ENVIRONMENTAL MONITORING ON THE SURFACE OF THE ANDAMAN SEA OVER THE SOUTHWESTERN COAST OF THAILAND: A CASE STUDY OF SPATIAL AND TEMPORAL VARIABILITY OF CHLOROPHYLL-A

Abstract

Chlorophyll-a is a pigment or substance used in photosynthesis that is found within the cell of phytoplankton, small unicellular algae that floats in water and is blown by waves, wind, and tide. Phytoplankton is essential for the aquatic ecosystem. This research studies the spatial and temporal variability of chlorophyll-a using data from the Aqua satellite in the MODIS system from 2018 to 2022, then analyzes the data with the SeaWiFS Data Analysis System (SeaDAS) program. The results show that chlorophyll-a on the surface of the Andaman Sea varies during the year according to monsoon activity. It has a high value during the northeast monsoon (November to March), and its maximum value is in January. On average, chlorophyll-a in June 2021 had a minimum value of 0.1994 mg/m3, and chlorophyll-a in January 2022 had a maximum value of 0.8591 mg/m3. The relationship between chlorophyll-a and sea surface temperature during the northeast monsoon, including wind stream at different times, shows the increase and decrease of chlorophyll-a, which may be consistent with upwelling and downwelling at the eastern coast of the Andaman Sea.