The investigation of thermal fronts variability and its linkage to chlorophyll-a concentration in the Southeastern Tropical Indian Ocean Rangga Amrullah (a), Rahaden Bagas Hatmaja (b), M Restu Putra Sugianto (a), Shinta Ayu Kusumaningrum (a)
a) Marine Science Study Program, Faculty Of Fisheries and Marine Science, Universitas Padjadjaran
Jl. Raya Bandung Sumedang KM.21, 45363 Kabupaten Sumedang
b) Research Centre for Climate and Atmosphere, National Research and Innovation Agency
Jl. Dr. Djunjunan No.133, Pajajaran, 40173 Kota Bandung, Indonesia
Abstract
The spatial and temporal variability of the thermal fronts and their relationship with chlorophyll-a in the Southeastern Tropical Indian Ocean was studied using time series of MODIS daily Sea Surface Temperature (SST) and chlorophyll-a concentration (CHL) to investigate the locations of intense fish catch activities. An edge-detection algorithm operated on each SST image to identify thermal fronts in which a gradient of 0.3 C/pixel (∼- 0.02 C/km) was chosen following the sensitivity analysis. This study shows persistent and coherent spatial features between the datasets in their climatology and seasonal cycles. They exhibit distinct locations of maxima co-occurring between the 10 and 50 m isobaths in the continental shelf and slope region coincided with the areas of the VIIRS mapped fishing vessels cluster sites. The annual frequency dominates the seasonal cycles of thermal front density with a positive phase during May to November and peaks in September. These locations with a high probability of thermal fronts and high concentrations of Chlorophyll-a can be considered as the perennial potential fishing zone, with the boreal summer season being a more favorable period for fishing.
Keywords: Thermal Front, Threshold, SIED, Potential Fishing Zone
