Cyclone Enhanced Chlorophyll in the Bay of Bengal as Evidenced from Satellite and BGC-Argo Float Observations

Autor: Debadatta Swain, T. V. S. Udaya Bhaskar, J. Pavan Kumar, Chiranjivi Jayaram
Rok vydání: 2019
Předmět:
Zdroj: Journal of the Indian Society of Remote Sensing. 47:1875-1882
ISSN: 0974-3006
0255-660X
DOI: 10.1007/s12524-019-01034-1
Popis: Temporal evolution of biophysical properties of Bay of Bengal (BoB) was measured using an Argo float equipped with fluorescence sensor (BGC-float) during the winter monsoon of 2013–2014. This season was subjected to intense vertical mixing due to the passage of several cyclonic storms beginning with ‘Phailin’ in October to ‘Madi’ in December 2013. These events had resulted in anomalous chlorophyll bloom (> 0.9 mg/l) together with an increase of ~ 1 PSU in the surface salinity and a drop-in temperature (~ 1 °C) in the southwestern BoB. The event was well captured by a BGC-float (WMO ID 2902086) present in the region close to the tracks of cyclones ‘Leher’ and ‘Madi’. The presence of a strong cold-core eddy as observed from the sea level anomaly data played a vital role in spreading the bloom over a wider area and maintaining it for nearly two months from November 2013 to January 2014. This was also evident from the satellite observations of surface chlorophyll-a concentration and Ekman pumping velocity (~ 2 × 10–3 m/s). The intense mixing caused by the cyclonic storms has resulted in eroding the stratification and assisting the entrainment of nutrients into the euphotic layer, which was subsequently sustained by the mesoscale eddy. The present study reveals the strong synergistic application potential of BGC-float data together with satellite observations in monitoring the changes in the vertical structure of chlorophyll during the cyclonic storms and other mesoscale processes.
Databáze: OpenAIRE
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