The Gulf of Thailand is a semi-closed Gulf on the west and southwest side of the Indochina Penisula and experiences reversal monsoon. The object of the present study is to investigate monthly and spatial distributions of the phytoplankton in the Gulf of Thailand during whole El Nino year 2002 by using remote-sensing measurements of chlorophyll-a (Chl-a) and surface wind vectors. | VNU Journal of Science Earth and Environmental Sciences Vol. 34 No. 2 2018 22-27 Effects of Monsoon Activity on Monthly Phytoplankton Blooms in the Gulf of Thai Land in El Nino Year 2002 Le Van Thien Hanoi University of Natural Resources and Environment Cau Dien Nam Tu Liem Hanoi Vietnam Received 19 March 2018 Revised 14 April 2018 Accepted 18 April 2018 Abstract The Gulf of Thailand is a semi-closed Gulf on the west and southwest side of the Indochina Penisula and experiences reversal monsoon. The object of the present study is to investigate monthly and spatial distributions of the phytoplankton in the Gulf of Thailand during whole El Nino year 2002 by using remote-sensing measurements of chlorophyll-a Chl-a and surface wind vectors. Results show that monthly and spatial variations of the phytoplankton blooms are primarily associated with the monsoonal winds. In general the average monthly Chl-a concentrations were quite low . Thien VNU Journal of Science Earth and Environmental Sciences Vol. 34 No. 2 2018 22-27 23 variations of Chlorophyll-a Chl-a and sea surface wind conditions in the Gulf of Thailand during the whole El Nino year 2002 by examining satellite measurements. 2. Study area and satellite data and methods . Study area The study region is the Gulf of Thailand area in Fig. 1 1000E 1040E 60N 120N . The average depth of Gulf of Thailand is about 40m. This region experiences reversal monsoons with the southwest monsoon in the summer and northeast monsoon in the winter. Figure 1. Bathymetry of the study area. . Satellite-derived chlorophyll-a Sea viewing Wide Field-of View Scanner SeaWiFS derived Chlorophyll-a was processed using the Ocean Color 4-band algorithm OC4 5 6 . Monthly averaged Chl- a concentrations with 3x3km spatial resolution were obtained and processed for the study region. Ocean Color and Temperature Scanner OCTS aboard Advanced Earth Observing Satellite observed the Chl-a concentration in the surface layer from October 1996 to .
