The Impact of Locally-tuned Chlorophyll-a Algorithm in Malacca Straits

摘要

Study of biological production such as Chlorophyll-a concentration (Chl-a) is essential for sustaining ocean biodiversity and this can be undertaken by remote sensing that has advantages of synoptic area coverage, durable and continuous observation cycle and less manpower required. Space-borne optical sensor offers the application of ocean colour to estimate the Chl-a. The sought-after ocean colour algorithm designed for Moderate Resolution Imaging Spectroradiometer (MODIS) called OC3M has encountered an overestimation Chl-a issue particularly to derive the Chl-a estimate in the shallow ocean depth. This is a case for Malacca Straits and yet from the previous study, we have devised the locally tuned OC3M to minimize the overestimated Chl-a. This paper discusses about the impact of the locally-tuned Chl-a algorithm in the dual-case classification of water (known as case-1 and case-2). This study also presents the locally-tuned OC3M application on the latest reprocessed MODIS data that was launched in early 2013. We found that the second version of MODIS reprocessed data finally conveys promising and better Chl-a estimation over the Malacca Straits area. The study anticipates the locally-tuned Chl-a variant as an alternative to the standard OC3M and it requires long-term validation with massive testing points.