CO₂ exchange at air-sea interface in the Huanghai Sea

During the Huanghai Sea Circulation and Material Flux Expedition in Spring 1996,f_CO2 in surfacewater and atmosphere was measured.The f_CO2 in surface water varied in a range from 220 to 360μatm¹⁾ while atmospheric concentration was nearly constant at 360 μatm, showing that the Huanghai Sea surface waters were undersaturated with respect to atmospheric CO₂ during the time of investigation.A model was developed in this study in order to estimate the CO₂ flux at the air-sea interface.The model incorporates the time-series variations of the distributions in SST (sea surface temperature),salinity, mixed-layer depth, atmospheric f_CO2,gas-transfer velocity, and CZCS chlorophyll concentration in the Huanghai Sea and was calibrated with the observed fez data.The primary parameter affecting fez in surface water is the variation of SST through time.The annual fluxes of CO₂ are estimated as 0.033 Gt C from the sea into the atmosphere and 0.044 Gt C from the air into sea.The Huanghai Sea, thus behaves as a CO₂ sink absorbing 0.011 Gt C of CO₂ a year, which.corresponds to about 0.5% of global oceanic absorption capacity.