不同大西洋经圈翻转环流平均强度下中国气候的年代际响应特征

基于美国大气研究中心的CCSM3(Community Climate System Model version 3)模式,对淡水扰动试验中不同大西洋经圈翻转环流(Atlantic Meridional Overturning Circulation,AMOC)平均强度下,中国气候的年代际响应特征进行研究。结果表明:在年代际尺度上,中国区域地表气温和降水强度变化与AMOC强度变化的关系紧密,然而,不同平均强度下,中国气候的年代际响应特征不同。高平均强度下,中国区域地表气温升高,中国北部降水增多、南部降水减少;低平均强度下,则反之。不同平均强度下,中国区域年平均地表气温和降水EOF第一特征向量的空间分布存在显著差异:高平均强度下,地表气温呈现中国全区域一致的分布型,降水呈现自北向南的"-+-"型的雨带分布;低平均强度下,地表气温呈现中国区域南北反相的偶极子分布型,降水呈现自北向南的"-+"型的雨带分布。与低平均强度相比,在高平均强度下,EOF第一模态的时间系数的年代际变化尺度均更长。

Interdecadal response characteristics of climate in China under different mean intensities of Atlantic meridional overturning circulation

Based on the CCSM3 (Community Climate System Model version 3) model of the US National Center for Atmospheric Research,this paper studies the interdecadal response characteristics of climate in China under different mean intensities of Atlantic Meridional Overturning Circulation (AMOC) in the freshwater disturbance tests.Results show that the changes of surface temperature and precipitation intensity in China are closely related to the changes of AMOC intensity on interdecadal scale,but the response characteristics of China climate on interdecadal scale are different under different mean intensities.Under the high mean intensity,the surface temperature in China increases,the precipitation in northern China increases,and the precipitation in southern China decreases,whereas under the low mean intensity,the opposite is true.Under different mean intensities,the spatial distributions of the first EOF eigenvectors of annual mean surface temperature and precipitation in China are significantly different:Under the high mean intensity,the surface temperature presents a uniform distribution pattern in the whole region of China,and the precipitation presents a "-+-" type rain belt distribution from north to south;under the low mean intensity,the surface temperature shows a dipole distribution pattern of north-south inversion in China,and the precipitation shows a "-+" type rain belt distribution from north to south.Compared with the low mean intensity,the interdecadal variation scales of the time coefficients of the first EOF modes are longer under the high mean intensity.