The Northern Bay of Bengal (NBOB) exhibits extreme salinity stratification caused by intense summer monsoon rainfall and associated river discharge. This accumulated fresh water plume in NBOB is believed to be transported along the East coast of India (ECI) by East India Coastal Current (EICC), known as River in the Sea (RIS). Though in situ sea Surface Salinity (SSS) measurements are sparse, the advancement of satellite monitoring system has provided a unique opportunity to unravel salient features of RIS. In the present study, in situ SSS at five selected regions around the Indian coast and open ocean are utilized to validate the Soil Moisture Active Passive (SMAP) (L3, v4.3) products. Further, this new SMAP data is used to examine year‐to‐year variability of RIS during 2015–2019 and the driving forces responsible for its existence. This SMAP SSS exhibited 1.52, 0.46, 0.38, 1.45 RMSD and 0.97, 0.82, 0.85, 0.86 correlation in NBOB1, NBOB2, Central BOB (CBOB) and Western BOB (WBOB), respectively with in situ measurements. This data also depicted the presence of “RIS” all along the ECI only during November in consistent with the magnitude of Kelvin wave induced EICC. The southward extension of RIS along the ECI is primarily based on the magnitude of remote equatorial wind induced forces. The mesoscale eddies in south‐western BOB (SWBOB) alters the shape of RIS and even inhibit its southward propagation completely.

中文翻译：

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卫星SMAP推论的赤道偏风和局部中尺度涡旋对印度东海岸“海洋河流”的存在的影响。

孟加拉北部湾（NBOB）表现出强烈的盐分分层，这是由于夏季强烈季风降雨和相关的河流排泄造成的。据信，NBOB中积聚的淡水羽流是由东印度沿海海流（EICC）沿印度东海岸（ECI）进行运输的，被称为海中河流（RIS）。尽管原位海表盐度（SSS）测量很少，但卫星监测系统的进步为揭示RIS的显着特征提供了独特的机会。在本研究中，利用印度海岸和大洋周围五个选定区域的原位SSS来验证土壤水分主动被动（SMAP）（L3，v4.3）产品。此外，此新的SMAP数据用于检查RIS在2015-2019年期间的年度变化以及造成其存在的原因。通过现场测量，此SMAP SSS在NBOB1，NBOB2，中央BOB（CBOB）和Western BOB（WBOB）中分别显示1.52、0.46、0.38、1.45 RMSD和0.97、0.82、0.85、0.86相关。该数据还描绘了仅在11月整个ECI内都存在“ RIS”，这与开尔文波诱发的EICC的大小一致。RIS沿ECI向南延伸主要是基于偏远赤道风感应力的大小。西南BOB（SWBOB）中尺度的涡流改变了RIS的形状，甚至完全抑制了其向南传播。该数据还描绘了仅在11月整个ECI内都存在“ RIS”，这与开尔文波诱发的EICC的大小一致。RIS沿ECI向南延伸主要是基于偏远赤道风感应力的大小。西南BOB（SWBOB）中尺度的涡流改变了RIS的形状，甚至完全抑制了其向南传播。该数据还描绘了仅在11月整个ECI内都存在“ RIS”，这与开尔文波诱发的EICC的大小一致。RIS沿ECI向南延伸主要是基于偏远赤道风感应力的大小。西南BOB（SWBOB）的中尺度涡旋改变了RIS的形状，甚至完全抑制了其向南传播。