气候变暖下海面高度变化的数值模拟

Numerical Simulation of Sea Level Changes Under the Global Warming

应用压力坐标下的MITgcm模式,建立了一个非Boussinesq近似下的全球海洋环流模式,应用ERSST数据集提供的全球1855—2010年的海表面温度数据作为强迫条件,对近156a来全球海平面的变化情况进行了模拟和分析。并且根据对未来气候变化趋势的预测,对未来80a内全球海平面变化进行了模拟,得到了如下的结论:1)全球海平面高度存在上升的现象。2010年全球平均海平面相对于常年(即1975—1993年)上升43.8mm,中国近海平均海平面相对于常年上升54.8mm。2)2010年全球海平面变化情况,全球海平面上升幅度较大的区域主要为:西北太平洋、北太平洋中部、南太平洋中部和北大西洋。3)渤海、黄海、东海和南海四个海区海平面上升幅度各不相同,黄东海海平面上升幅度略高,南海海平面上升幅度最小。中国近海海平面上升速度慢于邻近的西北太平洋海区。4)若全球温度变化情况与预测相同,那么未来80a后,全球平均海平面上升速度远远超过现今水平。最后依据本文研究得到的结果,探讨了模拟长时间尺度过程海平面变化的数值模式所面临的问题。

The global sea level changes in almost 156 years are numerically simulated and analyzed by set- ting up a non-Boussinesq approximation global ocean circulation model through the application of the pres- sure coordinates of the MITgem mode, and by using the global sea surface temperature data provided by the ERSST data set and collected from 1855 to 2010 as the forced condition. And the global sea level chan- ges in the future 80 years are also simulated based on the prediction of the future climate change trend. The conclusions thus obtained are. 1） the global sea level height is rising. For instance, relatively to the perennial （i. e. , 1975--1993）, the mean sea level in 2010 raised 43.8 mm globally and 54.8 mm in the coastal waters of China; 2） in 2010 the regions where the global sea level raised in a larger range are mainly the Northwest Pacific, the North Atlantic and the central areas of the North Pacific and the South Pacific; 3） the ranges of the sea level rising are not identical in the four seas of China （i. e. the Bohai Sea, the Yellow Sea, the East China Sea and the South China Sea）, of which the ranges of the sea level rising are relatively larger in the Yellow Sea and the East China Sea and minimal in the South China Sea. The speed of the sea level rising is slower in the coastal waters of China than in the nearby area of the Northwest Pa cific; and 4） if the global temperature change is the same as the predictions, the speed of the global mean sea level rising in the next 80 years would be much faster than the current one. Based on these results, problems probably occurring in the numerical simulation models by which a lone-term sea level change will be simulated are discussed.