The Impacts Of ENSO And Volcanic Activities On The Interannual Variation Of Atmospheric CO₂

The interannual variation of atmospheric CO₂ is mainly related to ENSO and volcanic activities,such a variation helps us to study the mechanisms in carbon cycle and the response of carbon cycle to climate change.It is commonly believed that ENSO and volcanic activities mainly impact the terrestrial carbon cycle.We have studied the impacts of ENSO and volcanic activities on the interannual variation of atmospheric CO2 on a global scale,here we extend the study to latitudes.Our results suggested that some ENSO events may also impact the oceanic carbon cycle significantly:the eastern tropical Pacific upwelling outgassing may be still robust during warm pool El Nino such as 1994/95El Nino;The 1997/1998El Nino not only influents the terrestrial carbon cycle,but also may influent the oceanic carbon cycle in the eastern tropical Pacific and the mid-latitude South Pacific.The decreasing of CO2 during volcanic events are mainly related to the terrestrial carbon cycle at northern high latitudes,and such a decreasing of CO₂ during 1991Pinatubo may invert the sea-air net flux at the same latitudes,this conclusion verifies the results of recent model-based studies.