本文利用WOA01(the Word Ocean Atlas 2001)海水各层气候态温盐数据计算南海Rossby波临界周期, 并与其在同纬度西北太平洋中的分布对比。结果显示, 在南海中Rossby波临界周期随纬度增加而逐渐增加, 并且由于南海的特殊地形, 海盆中Rossby波临界周期呈北东—南西向分布, 与其在大洋中呈纬向带状分布不同。通过分析南海各网格点上海面高度异常(SSHA, the sea surface height anomaly)的能谱, 我们发现在海盆中部其临界周期与当地Rossby波临界周期基本相同, 其值也随纬度增加而逐渐增加, 因而从观测上验证了模式结果, 即在海面风应力旋度能谱临界周期小于等于当地Rossby波临界周期的条件下, 海洋响应能谱临界周期等于当地Rossby波临界周期。

Using the climatological ocean temperature and salinity data from the Word Ocean Atlas 2001 (WOA01), the authors analyze the distribution of Rossby waves’ critical periods in the South China Sea (SCS) and compare the distribution in the SCS with that in the Northwest Pacific at the same latitude. The result shows that Rossby waves’ critical periods become longer at higher latitudes. Because of the special topography in the SCS, the isolines of Rossby waves’ critical periods in the SCS stretch in a northeast-southwest direction rather than zonally as in the North Pacific. From analyzing the power spectra of the sea-surface height anomalies (SSHA) in the SCS, we find that in the central SCS each of the SSHA power spectral critical periods is close to the local Rossby waves’ critical period and presents similar change of the Rossby critical period as latitude increases. From observations, they validate the theoretical prediction that when the critical period of the wind stress curl power spectrum is equal or smaller than that of the local Rossby waves’ the critical period of the ocean responding power spectrum equals to that of the local Rossby waves’.

中国科学院知识创新工程重大项目(KZCX1-YW-12-01); 中国科学院领域前沿项目(LYQY200702); 国家自然科学基金(40776008, 40976010)

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