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[Ｂ−７.４　Study on modeling temporal and spatial variation of partial pressure of CO₂ in the North Pacific utilizing data from ship-of-opportunity observation]

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[Total Budget for FY1996-2000]

　65,415,000 Yen
　(FY 2000; 14,461,000 Yen)

［Abstract］

　The ocean surface pCO₂ data set obtained by the ship-of-opportunity observation program by National Institute for Environmental Studies (NIES) utilizing cargo ships in the North Pacific was analyzed. The seasonal functions of ΔpCO₂ (pCO₂ difference of ocean and atmosphere) was obtained for each oceanic grid and monthly North Pacific ΔpCO₂ distribution maps were created. The seasonality of ΔpCO₂ showed significant difference for the region. March maximum and September minimum were observed in the subarctic Northern Western Pacific and Bering Sea. The summer decrease of pCO₂ is due to the biological production and increase in winter to the vertical mixing. Mid latitude North Pacific showed May maximum and November minimum, which has larger effect of seawater temperature change. Except for the north margin of the North Pacific is the net sink of atmospheric CO₂. The combination of the ocean surface wind data set by satellite observation and the maps obtained in this study gave an estimation of the CO₂ flux of 0.24GtC/y over the North Pacific, north of 34瀘. The relationship between pCO₂ seasonality and nutrient concentration, which was also observed by the ship-of-opportunity program, were analyzed to characterize the biological productivity in the North Pacific.

［Key Words］

　CO₂, partial pressure in seawater, North Pacific, time series measurement