Micrometeorological measurements of methane flux at a boreal forest in central Alaska

• Main Authors: Ueyama,Masahito, Harazono,Yoshinobu, Okada,Ryo, Nojiri,Atsushi, Ohtaki,Eiji, Miyata,Akira
• Format: Report
• Language: English
• Published: International Arctic Research Center, University of Alaska/International Arctic Research Center, University of Alaska/Institution of Geosciences, University of Tsukuba/Graduate School of Natural Science and Technology, Okayama University/Graduate School of Natural Science and Technology, Okayama University/National Institute of Agro-Environmental Sciences 2006
• Subjects: boreal forest; methane flux; micrometeorological technique; central Alaska; Memoirs of National Institute of Polar Research; Polar Research; Alaska
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2516; http://id.nii.ac.jp/1291/00002516/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2516&item_no=1&attribute_id=18&file_no=1

Methane (CH_4) flux at a black spruce forest in central Alaska was determined by applying the three types of modified gradient method. One type used the eddy diffusivity obtained by CO_2 flux and CO_2 gradient. Others established the flux gradient relationship assuming Monin-Obukhov similarity. The wind speed and temperature profile functions were corrected for the influence of the roughness sublayer, and then applied to the modified gradient methods. More than 70% of the data were rejected by the strict quality control and a continental climate, such as calm wind. Although the diurnal variations of CH_4 flux by the three methods were different, the seasonal variation showed similar tendency; a weak emission on snowpack, an obvious emission around spring thaw, and CH_4 uptake in the late growing season. As calculated CH_4 flux was in the same range as with previous studies conducted by the chamber measurement.