Airborne measurements of atmospheric methane

Methane signal over a lake.
Graphic: Jörg Hartmann (AWI)
Methane signal over a lake. (Graphic: J. Hartmann, AWI)

Methane (CH4) is an important greenhouse gas. Though its concentration in the atmosphere is lower than that of carbon dioxide, its efficiency (per molecule) as a greenhouse gas is significantly larger (IPPC, 2007). Considerable sources for methane is thawing in permafrost regions, e.g. in Sibiria.

CH4 introduces a significant feedback mechanism to the climate change problem, as global warming leads to a poleward retreat of vast permafrost regions in the northern hemisphere. This increases the total area of active sources of CH4 emission into the atmosphere.

Estimations of the CH4 emissions from northern swamps vary strongly due to (1) the extensive variability of the CH4 emission between and within different swamp areas, (2) the very limited knowledge of these fluxes for various types of soils, and (3) the lack of representative data for vast areas like the enormous swamps, e.g. in Sibiria.

Recent advances in sensor development now permit to directly measure turbulent CH4 fluxes from natural emitting surfaces. Thus, in addition to the turbulence sensors a fast methane sensor can be installed in the research aircraft Polar 5.

A test experiment to observe CH4-fluxes with this equipment as been carried out during a collaborative campaign in June 2011, together with GFZ-Potsdam and the University of Bremen.