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Investigating Methane Trend and Variability using the GFDL-AM4

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Wednesday, 14 November 2018, 12:00

Wednesday, November 14, 2018. 12:00PM. Investigating Methane Trend and Variability using the GFDL-AM4. Jian He, NOAA GFDL. Sponsored by NOAA GFDL. More information here.

Changes in atmospheric methane abundance have implications for both chemistry and climate as methane is both a strong greenhouse gas and an important precursor for tropospheric ozone. A better understanding of the drivers of trends and variability in methane abundance over the recent past is therefore critical for building confidence in predictions of future methane levels. In this work, the representation of methane is improved in AM4 and the total methane emissions are optimized for the period of 1980-2014. The AM4 simulation with optimized methane emissions is able to reproduce the observed spatio-temporal variability in surface and column-averaged methane as well as vertical profiles. We also include methane source tagged tracers and a representation of methane isotope in the model to explore the role of individual sources and sinks in driving methane variability. The preliminary results indicate the methane stabilization during 1999-2006 is mainly due to the balance between increasing methane emissions and sinks while the renewed methane growth after 2006 is most likely due to the increased methane emissions (especially from energy sector) outweighing the methane sinks.

Location  NOAA GFDL, Smagorinsky Seminar Room, Princeton University, Princeton, NJ.