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Modeling the volcanic signal in the atmospheric CO 2 record
Author(s) -
Jones Chris D.,
Cox Peter M.
Publication year - 2001
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2000gb001281
Subject(s) - carbon cycle , volcano , environmental science , atmospheric sciences , climatology , troposphere , biosphere , vulcanian eruption , carbon dioxide in earth's atmosphere , carbon dioxide , anomaly (physics) , atmospheric circulation , climate change , geology , ecosystem , oceanography , chemistry , ecology , physics , organic chemistry , condensed matter physics , seismology , biology
There is significant interannual variability in the atmospheric concentration of carbon dioxide even when the effect of anthropogenic sources has been accounted for. It has been shown that this variability is correlated with the El Nino Southern Oscillation (ENSO) cycle [ Bacastow , 1976; Keeling et al. , 1995]. However, there are periods during the atmospheric CO 2 record when this correlation does not hold and CO 2 levels are much lower than can be explained by the correlation with ENSO. These periods coincide with major volcanic eruptions. It has been well documented that a major eruption has a cooling effect on the surface and lower troposphere [ McCormick , 1992; Hansen, et al. , 1996]. Here we show that it is likely that this cooling has a significant and measurable effect on the carbon cycle. We use a coupled general circulation climate‐carbon cycle model to study the mechanisms involved. The model simulates the observed temperature and CO 2 response of the climate to the 1991 eruption of Mount Pinatubo. The surface cooling due to the eruption leads to reduced soil and plant respiration globally and increased gross primary productivity in the tropics. The result is significant uptake of carbon (1‐2 GtC yr −1 ) by the terrestrial biosphere for several years after the eruption. There is no significant variation in uptake or release of carbon by the oceans.