Final published version, 2.22 MB, PDF document
Available under license: CC BY
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Effects of climate-induced changes in isoprene emissions after the eruption of Mount Pinatubo
AU - Telford, P. J.
AU - Lathiere, Juliette
AU - Abraham, N. L.
AU - Archibald, A. T.
AU - Braesicke, P.
AU - Johnson, C. E.
AU - Morgenstern, O.
AU - O'Connor, F. M.
AU - Pike, R. C.
AU - Wild, O.
AU - Young, Paul
AU - Beerling, D. J.
AU - Hewitt, C. N.
AU - Pyle, J.
PY - 2010/8/3
Y1 - 2010/8/3
N2 - In the 1990s the rates of increase of greenhouse gas concentrations, most notably of methane, were observed to change, for reasons that have yet to be fully determined. This period included the eruption of Mt. Pinatubo and an El Nino warm event, both of which affect biogeochemical processes, by changes in temperature, precipitation and radiation. We examine the impact of these changes in climate on global isoprene emissions and the effect these climate dependent emissions have on the hydroxy radical, OH, the dominant sink for methane. We model a reduction of isoprene emissions in the early 1990s, with a maximum decrease of 40 Tg(C)/yr in late 1992 and early 1993, a change of 9%. This reduction is caused by the cooler, drier conditions following the eruption of Mt. Pinatubo. Isoprene emissions are reduced both directly, by changes in temperature and a soil moisture dependent suppression factor, and indirectly, through reductions in the total biomass. The reduction in isoprene emissions causes increases of tropospheric OH which lead to an increased sink for methane of up to 5 Tg(CH4)/year, comparable to estimated source changes over the time period studied. There remain many uncertainties in the emission and oxidation of isoprene which may affect the exact size of this effect, but its magnitude is large enough that it should remain important.
AB - In the 1990s the rates of increase of greenhouse gas concentrations, most notably of methane, were observed to change, for reasons that have yet to be fully determined. This period included the eruption of Mt. Pinatubo and an El Nino warm event, both of which affect biogeochemical processes, by changes in temperature, precipitation and radiation. We examine the impact of these changes in climate on global isoprene emissions and the effect these climate dependent emissions have on the hydroxy radical, OH, the dominant sink for methane. We model a reduction of isoprene emissions in the early 1990s, with a maximum decrease of 40 Tg(C)/yr in late 1992 and early 1993, a change of 9%. This reduction is caused by the cooler, drier conditions following the eruption of Mt. Pinatubo. Isoprene emissions are reduced both directly, by changes in temperature and a soil moisture dependent suppression factor, and indirectly, through reductions in the total biomass. The reduction in isoprene emissions causes increases of tropospheric OH which lead to an increased sink for methane of up to 5 Tg(CH4)/year, comparable to estimated source changes over the time period studied. There remain many uncertainties in the emission and oxidation of isoprene which may affect the exact size of this effect, but its magnitude is large enough that it should remain important.
KW - TRACE GAS BUDGETS
KW - ATMOSPHERIC METHANE
KW - METHYL CHLOROFORM
KW - GROWTH-RATE
KW - MODEL
KW - VARIABILITY
KW - OZONE
KW - CHEMISTRY
KW - TROPOSPHERE
KW - TRANSPORT
U2 - 10.5194/acp-10-7117-2010
DO - 10.5194/acp-10-7117-2010
M3 - Journal article
VL - 10
SP - 7117
EP - 7125
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
SN - 1680-7316
IS - 15
ER -