Bio-optical characterization using Ocean Colour Monitor (OCM) on board EOS-06 in coastal region

TL;DR

This paper discusses the use of the Ocean Colour Monitor (OCM) on EOS-06 for coastal ocean colour remote sensing, focusing on atmospheric correction challenges and the sensor's capabilities in complex waters.

Contribution

It introduces the OCM-3 sensor onboard EOS-06, highlighting its spectral bands and potential for improved ocean colour monitoring in optically complex coastal waters.

Findings

OCM-3 has 13 VNIR bands suitable for coastal monitoring.

Atmospheric correction is challenging in sediment-laden waters.

Study demonstrates geophysical product retrieval in the Arabian Sea.

Abstract

In ocean colour remote sensing, radiance at the sensor level can be modeled using molecular scattering and particle scattering based on existing mathematical models and gaseous absorption in the atmosphere. The modulation of light field by optical constituents within the seawater waters results in the spectral variation of water leaving radiances that can be related to phytoplankton pigment concentration, total suspended matter, vertical diffuse attenuation coefficients etc. Atmospheric correction works very well over open ocean using NIR channels of ocean colour sensors to retrieve geophysical products with reasonable accuracy while it fails over sediment laden and/or optically complex waters. To resolve this issue, a combination of SWIR channels or NIR-SWIR channels are configured in some ocean colour sensors such as Sentinel- OLCI, EOS- 06 OCM etc. Ocean Colour Monitor (OCM)-3 on board EOS -06 was launched on Nov 26, 2022. It has 13 bands in VNIR (400-1010 nm range) with ~1500 km swath for ocean colour monitoring. Arabian Sea near Gujarat coast is chosen as our study site to showcase the geophysical products derived using OCM-3 onboard EOS-06.