Assessment of Oil Spill Pollution over the North Eastern Arabian Sea Using EOS-04 C-Band SAR Data

Abstract

The North Eastern Arabian Sea (NEAS) is one of the regions highly vulnerable to oil spill pollution due to massive shipping activity, international oil tanker routes, and oil rig operations. Recent studies have indicated that Bombay High Field, located in the NEAS, significantly contributes to oil spill pollution into the sea. This study pioneers the utilization of ISRO’s EOS-04 SAR data in assessing the oil pollution in the NEAS. We also tested the performance of various speckle filters for reducing speckle noise in the EOS-04 data with an oil spill event. We found that the Medain speckle filter performed better and additionally, demonstrated an example of EOS-04 oil-spill look-alike case over the Bombay High region. An inter-sensor comparison of EOS-04 against Sentinel-1 A is also carried out to evaluate the performance of EOS-04 in mapping the ocean features of oil spills and ships. Subsequently, a time series data of EOS-04 from March 2022 to November 2023 is used to quantitatively estimate the oil pollution due to oil leaks in each month in terms of spill area and volume. The distribution of oil pollution in terms of spreading area is high in October 2023 with 556 sq km (25.25%) and very low in August 2023 with 6.79 sq km (0.31%). During the study period, we estimated the total surface contamination of oil pollution to be 2193 sq km and oil released is around 435.35 tons. This study emphasizes the need to regularly monitoring and safeguard the marine environment from the unaccounted and unreported oil entering the Arabian Sea from the Bombay High Region.