Modeling the volcanic signal in the atmospheric CO2 record

Authors
Citation
Cd. Jones et Pm. Cox, Modeling the volcanic signal in the atmospheric CO2 record, GLOBAL BIOG, 15(2), 2001, pp. 453-465
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GLOBAL BIOGEOCHEMICAL CYCLES
ISSN journal
0886-6236 → ACNP
Volume
15
Issue
2
Year of publication
2001
Pages
453 - 465
Database
ISI
SICI code
0886-6236(200106)15:2<453:MTVSIT>2.0.ZU;2-3
Abstract
There is significant intel annual variability in the atmospheric concentrat ion of carbon dioxide even when the effect of anthropogenic sources has bee n accounted for. It has been shown that this variability is correlated with the El Nine Southern Oscillation (ENSO) cycle [Bacastow, 1976; Keeling et al., 1995]. However, ther e are periods during the atmospheric CO2 record w hen this correlation does not hold and CO2 levels ar e much lower than can be explained by the cor relation with ENSO. These periods coincide with maj or volcanic eruptions. It has been well documented that a major eruption ha s a cooling effect on the surface and lower troposphere [McCormick, 1992; H ansen et al., 1996]. Her e we show that it is likely that this cooling has a significant and measurable effect on the carbon cycle. We use a coupled g eneral circulation climate-carbon cycle model to study the mechanisms invol ved. The model simulates the observed temperature and CO2 response of the c limate to the 1991 eruption of Mount Pinatubo. The surface cooling due to t he eruption leads to reduced soil and plant respiration globally and increa sed gross primary productivity in the tropics. The result is significant up take of carbon (1-2 GtC yr(-1)) by the terrestrial biosphere for several ye ars after the eruption. There is no significant variation in uptake or rele ase of carbon by the oceans.