最近21年厄加勒斯反曲的变化

Changes of Agulhas Retroflection in Recent 21 Years

非洲南部厄加勒斯泄漏过程将印度洋的暖咸水输入大西洋,是大洋环流中联系印度洋和大西洋的关键过程,厄加勒斯反曲的位置和强度影响此泄漏过程。文章利用1993—2013年绝对海表高度数据来确定厄加勒斯环流反曲点、厄加勒斯流和回流的位置,发现厄加勒斯流和回流所在的位置年际变化较小,而厄加勒斯环流反曲点位置则年际变化显著;厄加勒斯环流反曲点位置的纬向变动范围为14°E^19°E,经向为38.5°S^40°S,东西向变化范围较大。反曲点位置与厄加勒斯流强度的相关分析表明,厄加勒斯流增强(减弱),反曲点位置偏西(东)。

Agulhas leakage on the south of Africa transports warm salt water from the Indian Ocean to the Atlantic Ocean which is the pivotal process to connect these two oceans.Meanwhile,the position and strength of Agulhas retroflection have an impact on Agulhas leakage.This paper determines the position of Agulhas retroflection point and the spatial position of Agulhas Current and Agulhas Return Current with absolute sea surface height data from 1993 to 2013.Spatial distribution of Agulhas retroflection structure shows that the positions of Agulhas Current and Agulhas Return Current change little;however,there is a significant variation in the position of Agulhas retroflection.The position of Agulhas retroflection point is in the range of 14°E-19°E and 38.5°S-40°S.The points of Agulhas Retroflection are with an oscillating change year by year.It changes little on north-south direction,but shifts significantly on east-west direction.The correlation analysis of the position of Agulhas Retroflection point and the intensity of Agulhas Current shows that strengthen of Agulhas Current makes the retroflection point shifts westward.In recent 21 years,position of Agulhas Retroflection point and westerlies have no significant correlation.