Monitoring of ocean environmental changes under influence of cyclonic system: Utilization of SARAL and contemporary satellite observations

Abstract

The landfall of cyclone, Hud-Hud has created a widespread destruction along the coastal regions of northern Andhra Pradesh and southern Odisha, India. The changes have also been observed in the surrounding ocean. Satellite derived ocean geophysical products are used to study the changes. SARAL, the Ka band altimeter on path 438 of 10 October 2014 along with Jason-2 altimeter on path 116 of 12 October 2014 for their along track segments in the Bay of Bengal are studied. SARAL passed a day before its landfall has captured the cyclonic event in its full intensity in their geophysical products. The changes are observed in the Inverted Barometric Pressure Correction (IBPC) by an increase of about a centimeter in coastal waters than those of far off ocean. Increase in surface winds towards the coast from 4.01m/s to 15.52m/s has been observed in the along track data. The significant wave height is also increased from about 1m to 6.43m in the affected area. The contemporary Ku band altimeter, Jason-2 has also shown similar changes in the affected area. Sea Surface Height Anomaly (SSHA) spatial distribution has remained negative along the track under the cyclone foot print. While, Advanced Scatterometer (ASCAT) on 10 October 2014 have shown strong winds (up to 22.7m/s) in the region. This has induced surface mixing and upwelling in the water column leading to cooling of surface waters and enhancement of nutrients in the surface layers. This has lead to higher primary productivity, which is observed in the ocean chlorophyll-a maps. The environmental change in the Bay of Bengal during the cyclonic event has been studied using multiple satellite datasets and drifting buoy observations.