ENSO,火山活动与大气CO_2的年际变化

ENSO, Volcanic Activities and Interannual Variations of Atmospheric CO_2

利用大气CO2及其δ13C的观测数据分析了不同区域大气CO2的季节和年际变化特征,并结合δ13C的变化趋势判断大气CO2变化的主要影响因素是来自陆地还是海洋。结果表明:大气CO2的年际变化主要受ENSO引起的陆地植被初级生产量而不是海洋吸收变化的影响,且LaNi～na对大气CO2的影响大于ElNi～no。火山活动后大气CO2的增加幅度减小,甚至掩盖了ENSO的影响,喷发后δ13C的增幅同步减小说明大气CO2增幅减小缘自温度持续降低引起的海洋吸收的增加或陆地呼吸作用的减弱。

Based on the observations of atmospheric CO2 and its δ13C, the characters of seasonal and interannual variations of atmospheric CO2 were analyzed in different regions. The trends of atmospheric δ13C were used to distinguish whether the dominative influential factor for the variations of atmospheric CO2 is from the terrestrial or the ocean. The results show that the interannual variations of atmospheric CO2 are mainly influenced by ENSOrelated change of terrestrial vegetation primary production, not by oceanic sink. And the intensity of La Nia has more effect on atmospheric CO2 than that of El Nio. The atmospheric CO2 increase would decrease after volcano events, which even conceal ENSO effects. The synchronized decrease in atmospheric δ13C increase after volcano eruptions indicates that it is likely due to the increase of oceanic uptake or the weakening of terrestrial respiration resulted from persistent decrease of surface temperature.