Observation of Algal Bloom in the Northwest Arabian Sea Using Multisensor Remote Sensing Satellite Data

Abstract

Algal bloom observed using Indian Remote Sensing Satellite IRS-P4 Ocean Color Monitor (OCM) derived chlorophyll images during December 23, 2003–January 8, 2004, off the Oman coast. High chlorophyll concentration (∼20 mg m⁻³) patches were observed. MODIS-Aqua data of January 1, 2004, were analyzed to generate normalized water leaving radiance (nLw) images for seven visible channels: 412, 443, 488, 531, 551, 667 and 678 nm. The channels 667 and 678 nm showed interesting algal bloom features. The bloom features were detected in OCM image of January 2, 2004, using Subramanian's Trichodesmium detection Protocol. MODIS-Aqua retrieved Sea Surface Temperature (SST) around the bloom patches was observed to be >240°C. The OCM chlorophyll mean observed to be very high (>10.0 mg m⁻³) in two bloom pockets. Quickscat scatterometer derived wind speed was found to be optimum in the range of 3–5 m/sec.

Keywords:

• Algal bloom
• remote sensing
• northwest Arabian Sea
• chlorophyll
• wind
• SST

Acknowledgements

The author is thankful to Dr. R.R. Navalgund, director, Space Applications Center, for providing necessary guidance and facilities for carrying out the work. The AVHRR SST and Quickscat wind vector data archived from PO.DAAC, JPL/NASA is sincerely acknowledged. Thanks to anonymous reviewers for their critical comments to improve the manuscript.