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利用1992年12月—2007年5月的高度计资料,研究东海海平面的变化特征。分析表明,近14年来长江口海域及30°N以南东海海平面的平均上升高度分别为57.7 mm和40.9 mm,各海域的海平面上升速度不完全相同。研究发现,东海海平面与南方涛动指数(SO I)二者的低频分量具有明显的相关关系,东海海平面显著受SO I调制,但30°N两侧海域SLA与SO I的相关性相反。东海纬向风应力与当地SLA、SO I具有很好的相关性;大气环流的辐散带两侧风场的差异,导致两侧海域平均SLA与纬向风应力距平的低频分量之间的相关关系不同(30°N以南的海域二者呈负相关性,长江口海域则呈正相关性)。将坐标系进行旋转后,获得与当地海平面异常相关最大的风应力方向。对SLA与新坐标系下风应力距平u的低频分量分析发现,长江口海域、30°N以南东海对海平面影响最大的风应力距平u方向分别为东偏南70°、东偏南23°。风应力距平u分量与SLA、SO I的低频分量呈现更好的相关性,由于辐散带在大气环流中的调制作用,导致30°N两侧海域海平面和风应力距平u对SO I响应相反。ENSO通过大气环流过程对东海海域的风场产生影响,当地风场通过纬向风应力对东海海平面的年际变化产生调制作用。因此,ENSO可以通过风应力对东海海平面产生影响。
Using the altimeter data from December 1992 to May 2007, the variation characteristics of sea level in the East China Sea were studied. The analysis shows that in the recent 14 years, the average rising height of the sea level in the Changjiang Estuary and the south of 30 ° N is 57.7 mm and 40.9 mm, respectively. The sea level rise rates in all the sea areas are not exactly the same. It is found that there is a clear correlation between the sea level of the East China Sea and the low-frequency component of the Southern Oscillation Index (SOI). The sea level of the East China Sea is significantly modulated by SOI, but the correlation between SLA and SOI is opposite . The zonal wind stresses in the East China Sea are in good correlation with the local SLA and SO I. The differences of the wind fields on both sides of the divergent zone of the atmospheric circulation lead to the differences between the low-frequency components of the mean SLA and the zonal wind anomalies on both sides of the sea The correlation is different (the sea area south of 30 ° N is negatively correlated and the Yangtze Estuary is positively correlated). After the coordinate system is rotated, the direction of the wind stress with the greatest correlation with the local sea level anomaly is obtained. The low-frequency component analysis of the wind stress anomaly u between the SLA and the new coordinate system shows that the wind stress anomalies in the east of the Yangtze River estuary and the south of the seas at 30 ° N have the greatest impact on the sea level, respectively, at 70 ° East and 70 ° East, twenty three. Wind stress anomalies u component and SLA, SO I low-frequency component showed a better correlation, due to the divergence zone in the atmospheric circulation in the modulation effect, resulting in 30 ° N sea area on both sides of the sea level and wind stress u to SO I The opposite is true. ENSO influences the wind field in the East China Sea through the atmospheric circulation process, and the local wind field modulates the interannual variation of the East China Sea sea level by zonal wind stress. Therefore, ENSO can affect the sea level of the East China Sea by wind stress.