Micrometeorological measurements of CH₄ and CO₂ exchange between the atmosphere and subarctic tundra

Abstract

Exchanges of methane and carbon dioxide between the atmosphere and the Arctic tundra were measured continuously near Bethel, Alaska (61ø05.41'N, 162ø00.92'W), for 5 weeks during July and August 1988. Fluxes were obtained directly using eddy correlation at 12-m altitude, and concentrations were measured sequentially at eight altitudes between 0 and 12 m. A prototype differential infrared absorption methane instrument based on a Zeeman-split HeNe laser was used for determination of methane and a flame ionization detector for total hydrocarbons (TI-IC). Methane was found to account for nearly all the THC concentrations and fluxes. Methane fluxes at the tower site were apportioned to various methane-producing habitats, using a satellite image to classify surface vegetation at 20 x 20 m resolution. The "footprint" of the tower was computed using a Gaussian plume model for dispersion in the surface layer. . About 6% of the seasonal net uptake was returned to the atmosphere as methane.

Large tundra methane burst during onset of freezing

“…The scale and dynamics of growing-season methane emissions from tundra settings have been documented mostly through flux measurements made with low time resolution using manual chambers 5,6,10 together with some at higher time resolution taken only during the growing season 7,11,12 . Here we report a data set that extends hourly CH 4 flux measurements from a high Arctic setting into the frozen season.…”

Estimating regional-scale methane flux and budgets using CARVE aircraft measurements over Alaska

“…Fan et al, 1992;Sturtevant et al, 2012;Zona et al, 2016), providing insight into factors controlling CH 4 emissions at the scale of ∼ 1 m to ∼ 1 km. These studies have revealed that CH 4 emissions are spatially inhomogeneous at those scales and are highly dependent on local conditions such as soil moisture, temperature, elevation, and soil carbon.…”

Determination of Gas Exchange on the Border Between Ecosystem and Atmosphere: Inverse Modeling

“…мере определяющая измеренную величину общего потока, например, 90% этого потока ("…footprint, i. e., the area contributing by percentage, e. g., 90% of the total flux"). Подробное рассмотрение теории футпринта и конкретные модели для него см., например, в [36][37][38][39][40][41], причем в работе [36] даны ссылки еще на 22 конкретные модели футпринта.…”