Summary of Abstract Submission

Abstract Submission No. IO50-06-0027PresentationPoster

INDIAN OCEAN ACIDITY, VARIABILITY AND TRENDS

Vinu Valsala*1, Raghu Murtugudde2, Yogesh Tiwari1, Roxy Mathew Koll1, Sabu. P.3, Anil Kumar3

1 IITM, Pune, India
2 University of Maryland, USA
3 NCAOR, Goa, India

ABSTRACT :

Atmospheric concentrations of greenhouse gases, especially CO2 is increasing at an alarming rate. Nearly a quarter of the total man-made CO2 in the atmosphere has been dissolved to the ocean by solubility and biological export. This gradual dissolution of CO2 into the ocean also causes the ocean to be more and more acidic over the time. The acidity (measured as the pH of the surface ocean) is reported to be trending as understood by the analysis of available observations in the previous studies. In this study we examine the various factors that affects the Indian Ocean acidity, its variability and trend. Four factors are hypothesized to affect Indian Ocean acidity trends and they are (a) the trend due to direct dissolution of CO2 from the atmosphere, (b) trend due to the large scale circulation changes in the ocean and (c) trend due to the SST warming and shift in the equilibrium of carbonate chemistry of Indian Ocean and (d) trend in pH due to the carbonic concentrations transported to the Indian ocean from the neighboring oceans. The results indicate that the Arabian Sea is acidifying at a faster rate than the Bay of Bengal. The equatorial Indian ocean appears to have a mild increase in the acidity. The subtropical south Indian Ocean is acidifying at most intensive rate as this region is dominated by the carbon export by solubility pump. The study further goes by explaining various factors responsible for these acidity trends and their regional characteristics.