author = "Webb, Alex J. and Bosch, Hartmut and Parker, Robert J. and Gatti, 
                         Luciana Vanni and Gloor, Emanuel and Palmer, Paul I. and Basso, 
                         Luana S. and Chipperfield, Martyn P. and Correia, Caio S. C. and 
                         Domingues, Lucas G. and Feng, Liang and Gonzi, Siegfried and 
                         Miller, John B. and Warneke, Thorsten and Wilson, Christopher",
          affiliation = "{University of Leicester} and {University of Leicester} and 
                         {University of Leicester} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {University of Leeds} and {University of 
                         Edinburgh} and {Instituto de Pesquisas Energ{\'e}ticas e 
                         Nucleares (IPEN)} and {University of Leeds} and {Instituto de 
                         Pesquisas Energ{\'e}ticas e Nucleares (IPEN)} and {Instituto de 
                         Pesquisas Energ{\'e}ticas e Nucleares (IPEN)} and {University of 
                         Edinburgh} and {University of Edinburgh} and {National Oceanic and 
                         Atmospheric Administration (NOAA)} and {University of Bremen} and 
                         {University of Leeds}",
                title = "CH4 concentrations over the Amazon from GOSAT consistent with in 
                         situ vertical profile data",
              journal = "Journal of Geophysical Research: Atmospheres",
                 year = "2016",
               volume = "121",
               number = "18",
                pages = "11006--11020",
                month = "Sept.",
             keywords = "GOSAT, amazon, methane, wetlands, aircraft, CH4.",
             abstract = "The Amazon Basin contains large wetland ecosystems which are 
                         important sources of methane (CH4). Spaceborne observations of 
                         atmospheric CH4 can provide constraints on emissions from these 
                         remote ecosystems, but lack of validation precludes robust 
                         estimates. We present the first validation of CH4 columns in the 
                         Amazon from the Greenhouse gases Observing SATellite (GOSAT) using 
                         aircraft measurements of CH4 over five sites across the Amazon 
                         Basin. These aircraft profiles, combined with stratospheric 
                         results from the TOMCAT chemical transport model, are vertically 
                         integrated allowing direct comparison to the GOSAT XCH4 
                         measurements (the column-averaged dry air mole fraction of CH4). 
                         The measurements agree within uncertainties or show no significant 
                         difference at three of the aircraft sites, with differences 
                         ranging from -1.9ppb to 6.6ppb, while at two sites GOSAT XCH4 is 
                         shown to be slightly higher than aircraft measurements, by 8.1ppb 
                         and 9.7ppb. The seasonality in XCH4 seen by the aircraft profiles 
                         is also well captured (correlation coefficients from 0.61 to 
                         0.90). GOSAT observes elevated concentrations in the northwest 
                         corner of South America in the dry season and enhanced 
                         concentrations elsewhere in the Amazon Basin in the wet season, 
                         with the strongest seasonal differences coinciding with regions in 
                         Bolivia known to contain large wetlands. Our results are 
                         encouraging evidence that these GOSAT CH4 columns are generally in 
                         good agreement with in situ measurements, and understanding the 
                         magnitude of any remaining biases between the two will allow more 
                         confidence in the application of XCH4 to constrain Amazonian CH4 
                  doi = "10.1002/2016JD025263",
                  url = "http://dx.doi.org/10.1002/2016JD025263",
                 issn = "2169-8996 and 2169-897X",
             language = "en",
           targetfile = "Webb_ch4.pdf",
        urlaccessdate = "29 nov. 2020"