Atmospheric,hydrological and oceanic comprehensive contributions to seasonal polar wobble of Earth Rotation

The geophysical quantitative excitation on seasonal polar wobble of Earth Rotation has not been well achieved so far. The atmospheric, hydrologic and oceanic angular momentum variations are investigated from monthly values simulated by a coupled ocean-atmosphere general circulation model. The simulated equatorial AAM functions agree well with that from the JMA operational analysis in 90°:E direction, but disagree along Greenwich meridian. As for the annual cycle, not only the hydrologic and oceanic excitations partly match the residuals between geodetic functions of polar wobble and JMA AAM functions, but also the combinations with NCEP and JMA analysis AAM functions are better than those estimated from NCAR-CSM1 climate model.     

Chandler摆动周期和Q的理论值

本文基于简正模扰动理论,采用Zschau的地幔流变模型,在假设Chandler摆动的能量全部耗散于地幔滞弹性摩擦的条件下,首次导出Chandler摆动Q(Q_w)的理论值,所得结果与极大部分天文实测值非常一致。分析表明,地幔滞弹性很可能是Chandler摆动最主要的能量耗散源,Q_w的理论值为60—70。本文还给出Chandler摆动的其它理论参数,推算了吸收带模型参数α,研究了该模型的适用性,并讨论了Q_w与地幔Q(Q_m)的关系。     

大气、地表水和海洋对地球自转极移季节变化的综合贡献

极移季节变化的地球物理定量激发迄今未得到圆满的解释. 基于大气海洋耦合数值环流模式, 计算了大气和地表水及海洋角动量变化. 与日本气象局(JMA)客观分析资料计算的大气角动量比较, 模式模拟的大气角动量东经90°分量要优于0°分量. 地表水和海洋激发有效地减少了极移与JMA大气角动量之间季节尺度上的差异, 并且结合JMA和美国环境预测中心(NCEP)的大气角动量对极移周年变化的综合激发都优于NCAR-CSM1气候模式的结果.