Sea surface salinity (SSS)from Aquarius during August 2011 and March 2014,together withinsitu salinitydata (e.g.Argo)are used to explore seasonal and interannual variations of the SSS in the Bay of Bengal.Itshows that Aquarius SSS has a significant positive correlation with Argo SSS.The Aquarius SSS is relatively lowerthan Argo SSS,and there exists a negative bias of —0.13 between these two data.The negative bias is larger inthe northern bay than that in the southern bay (—0.28 vs —0.10).The bias mainly comes from the differentdepth between Aquarius and Argo floats in measuring SSS.Aquarius SSS captures main seasonal variations of theSSS in the bay,such as the intrusion of saltier water from Arabian Sea and seasonal migrations of the freshwaterplumes in the northern bay.Besides,the SSS reveals anomalous salting (freshening)in the bay during the spring2011 (2012).Our results suggest that the reduced (enhanced)precipitation during the summer 2010 (2011)in thenorthern bay reduced (enhanced)freshening in that region,and the anomalous salting (freshening)water was advectedsouthward by the surface-layer circulation causing anomalous salting (freshening)in the whole bay.Meanwhile,the positive (negative)wind stress curl anomaly also contribute to the anomalous salting (freshening)eventduring spring 2011 (2012)in the bay via impacting the vertical mixing processes.%本文利用2011年8月至2014年3月Aquarius卫星盐度产品结合Argo等实测盐度资料,探讨了孟加拉湾海表盐度的季节及年际变化特征.结果显示,Aquarius与Argo盐度呈显著线性正相关,总体较Argo盐度值低,偏差为—0.13,其中在孟加拉湾北部海域负偏差值比南部海域更大,分别为—0.28和—0.10.Aquarius卫星与Argo浮标在表层盐度观测深度上的差别是造成此系统偏差的主因.Aquarius盐度资料清晰显示了孟加拉湾海表盐度具有明显的季节变化特征,包括阿拉伯海高盐水的入侵引起湾南部海域盐度的变化以及湾北部淡水羽分布范围的季节性迁移等主要特征.此外,分析还揭示了2011(2012)年春季整个湾内出现异常高盐(低盐)现象.研究表明,2010(2011)年湾北部夏季降雨减少(增加)导致该海域海水盐度偏高(偏低),并通过表层环流向南输运引起次年春季湾内表层盐度出现异常高盐(低盐)现象,春季风应力旋度正(负)距平通过影响盐度垂直混合过程对同期表层盐度异常高盐(低盐)变化也有影响.
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