大气对地球自转季节性变化的贡献

采用１９７９－１９９５年期间新的大气角动量资料，研究了大气在季节性时间尺度上对日长变化和极移的贡献。结果表明，考虑了风和大气压的贡献后，大气在周年和半年时间尺度上对日长变化的贡献分别可达９５％和８８％。同时还给出了大气对极移激发的定量结果，其中，大气的周年尺度上对极移Ｘ分同的贡献为１６％，对Ｙ分量的贡献为４３％；在半年尺度上海洋的贡献，才能进上步解决地球自转激发的问题。

CONTRIBUTION OF THE ATMOSPHERE TO THE SEASONAL EARTH ROTATION CHANGES

The contribution of AAM to earth rotation changes on seasonal time scale is studied in this paper. The new reanalysis of AAM data during 1979 - 1995 provided by NCEP/NCAR is used. The results show that the contributions of the atmosphere to the annual and semi-annual LOD changes are 95% and 88%, respectively, including the contributions of atmospheric wind and pressure. The results of the excitation to polar motion are also presented. On annual time scale, the contributions to X and Y components of polar motion are 16 96 and 43 %, respectively, while on semi-annual time scale, the contributions are 9% and 30%. It is pointed out that the oceans and wind above 10mbar should be considered in the research of earth rotation changes.