| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
Global warming has imposed an important impact on people activities at the present time. Carbon dioxide(CO2), one of the most important green house gases, is associated with air-sea gas exchange and global carbon circulation. The estimation of air-sea CO2 flux is very important in global carbon circulation and climate research. The flux of CO2 between the atmosphere and the ocean is estimated by the partial pressure of CO2(pCO2) difference multiplied by CO2 gas exchange coefficient which is one of the very important parameters in estimating air-sea CO2 flux. Several gas transfer models which calculates gas exchange coefficient have been proposed, but it is not easy to evaluate CO2 gas transfer models at the present time due to the difficulties of gas exchange coefficient measurement.
In this study, we developed "Air-sea carbon dioxide exchange feedback model" to describe gas exchange processes caused at the air-sea interface, which can estimate the temporal variation of pCO2 in the seawater. As a result, typical CO2 exchange coefficients had accuracy of 1% within wind speed about 7-15m/s.
Next, we analyzing the variation of the time series of the surface total CO2(TCO2) about the CO2 taken into an oceanic surface, we have made another one model of the "TCO2 variation analysis". According to this model, surface TCO2 change was able to be divided into the influence from CO2 flux from atmosphere and other influences that are the upwelling and the biological activities. In addition, we enhanced the model of the "TCO2 variation analysis" to global area. As a result, the variation of the surface TCO2 in global ocean is predominant of not air-sea CO2 flux from atmosphere and ocean, and it's value is about 2 (μmol/kg/month). In North hemisphere, it also tends to be domineering.
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