黑潮延伸区的海平面异常和中尺度涡的统计分析

SEA LEVEL ANOMALY AND MESOSCALE EDDIES IN THE KUROSHIO EXTENSION REGION

利用1993～2004年卫星高度计TP/Jason-1和ERS/ENVISAT提供的海平面异常(SLA)融合数据,分析了黑潮延伸区12年来的平均海平面异常的变化特征及中尺度涡的分布规律。研究表明,在黑潮延伸区海平面异常(SLA)呈递增趋势,年平均上升率为8.89mm/a,显著性周期是1年、0.5年和6年;黑潮延伸区的海平面异常和海表面温度异常的低频分量与Nino3指数具有较高的相关性。这说明,黑潮延伸区的海平面变化和海表面温度与厄尔尼诺事件密切相关,都受到黑潮变化的密切影响。在日本东部的黑潮延伸区,中尺度涡自东向西移动,寿命约为1年,移动速度大约是10经度/年。气旋涡和反气旋涡的面积呈现几乎同步增减的规律,均呈年周期变化,上半年少,下半年多。在1997～1998年,黑潮延伸区内中尺度涡的面积显著减小,并且正好对应于Nino3指数极大值出现的年份。因此,黑潮延伸区内中尺度涡的数量和强度也与厄尔尼诺事件密切相关。

The characteristics of sea level anomaly （SLA） and mesoscale eddies during 1993- 2004 year in the Kuroshio extension region are analyzed using altimetry data detected by TP/ Jason-1 and ERS/ENVISAT. It is found that the mean sea level anomaly of Kuroshio extension region in this period has a linear raise with a rate of 8.89mm/a, and has the most significant period with 1 year.0.5 year and 6 years. The correlation between the low-frequency components of SLA/SSTa in the Kuroshio extension region and Nino3 index is high, which indicates that SLA/SSTa in the Kuroshio extension region is closely related with the E1 Ni o event, and are both remarkably affected by the Kuroshio. In the ocean east of Japan, the mesoscale eddies moved from east to west with a life time of about 1 year, and a longitudinal speed in about 10 degrees/year. Clockwise eddies and anti-clockwise eddies nearly occupy even area, which fluctuates with a period of one year, reaches a minimum during the first half year and a maximum during the latter half year. In 1997-1998, the mesoscale eddies in the Kuroshio extension region decreased evidently; meanwhile the maximum appeared in the low-frequency components of Nino3 index. Therefore, The number and intensity of mesoscale eddies, in the Kuroshio extension region, are closely related with the E1 Nino phenomena.