Analysis of the spatio-temporal distribution of chlorophyll-a in the eastern Indian Ocean near the time of the 2004 South Asian tsunami

Abstract

This study analysed the spatio-temporal distributions of chlorophyll-a (chl-a) in the Indian Ocean during the 2004 South Asian tsunami and the effects of four variables (sea surface temperature, normalized water-leaving radiance, rainfall and wind speed) on chl-a distributions during the tsunami, using satellite data and spatial models. The results showed considerable variations in the spatio-temporal distributions of chl-a, and the effects of the four variables on chl-a around the tsunami. The results revealed that sea surface temperature and rainfall had negative effects on chl-a, while normalized water-leaving radiance and wind speed had positive effects. The effects of all the four explanatory variables were significant (positive or negative) before the tsunami. Except normalized water-leaving radiance, the other three variables all showed certain degrees of weakened effects on chl-a after the tsunami, which suggested the physical disturbance of the tsunami on the effects of these variables on chl-a distribution.