JMAGCM模拟的大气角动量函数Ⅰ.季节性分量(英文)

ATMOSPHERIC ANGULAR MOMENTUM FUNCTIONS SIMULATED BY JMA GCM I.SEASONAL COMPONENTS

大气角动量(AAM) 变化和地球自转变化密切相关,它们可应用于全球环流模型的检验.根据日本气象厅全球环流模型的输出数据计算出AAM 函数,将AAM 函数的模拟值与它的观测值以及地球自转变化序列相比较,来检验该模型对大气角动量的模拟.限于篇幅,仅给出AAM 函数的季节性分量模拟的结果.对于半年项,轴向AAM 函数的气压项和风项的模拟值都偏高,赤道向AAM 函数的气压项和风项很小,因而未予考虑;对于周年项,轴向AAM函数气压项的模拟值偏低,而赤道向AAM 函数气压项的模拟值偏高,轴向AAM 函数的风项模拟得最好,而赤道向AAM 函数的风项模拟得较差.总之,高精度的天文观测的地球自转系列可以作为全球环流模型检验的一种重要参考依据.

The atmospheric angular momentum (AAM) variation and the Earth's variable rotation are closely related to each other. They might be applied to the verification of global circulation models (GCMs). In the present paper, the authors calculate the AAM functions based on the output data of Japan Meteorological Agency (JMA) GCM, and then examine the model's simulation of AAM by comparing the model simulated values with the observed values of AAM functions as well as the Earth rotation variation series. Due to the limit of space, the authors present here only the results of AAM seasonal component simulations. For semi annual terms, the wind and pressure terms of axial AAM functions are all over estimated by the model. The wind and pressure terms of equatorial AAM functions are not considered due to their small amplitudes. For annual terms, the pressure terms of axial AAM functions are under estimated, while those of equatorial AAM functions are over estimated. The wind term of axial AAM functions is best simulated, while that of equatorial AAM functions is unsuccessfully estimated with the model. In general, the highly accurate astronomically observed Earth rotation series might serve as an important reference for the verification of global circulation models.