Influence of the freshwater plume dynamics and the barrier layer thickness on the CO2 source and sink characteristics of the Bay of Bengal

Sea-surface pCO2 maps for the Bay of Bengal based on advanced machine learning algorithms

“…The Ganges-Brahmaputra river system, the second largest river system in the world, brings in high freshwater along with organic pollutants into the BoB region 13 , 14 . The freshwater influx increases stratification and reduces the vertical mixing (thick barrier layer), which influences the absorption and/or outgassing of atmospheric CO 2 in BoB 15 . The nutrients brought down by these rivers decrease the ocean-surface p CO 2 in the offshore region, but its influence diminishes away from the coast 14 .…”

“…This results in low sea-surface p CO 2 (≈ 320 μ atm) values during this period. The freshwater plume spread due to this southward motion of EICC results in low sea-surface p CO 2 values in the northern BoB 15 . The spatial pattern of the sea-surface p CO 2 is dominated by the biological and thermal mechanisms 14 , 18 .…”

Variability in Sea Surface pCO2 and Controlling Factors in the Bay of Bengal Based on buoy Observations at 15°N, 90°E

“…It also receives a high influx of freshwater from rivers and precipitation (Sengupta et al., 2006; Sridevi and Sarma., 2021). This high freshwater influx and the seasonally reversal monsoon winds affect the physical characteristics and consequently the carbonate dynamics (Chakraborty et al., 2021; Joshi et al., 2021). This leads to high spatial and temporal variabilities in sea surface salinity (SSS) (Joshi et al., 2021) and brings in nutrients which leads to challenges in modeling carbonate system parameters [pCO 2sea , dissolved inorganic carbon (DIC), total alkalinity (TA), and pH] for the bay (Joshi et al., 2020; Sarma et al., 2013; Sridevi and Sarma, 2021; Valsala & Maksyutov, 2010).…”

“…This high freshwater influx and the seasonally reversal monsoon winds affect the physical characteristics and consequently the carbonate dynamics (Chakraborty et al., 2021; Joshi et al., 2021). This leads to high spatial and temporal variabilities in sea surface salinity (SSS) (Joshi et al., 2021) and brings in nutrients which leads to challenges in modeling carbonate system parameters [pCO 2sea , dissolved inorganic carbon (DIC), total alkalinity (TA), and pH] for the bay (Joshi et al., 2020; Sarma et al., 2013; Sridevi and Sarma, 2021; Valsala & Maksyutov, 2010). Both observation and model based studies have shown low pCO 2sea in the northeastern BoB and high pCO 2sea in the southern region (Joshi & Warrior, 2022; Joshi et al., 2021; Sarma et al., 2018).…”

“…This leads to high spatial and temporal variabilities in sea surface salinity (SSS) (Joshi et al., 2021) and brings in nutrients which leads to challenges in modeling carbonate system parameters [pCO 2sea , dissolved inorganic carbon (DIC), total alkalinity (TA), and pH] for the bay (Joshi et al., 2020; Sarma et al., 2013; Sridevi and Sarma, 2021; Valsala & Maksyutov, 2010). Both observation and model based studies have shown low pCO 2sea in the northeastern BoB and high pCO 2sea in the southern region (Joshi & Warrior, 2022; Joshi et al., 2021; Sarma et al., 2018). Significant temporal variations of pCO 2sea with high values during the southwest monsoon and low values during the northeast monsoon season were observed (Chakraborty et al., 2021; Joshi & Warrior, 2022).…”