Methane plume over south Asia during the monsoon season: satellite observation and model simulation X. Xiong1,2, S. Houweling3, J. Wei1,2, E. Maddy1,2, F. Sun1,2, and C. Barnet1 1NOAA/NESDIS/Center for Satellite Applications and Research, Camp Springs, Maryland, USA 2Perot Systems Government Services, Fairfax, Virginia, USA 3Netherlands Institute for Space Research, Utrecht, The Netherlands
Abstract. Satellite retrievals of methane (CH4) using the Atmospheric Infrared
Sounder (AIRS) on the EOS/Aqua platform from 2003–2007 show a strong,
plume-like enhancement of CH4 in the middle to upper troposphere over
South Asia during July, August and September, with the maximum occurring
in early September. Simulations using the global tracer model version 3
(TM3) also show similar seasonal enhancement of CH4 in the same region.
The model results also suggest that this enhancement is associated with
transport processes and local surface emissions, thus the observations of
tropospheric CH4 during the monsoon season may be used to constrain the
models for a better estimation of Asian CH4 sources. Further
comparisons between the AIRS retrievals and the model simulations suggest a
possible overestimate of emissions from rice paddies in Southeast Asia in
the scenario with the global emissions from rice of 60 Tg yr−1.
Moreover, the observed tropospheric CH4 enhancement from AIRS provides
evidence for the strong transport of atmospheric pollutants from the lower
to the upper troposphere in Asia during the monsoon season. The observed
rapid disappearance of the local CH4 maximum in September may provide
valuable information for studying the dissipation of the Tibetan anticyclone
and the withdrawal of monsoon.
Citation: Xiong, X., Houweling, S., Wei, J., Maddy, E., Sun, F., and Barnet, C.: Methane plume over south Asia during the monsoon season: satellite observation and model simulation, Atmos. Chem. Phys., 9, 783-794, doi:10.5194/acp-9-783-2009, 2009.