Analysis of Pre- and Post-Monsoon Suspended Sediments in the Gulf of Kachchh, India Using Remote Sensing

TL;DR

This study analyzes satellite data to understand sediment dynamics in the Gulf of Kachchh during pre- and post-monsoon periods, highlighting tidal influences and minimal monsoonal impact, with suggestions for improved future remote sensing methods.

Contribution

It provides a detailed analysis of sediment variations using satellite data during different monsoon periods, emphasizing tidal effects and proposing enhanced resolution data for future research.

Findings

Tidal changes significantly influence suspended sediment concentrations.

Pre-monsoon periods show higher sediment levels than post-monsoon.

Minimal monsoonal impact observed, with sediment mainly from the Indus River during pre-monsoon.

Abstract

A comprehensive study of satellite-derived suspended sediment concentration (SSC) during pre- and post-monsoon has been conducted with full-month cycles of tidal responses to study the suspended sediment dynamics in the Gulf of Kachchh. Tidal data were interpreted in conjunction with the OCEANSAT-1 ocean color monitor (OCM)-derived SSC for pre- and post-monsoon. The analysis of the data shows that the Gulf is predominantly affected by the tidal changes. The average SSC during pre-monsoon were 30.8 mg/l (high tide) and 24.1 mg/l (low tide); and during post-monsoon 19.7 mg/l (high tide) and 21.8 mg/l (low tide). The only little monsoonal influence is seen when Indus River discharges sediments during pre-monsoon due to increased sediment flux from its origin, Himalayas in spring (February-April) as compared to less sediment discharge observed during winter (November-December). The pre-monsoon SSC images show overall high suspended sediments whereas post-monsoon SSC images show comparatively low SSC. The use of enhanced resolution ocean color satellite data (<360 m spatial resolution) for deriving higher SSC (>40 mg/l) for moderate/normal/high monsoon years under similar tidal conditions, and for quantifying sediment dispersal and dynamics and its validation is suggested as a future avenue of research.