SPATIO-TEMPORAL DISTRIBUTION OF CARBON DIOXIDE PARTIAL PRESSURE IN THE BAY OF BENGAL

Sea water carbon dioxide partial pressure is the major controlling factor in the air-sea CO2 gas exchange. The seasonal and spatial distribution of Carbon Dioxide Partial Pressure (pCO(2)_sw) is vastly regulated by the physical, chemical and biological parameters of the ocean whereas alterations in the atmospheric pCO(2) is minimal. Although the global ocean is a net CO2 sink, regional fluctuations in the CO2 partial pressures can have potential consequences on the universal trend. Being one of the least sampled oceanic region, the chief elements regulating the Bay of Bengal (BoB) partial pressures are yet to be understood. An attempt has been made to analyse the significance of biological and chemical properties in defining the spatial distribution of the sea surface partial pressures as well as the influence of monsoonal river influx in BoB. Results revealed an equal importance of the chemical and biological factors on the partial pressure distribution. The Multiple Linear Regression (MLR) and Support Vector Regression (SVR) algorithms developed from Sea Surface Salinity (SSS) and Sea Surface Temperature (SST) showed to give better output in the post monsoon, while they tend to underestimate the values in the pre-monsoon season due to interference by biological factors. A strong influence of the fresh water discharge on the surface salinity was observed which in turn has implications on the spatial distribution of sea water partial pressures where the pre-monsoon value range of 400-430 mu atm was decreased to 386-417 mu atm range in the post monsoon.