理想化南极融冰方案的海洋边界条件初探

A preliminary study on the oceanic boundary condition of an idealized Antarctic ice sheet melting scheme

基于气候态的SODA(Simple Ocean Data Assimilation)数据,比较了气候态意义下南极附近和南极绕极流区域的海洋层结,对南极融冰问题的合理海洋边界条件进行了初步探讨。结果表明:南极融冰所注入的淡水通量在大西洋东部和印度洋海区将沿着表层路径到达南极绕极流区,在大西洋西部和太平洋的经向运动路径视淡水通量的强度而定:在融冰较为剧烈时,将沿表层路径到达绕极流区域;在融冰较为和缓时,将沿次表层路径向北运动。在此基础上,定量评估了淡水通量沿表层路径运动的临界情况,对目前大多数气候模式采用理想化淡水通量模拟南极融冰问题的合理性进行了分析,以期为南极融冰问题的模式方案选择提供必要的参考。

Using the Simple Ocean Data Assimilation（SODA） climatological data,we compared the climatological oceanic stratification around the Antarctic and the Antarctic Circumpolar Current（ACC） region to conduct a pre-liminary study on the reasonable oceanic boundary condition of Antarctic ice sheet melting.Our results indicate freshwater flux induced by ice-melting will advect along the surface path in the East Atlantic and Indian Ocean,while in the West Atlantic and Pacific Ocean,the meridional motion path of freshwater flux depends on the intensity of freshwater flux itself.When there appears intense ice-melting of Antarctic,freshwater will travel along the sur-face path;when ice-melting is relatively generous,subsurface path will be preferred by freshwater flux.On the ba-sis of these analyses,we quantitatively assessed the threshold state guaranteeing freshwater flux moving along sur-face path,and further analyzed the rationality of simulation of Antarctic ice-melting with idealized freshwater flux in most of current climate models,in order to providing neccessary reference for the selection of modeling strategy simulating the Antarctic ice-melting scenario.