Satellite-derived methane hotspot emission estimates using a fast data-driven method
Michael Buchwitz1, Oliver Schneising1, Maximilian Reuter1, Jens Heymann1, Sven Krautwurst1, Heinrich Bovensmann1, John P. Burrows1, Hartmut Boesch2,3, Robert J. Parker2,3, Rob G. Detmers4, Otto P. Hasekamp4, Ilse Aben4, André Butz5, and Christian Frankenberg6,71Institute of Environmental Physics (IUP), University of Bremen, Bremen, Germany 2Earth Observation Science, University of Leicester, Leicester, UK 3NERC National Centre for Earth Observation, Leicester, UK 4SRON Netherlands Institute for Space Research, Utrecht, the Netherlands 5Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany 6Division of Geological and Planetary Sciences, California Institute of Technology, California, Pasadena, CA, USA 7Jet Propulsion Laboratory, Pasadena, CA, USA
Received: 22 Aug 2016 – Accepted for review: 23 Aug 2016 – Discussion started: 24 Aug 2016
Abstract. Methane is an important atmospheric greenhouse gas and an adequate understanding of its emission sources is needed for climate change assessments, predictions and the development and verification of emission mitigation strategies. Satellite retrievals of near-surface-sensitive column-averaged dry-air mole fractions of atmospheric methane, i.e., XCH4, can be used to quantify methane emissions. Here we present a simple and fast method to estimate emissions of methane hotspots from satellite-derived XCH4 maps. We apply this method to an ensemble of XCH4 data products consisting of two products from SCIAMACHY/ENVISAT and two products from TANSO-FTS/GOSAT covering the time period 2003–2014. We obtain annual emissions of the source areas Four Corners in the southwestern USA, for the southern part of Central Valley, California, and for Azerbaijan and Turkmenistan. We find that our estimated emissions are in good agreement with independently derived estimates for Four Corners and Azerbaijan. For the Central Valley and Turkmenistan our estimated annual emissions are higher compared to the EDGAR v4.2 anthropogenic emission inventory. For Turkmenistan we find on average about 50 % higher emissions with our annual emission uncertainty estimates overlapping with the EDGAR emissions. For the region around Bakersfield in the Central Valley we find a factor of 6–9 higher emissions compared to EDGAR albeit with large uncertainty. Major methane emission sources in this region are oil/gas and livestock. Our findings corroborate recently published studies based on aircraft and satellite measurements and new bottom-up estimates reporting significantly underestimated methane emissions of oil/gas and/or livestock in this area in inventories.
Buchwitz, M., Schneising, O., Reuter, M., Heymann, J., Krautwurst, S., Bovensmann, H., Burrows, J. P., Boesch, H., Parker, R. J., Detmers, R. G., Hasekamp, O. P., Aben, I., Butz, A., and Frankenberg, C.: Satellite-derived methane hotspot emission estimates using a fast data-driven method, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-755, in review, 2016.