations well in low latitude regions of Pacific. However, there were positive biases on sea surface temperature, precipitation and so on. One kind of bias is from oceanic or atmospheric model alone and the other one from dynamic and thermodynamic flux couple.