太平洋中低纬海水中的二氧化碳分布特征及其与海洋环境条件的关系

Distribution of marine carbon dioxide and its relationship with other marine parameters and air-sea anomalies

根据1986年11月至1990年6月进行的中美热带西太平洋海-气相互作用(TOGA)联合考查和1995年10月至1996年6月“中日副热带联合调查”期间获得的14个航次大气和海水CO2的观测资料,给出了主要观测海区CO2的源与汇的分布特征:在赤道地区5°N^5°S,130°~165°E观测到的表面水中二氧化碳分压的值超过了大气中二氧化碳分压1.5~4.5 Pa,结果表明该海区对大气CO2而言是源,但是该值远小于在中赤道测到的+9.1 Pa和在东赤道太平洋所测的+15 Pa的值.由此表明热带太平洋CO2源的强度是向西减弱的.副热带海区在秋季对大气CO2而言是较强的源,春季是汇.对影响海水CO2变化的主要因素温度、盐度等进行了讨论,表明CO2的分布变化直接受海流、水团、黑潮和ENSO事件影响.

During “TOGA” and “China-Japan joint investigation of the subtropical circulation”, the total dissolved carbon dioxide in surface and deep water and sea-air partial pressure of carbon dioxide in surface and deep water were measured in November 1986 and June 1996 with the coulometer and gas chromatography systems. The distribution and variation of the sources and sinks of carbon dioxide on the basis of the data of carbon dioxide partial pressure value in air （A） and carbon dioxide partial pressure value in the surface water were measured during the 14 cruises “TOGA” and “China-Japan joint investigation of the subtropical circulation”. The carbon dioxide partial pressure value in the surface water observed over the equatorial area,5°N～5°S,130°～165°E, exceed the carbon dioxide partial pressure value in air by 1.5 to 4. 5 Pa, indicating that in this area there is a source of atmospheric carbon dioxide. These values are much smaller than those of up to ＋9.1 Pa observed in the central equatorial Pacific and those of up to ＋ 15 Pa observed in the eastern equatorial Pacific. It appears, therefore, that the intensity of the oceanic carbon dioxide source decreases westward. In autumn there is a stronger source and in spring there is a sink for atmospheric carbon dioxide, in the subtropical circulation. On the basis of nine cruises of carbon dioxide data in surface and deep water measured, major factors temperature and salinity influencing carbon dioxide in seawater were discussed, the distribution and variation of carbon dioxide may be related to the current, water mass, Kuroshio and ENSO.