B065-0011
Tropical forest CH4 and N2O: from chamber fluxes to tower concentration measurements
Friday, 11 December 2020
Poster
Hella van Asperen1, Thorsten Warneke1, Alessandro C De Araujo2, Bruce Forsberg3, Leonardo Ramos de Oliveira4, Thiago de Lima Xavier4, Marta Sá4, Paulo Teixeira4, Robson Azevedo de Oliveira4, Leila Leal5, Veber Moura4, Santiago Botia6, Jost V. Lavric7, Shujiro Komiya8, Arnoud Frumau9, Arjan Hensen9, Danielle van Dinther9, Pim van den Bulk9 and Justus Notholt1, (1)University of Bremen, Institute of Environmental Physics, Bremen, Germany, (2)Brazilian Agricultural Research Corporation (EMBRAPA), Belem, PA, Brazil, (3)National Institute of Amazonian Research, Manaus, Brazil, (4)Instituto Nacional de Pesquisas da Amazônia (INPA), Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), Manaus, Brazil, (5)Embrapa Amazônia Oriental, Belém, Brazil, (6)Max Planck Institute for Biogeochemistry, Biogeochemical Signals, Jena, Germany, (7)Max Planck Institute for Biogeochemistry, Biogeochemical Processes Department, Jena, Germany, (8)Max Planck Institute for Biogeochemistry, Biogeochemical Processes, Jena, Germany, (9)TNO, Utrecht, Netherlands
Abstract:
Methane (CH
4) is the second most important long-lived anthropogenic atmospheric greenhouse gas. Despite its importance, natural sources of methane, such as tropical wetlands, are still not well understood and a large source of uncertainty to the global CH
4 budget. The Amazonian rain forest is estimated to hold 90-120 Pg of carbon, which is approximately 14-27% of the carbon stored in vegetation worldwide. The region is characterized by high precipitation rates and large wetlands, and it has been estimated that the Amazon basin emits 7% of the annual total CH
4 emissions. Due to its remote location, micro-meteorological measurements are rare and usually absent for other gases than CO
2.
The 50 m high K34 tower (field site ZF2) is located in a pristine ‘Terre Firme’ tropical forest region 60 km northwest of Manaus (Brazil), and is located next to a waterlogged valley, a possible location for anaerobic CH4 production. In October 2018, in addition to the existing EC CO2 system, an in-situ FTIR-analyzer (measuring CO2, CO, CH4, N2O and δ13CO2) was set up to measure tower profile concentrations, above and below the canopy, continuously. By analyses of vertical and temporal nighttime concentrations patterns, an emission estimate for all gases could be made, and an ecosystem emission of ~1 nmol CH4 m-2 s-1 and ~0.5 nmol N2O m-2 s-1 was estimated. In addition, by use of different types of flux chambers, possible N2O and CH4 sources such as soils, trees, water and termite mounds were measured. By combining tower and flux chamber measurements, the role and magnitude of different ecosystem sources could be assessed. In this presentation, an overview of the measured CH4 and N2O forest concentrations and fluxes will be given.
