12:00 PM - 12:15 PM
[ACG35-06] Large decrease in CH4 emissions due to the Mount Pinatubo triggered atmospheric CH4 stabilization in the 1990s
Keywords:Atmospheric Methane, MIROC model simulations, VISIT terrestrial ecosystem model, Mount Pinatubo eruption
Both the model simulations show remarkable performance in reproducing the observations along with the year-to-year variability, in particular during the transient and constant period from 2000-2006. The model simulates more than 70% of the observed variability successfully over the southern and mid-latitudes (below 45oN). The Cao-scheme performs well in simulating the seasonal amplitude over the tropical sites (15oS-15oN), however, over the southern hemispheric sites (~ below 45oS), the WH-scheme performs better in simulating the amplitude compared to the emissions using the Cao scheme.
It was reported that a major difficulty in producing beginning of the reduction in CH4 growth rate could only be overcome by a decrease in CH4 emissions (Ghosh et al., 2015). Here we show the VISIT model simulated a decrease in CH4 emission by about 20 Tg/yr during June 1991 – May 1993, following the Mount Pinatubo eruption. Anomalous cooling over tropical (~20-25 oN) and extratropical (~60-65 oN) wetlands lead to more or less decrease in CH4 emission. Further, we investigate the sensitivity of CH4 concentrations to these emission perturbations during the pre- and post-Pinatubo eruption.