Decadal Spatiotemporal Halocline Analysis by ISAS15 Due to Influx of Major Rivers in Oceans and Discrepancies Illustrated Near the Bay of Bengal

Kashif Iqbal,Shengchun Piao,Minghui Zhang

doi:10.3390/w12102886

Abstract

The discharge from rivers is one of the major factors of regional salinity perturbations in addition to precipitation, evaporation, and circulation of the ocean, whereas simulations regarding the marine environment are dominantly affected by ocean salinity. Moreover, perturbations in the timing and quantity of freshwater cause salinity fluctuations, which in turn, affect the communities of both plant and fauna. In this regard, the study ingeniously employs In Situ Analysis System-15 (ISAS15) data, which is freely available online, to ascertain the salinities in proximity of the major rivers around the globe. Such computations are multilayered, i.e., for 1, 3, 5, and 10 m, and conducted along major freshwater influxes, i.e., the Amazon River, Bay of Bengal (BoB), and Yangtze River, on decadal scales, i.e., in 2004 and in 2014. Depending upon the location and availability of ISAS-15 data, the area in proximity of the Amazon is analyzed horizontally, vertically, and obliquely, whereas the areas in proximity of the BoB and Yangtze estuary are analyzed vertically and obliquely. Similarly, the study analyzed the freshwater influx at the aforementioned locations both for the maxima and minima, i.e., during the particular months that observed the maximum and minimum influx into the ocean from the above-mentioned freshwater sources in 2004, as well as in 2014. The detailed analysis proved the outcomes to be conforming with the documented literary data along the Amazon and Yangtze estuaries. However, the computed analysis illustrated the anomalous values in proximity of the BoB. The study proceeds to discuss an ingenious approach of computing, as well as extrapolating, the salinities, temperatures, and sound speed profiles (SSPs) by employing in situ deep Argo data in order to counter such anomalies, as well as conjoin it with ISAS data, to investigate such regions with broader spatiotemporal capabilities for the future course of action. For this particular study, this method is employed on certain Argo buoys in order to prove the efficacy of the aforementioned novel approach.

Highlights

The estuary’s salinity perturbation is responsible for a distinctive and elementary role in constructing spatial patterns of biota, physical characteristics, and certain biogeochemical procedures
The In Situ Analysis System-15 (ISAS15) datasets are employed for this particular study, which analyzes the halocline at three locations, i.e., Amazon river influx in the Atlantic Ocean, the Bay of Bengal (BoB) near Bangladesh’s rivers influx, Yangtze River’s influx in the East China Sea
The study ingeniously employs the datasets of ISAS15 to ascertain the freshwater into the respective seas

Summary

Introduction

The estuary’s salinity perturbation is responsible for a distinctive and elementary role in constructing spatial patterns of biota, physical characteristics, and certain biogeochemical procedures Such salinity variations are caused by the influx of freshwater into the sea among other reasons such as precipitation, evaporation, and circulation of the ocean. In order to ascertain temporal weather fluctuations relying on seasonal to decadal perturbations, an array of 3000 floats offering vertical profiles of CTD (Conductivity, Temperature, and Depth) in global oceans to the depths of 2000 m in almost real-time was proposed by the end of the previous century and was named the Argo Array The connectivity of this array with other networks was proposed in order to offer a weather observing model on a global scale.

Methods

Results

Conclusion