B043-01
First Amazon Methane budget based in atmospheric long term data provided by aircraft vertical profiles measurements

Wednesday, 9 December 2020: 19:00
Virtual
Luana S Basso1, Luciana V Gatti1, Luciano Marani1, Henrique L. G. Cassol Sr.2, Graciela Tejada1, Sergio Machado Correa3, John B Miller4, Manuel Gloor5, Lucas G. Domingues1,6, Egidio Arai7, Alber Sánchez2, Luiz EOC Aragão8, Caio Silvestre de Carvalho Correia1,9, Raiane A. L. Neves1 and Stephane P. Crispim1, (1)INPE National Institute for Space Research, CCST, Sao Jose dos Campos, Brazil, (2)INPE National Institute for Space Research, Sao Jose dos Campos, Brazil, (3)UERJ Rio de Janeiro State University, Resende, Brazil, (4)NOAA, Global Monitoring Laboratory, Boulder, CO, United States, (5)University of Leeds, School of Geography, Leeds, United Kingdom, (6)GNS Science, Lower Hutt, New Zealand, (7)INPE National Institute for Space Research, OBT, Sao Jose dos Campos, Brazil, (8)INPE National Institute for Space Research, Remote Sensing Division, Sao Jose dos Campos, Brazil, (9)IPEN Nuclear Energy Research Institute, Sao Paulo, Brazil
Recorded Presentation
Abstract:
The overall Methane (CH4) budget remains highly uncertain even with the efforts to improve the estimates and contributions of its many sources (natural and anthropogenic) and few sinks. Wetland emissions are considered the primary natural CH4 source but with large uncertainty in estimations. Tropical regions like the Amazon, host some of the largest wetlands areas on the globe. However, these regions are still poorly observed with large-scale integrating observations. Here we present the first long term (2010-2018) atmospheric sampling of the lower troposphere over the Amazon using regular vertical profile (300m to 4.4km height) observations of CH4 and carbon monoxide (CO) at four sites. The sampling was nearly biweekly using small aircrafts, to provide solid seasonal and annual CH4 budgets with large spatial resolution. Was calculated a CO/CH4 ratio to estimate CH4 emissions from biomass burning. An increase in emissions mainly during the dry season at all sites from biomass burning was observed. The results show a regional variation in biogenic CH4 emissions (total minus biomass burning emissions). There are comparably high emissions from the Amazon northeast region (SAN) exhibiting strong seasonality, with particularly high CH4 fluxes one month before (February/March) the wet season peak. The second period of high emissions occurs during the beginning of the dry season (August). In the other three sites (ALF, RBA and TAB_TEF) located further downwind along the main air-stream, it were observed lower emissions, which represents approximately 20-33 % of what was observed in the northeast region and with a clear annual seasonality. Besides, we discuss how these data vary throughout the years and how it can be correlated to climate variables (temperature, precipitation and equivalent water thickness) and with human-driven influence (biomass burning), which both could be impacting this variability and annual seasonality.
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