大气角动量变化以及对地球自转季节变化的激发  

Atmospheric Angular Momentum Fluctuations and the Excitations on Earth Rotation at Seasonal Scale

作　　者：钟敏[1] 闫昊明[1] 朱耀仲[1] 雷小平[1] 

机构地区：[1]中国科学院测量与地球物理研究所动力大地测量学开放室,武汉430077

出　　处：《天文学报》2002年第1期90-98,共9页Acta Astronomica Sinica

基　　金：国家自然科学基金(批准号 49904002);国家攀登项目(970231003)资助

摘　　要：利用日本气象局 ＡＭＩＰⅡ大气数值模式的输出结果，基于ＢＰ方法和 ＳＰ方法计算了１９７９年至１９９６年大气角动量变化以及对地球自转季节变化激发的差异．利用最小二乘谐波拟合方法和气候平均图方法，分析了大气角动量的季节变化，并与同时期采用ＮＣＥＰ再分析资料和ＪＭＡ客观分析资料计算的大气角动量进行比较．The atmospheric contributions to seasonal variations in polar wobble and length of day are discussed for the period 1985-1995. The atmospheric motion is a main excitation source for Earth Rotation, which variation can duly reflect polar wobble and length of day change on all relevant time-scales, ranging from months to several years. The atmospheric angular momentum functions, calculated from the output data of GSM9603 GCM of Japan Meteorological Agency (JMA) anticipating in the second phase of atmospheric model inter-comparison project (AMIP II), are compared with those calculated from the reanalysis data of the National Centers for the Environmental Prediction (NCEP) / National Center for Atmospheric Research (NCAR), and from the operational objective analysis data of JMA, respectively. The results show that the different vertical wind integration methods lead to different wind contributions to the functions inferred from the observed wobble in seasonal variations, especially for the component along Greenwich meridian direction in annual variation. During the period from 1985 to 1995, the agreements of the pressure terms among these three equatorial AAM functions along 900 East are better than those are along Greenwich meridian direction. The axial relative AAM function simulated from GSM 9603 agrees well with the other two relative AAM functions in seasonal variations, with more moderate amplitudes better than the composite axial relative AAM functions estimated from 23 GCM models anticipating in the first phase of AMIP. In addition, its inter-annual variation from 1979 to 1996 shows the main characteristics of ENSO evolution as the axial relative AAM function estimated from NCEP reanalysis data, except for the period of anomalous ENSO from 1991 to 1993.

关 键 词：大气解动量 地球自转 大气环流模式比较计划 AMIP 季节变化 

分 类 号：P183.31[天文地球—天文学] P433