BCC_CSM对全球海冰面积和厚度模拟及其误差成因分析

An Analysis of Simulated Global Sea Ice Extent, Thickness, and Causes of Error with the BCC_CSM Model

本文评估了国家气候中心发展的BCC_CSM模式对全球海冰的模拟能力,结果表明:该气候系统模式能够较好地模拟出全球海冰面积和厚度的时空分布特征,且南半球海冰模拟能力优于北半球。通过对比分析发现:年平均海冰面积模拟误差最大的区域位于鄂霍次克海、白令海和巴伦支海等海区,年平均海冰厚度分布与观测相近,在北半球冬季模拟的厚度偏薄;从海冰季节变化来看,模拟的夏季海冰面积偏低,冬季偏高;从海冰年际变化来看,近60年南北半球海冰面积模拟都比观测偏多,但南半球偏多幅度较小,然而北半球海冰年际变化趋势的模拟却好于南半球。另外,通过对海冰模拟误差成因分析,发现模拟的净辐射能量收入偏低使得海温异常偏冷,是导致北半球冬季海冰模拟偏多的主要原因。

In this study,we evaluate the global sea ice modeling capability of the Beijing Climate Center Climate System Model （BCC_CSM）.Comparative analysis results indicate that the model simulates the spatial and temporal distribution characteristics of global sea ice extent and thickness well and that its simulation performance in the Southern Hemisphere is better than that in the Northern Hemisphere.The maximum simulation bias of the annual mean sea ice extent （SIE）occurs in the Sea of Okhotsk,the Bering Sea,and the Barents Sea.The spatial distribution results for simulated sea ice thickness are similar to those from observation data,with thinner sea ice in the Northern Hemisphere winter.The mean annual cycle of sea ice extent has a negative bias in summer and a positive bias in winter,as compared with observation data.The annual mean SIE in the past 60 years in both the Northern and Southern Hemispheres is excessive,while the positive bias in the Southern Hemisphere is smaller.However,the simulated interannual variation trend in the Northem Hemisphere is more accurate.In addition,lower net radiation results lead to anomalous cold sea surface temperatures,which may be the main reason for the sea ice simulation error.