MOYA Aircraft Campaigns: Highlights from the Methane Observations and Yearly Assessment Project Aircraft Campaigns in Africa and the Arctic

The Methane Observations and Yearly Assessment (MOYA) project is tasked with better characterizing the global methane budget through a global measurement and modelling program. A specific target of the MOYA project was the assessment of tropical wetland fluxes as a potential explanation for an observed rising biogenic component of the global methane burden. To this end, four aircraft campaigns were conducted using the UK's Facility for Airborne Atmospheric Measurement (FAAM), based out of Senegal, Uganda, Zambia, and Sweden, between 2017 and 2019. This study presents highlights from those campaigns with a focus on observed methane hotspots sampled over wetlands (Zambia wet season and Arctic summer) and in biomass burning (Senegal and Uganda dry season). Novel flux methods for aircraft sampling, which use a vertical flux plane variant of Lagrangian mass balancing approach, have been used to calculate methane fluxes from Zambian swamps. VOC, NMHC and other trace gas measurements will also be discussed in the context of regional air quality and extensive biomass burning. We also describe the performance of an Aerodyne interband cascade laser spectrometer on the FAAM aircraft flown in 2017 for the first time, for continuous in-situ airborne measurements of methane, ethane and methane C-13 isotopologues. Together, these case studies inform modelling of regional and global fluxes of methane and highlight the importance of regional pollution and wide area wetland sources in tropical Africa.