Analysing Sea Surface Temperature and Chlorophyll-a Distribution Along Visakhapatnam Coast Using MODIS Data

Abstract

Satellite images along with Geographic Information Systems (GIS) are indispensable instruments for the identification, monitoring, and analysis of environmental transformations and management. The primary focus of this study is to investigate the relationship between Sea Surface Temperature (SST) and Chlorophyll-a concentration in the Bay of Bengal along the Visakhapatnam Coast by utilizing MODIS data. The research utilized remote sensing methodologies to accumulate data on SST and Chlorophyll-a concentration from the MODIS Aqua satellite, which provided daily observations for the period of January to December 2022. The investigation has unveiled important findings indicating a strong correlation between SST and Chlorophyll-a concentration, in general, higher SST levels are found to be linked with lower Chlorophyll-a concentrations, and conversely. The majority of months demonstrated notable determination coefficient (r2), except July, August, September, and October, wherein weaker correlations were observed due to increased precipitation levels in these specific months. Specifically, the determination coefficients were as follows: r2 = -0.58, -0.38, -0.35, -0.61, 0.16, -0.25, -0.06, and -0.59, with the exceptions being July (r2 = 0.01), August (r2 = 0.19), September (r2 = 0.33), and October (r2 = 0.24). Additionally, seasonal fluctuations were evident, with increased SST levels and reduced Chlorophyll-a concentrations during the summer season, and decreased SST levels and heightened Chlorophyll-a concentrations during the monsoon period. To effectively conclude, extensive research utilizing MODIS data has revealed significant trends and relationships between SST and Chlorophyll-a concentrations over the Bay of Bengal along the Visakhapatnam Coast. SST has been observed to increase significantly over recent decades, while Chlorophyll-a concentrations peak during the northeast monsoon season and decline during the southwest monsoon. A robust inverse correlation exists between SST and Chlorophyll-a concentrations, indicating that elevated SSTs are associated with decreased Chlorophyll-a levels, with exceptions during periods of heightened precipitation. Seasonal fluctuations further emphasize the dynamic nature of these parameters, with implications for marine ecosystem management and conservation efforts in the face of climate change, overfishing, and pollution. Remote sensing remains a crucial tool for monitoring these variables and understanding the marine ecosystem's dynamics in the Bay of Bengal.