VARIABILITY OF ATMOSPHERIC CO₂ OVER INDIA AND SURROUNDING OCEANS AND CONTROL BY SURFACE FLUXES

Abstract. In the present study, seasonal and inter-annual variability of atmospheric CO₂ concentration over India and surrounding oceans during 2002–2010 derived from Atmospheric InfrarRed Sounder observation and their relation with the natural flux exchanges over terrestrial Indian and surrounding oceans were analyzed. The natural fluxes over the terrestrial Indian in the form of net primary productivity (NPP) were simulated based on a terrestrial biosphere model governed by time varying climate parameters (solar radiation, air temperature, precipitation etc) and satellite greenness index together with the land use land cover and soil attribute maps. The flux exchanges over the oceans around India (Tropical Indian Ocean: TIO) were calculated based on a empirical model of CO₂ gas dissolution in the oceanic water governed by time varying upper ocean parameters such as gradient of partial pressure of CO₂ between ocean and atmosphere, winds, sea surface temperature and salinity. Comparison between the variability of atmospheric CO₂ anomaly with the anomaly of surface fluxes over India and surrounding oceans suggests that biosphere uptake over India and oceanic uptake over the south Indian Ocean could play positive role on the control of seasonal variability of atmospheric carbon dioxide growth rate. On inter-annual scale, flux exchanges over the tropical north Indian Ocean could play positive role on the control of atmospheric carbon dioxide growth rate.