FOAM模拟的20世纪气候变化

20^(th) Century Climate Change in FOAM

在加入温室气体和太阳常数后,FOAM较好地模拟出20世纪气候变化的主要特征,与IPCC AR4模式和观测的结果基本保持一致,主要特征如下:(1)全球平均地表气温升高约0.6~0.7℃,海表面温度升高约0.4~0.5℃;地表温度升高不均匀,冰面大于陆地,陆地大于海洋,北半球大于南半球;对流层变暖,平流层变冷。(2)中纬度西风增强,西风带和信风带都有往极地移动的趋势,在南半球更明显;南北半球增暖的不对称可能影响信风的变化。(3)海表面温度经向梯度增大,和中纬度西风增强有互为因果的关系。(4)中低纬度蒸发加强,大气中的水汽增加,水汽的温室效应增强。(5)海洋上层增暖,副热带地区更明显;高纬度海洋变淡,太平洋变淡,印度洋和大西洋中低纬度变咸;北大西洋热盐环流减弱。

With the annual forcing of greenhouse gases and solar constant, FOAM captures the main characteristics of 20th century climate change, in consistent with results of IPCC AR4 models and observation. These main characteristics in FOAM are as followings. （1） Global surface air temperature rises by 0. 6 ℃-0. 7 ℃, and global sea surface temperature by 0. 4 ℃ -0. 5 ℃. For temperature rise over different earth coverage, ice is larger than land, land larger than ocean, and the northern hemisphere larger than the southern hemisphere. The troposphere warms, while the stratosphere cools. （2） The mid-latitud~ westerly enhances, with the poleward migration of westerly belts and trade wind belts, which are more obvious in the southern hemisphere. The hemisphere warming asymmetry might effects the trade wind response to global warming. （3） The larger meridional sea surface temperature gradient might be the cause or result of the enhanced mid-latitude westerly. （4） There is more evaporation in the low and mid-latitude and more water vapor in atmosphere with enhanced greenhouse effect. （5） The up- per 700m ocean is warming, and the warming penetrates much deeper in the subtropical ocean. The high latitude ocean is fresher. Pacific Ocean becomes fresher, while Indian Ocean and low and mid-lati- tude Atlantic Ocean become saltier. The Atlantic Meridional Overturning Circulation decreases.