The Relationship between Sea Surface Temperature and Chlorophyll-A Concentration in Coastal Sea Upper Gulf of Thailand

Abstract

Studies of the relationship between sea surface temperature (SST) and chlorophyll-a (Chl-a) concentrations contribute to the support of monitoring and assessment of the marine environment. Chlorophyll-a is an indicator of phytoplankton abundance and biomass in coastal water sources, while sea surface temperature is one of the factors influencing the growth of phytoplankton. Therefore, monthly satellite imagery data is used, which is product data level 3, through geometric correction and projection system, providing a spatial resolution of 4.6 kilometers from the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite for the period 2015-2022 was used to create monthly climate average data from that period 8 years to find relationships and to observe temporal and spatial changes in the coastal sea the upper Gulf of Thailand. From the results of the study of the changes according to the months and the monsoon period, it was found that since January, the sea surface temperature gradually increased and the average maximum temperature was in May, then the temperature began to decrease. While the chlorophyll concentration was highest in September. The annual monthly averages of sea surface temperature and chlorophyll concentrations show a positive relationship during the northeast monsoon and a negative relationship during the southwest monsoon. It has statistical significance at the 0.01 level with the influence of monsoon winds. In addition, during the southwest monsoon, there was upwelling. Which carries cold water masses and nutrients from deep water to the sea surface, influencing the concentration of chlorophyll and the sea surface temperature decreased.