A comparison of chlorophyll-a measurements from modis and seawifs in Terengganu waters

Abstract

The amount of chlorophyll-a depends on the amount of algae and used as an indicator of phytoplankton abundance and biomass in coastal water. The concentration of chlorophyll-a also could be a general measure of water quality. A series of Moderate Resolution Imaging Spectroradiometer (MO DIS) and Sea-viewing Wide Field-of-view Sensor (Sea WiFS) data were used in this study to investigate the amount of chlorophyll-a along Terengganu waters. The objectives of this study are to determine the chlorophyll-a concentration from satellite imageries and in-situ measurement and to compare the chlorophyll-a concentration from MOD IS and Sea WiFS. The sampling period were in 13-16 May 2009 and 6-9 July 2009, starting from Redang Island to Kapas Island. The in-situ concentration of chlorophyll-a for the first sampling ranging from 0.25 to 3.31 mg/m3 • While the second sampling ranging from 0.13 to 1.21 mg/m3 • There was a good agreement between in-situ and MOD IS chlorophyll-a concentration with R2 = 0.898. Correlation between MOD IS and Sea WiFS data over 2009 however varies from R2 = 0.018 to 0.900. This happens maybe due the presence of cloud and haze in MODIS and SeaWiFS image. This study revealed that more satellite images available for MODIS compared to SeaWiFS. This may be due to SeaWiFS satellite server problem. In a nutshell, MODIS is more likely to used for determining the concentration of chlorophyll-a compared to Sea WiFS.