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A multiyear estimate of methane fluxes in Alaska from CARVE atmospheric observations
Author(s) -
Miller Scot M.,
Miller Charles E.,
Commane Roisin,
Chang Rachel Y.W.,
Dinardo Steven J.,
Henderson John M.,
Karion Anna,
Lindaas Jakob,
Melton Joe R.,
Miller John B.,
Sweeney Colm,
Wofsy Steven C.,
Michalak Anna M.
Publication year - 2016
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2016gb005419
Subject(s) - environmental science , permafrost , flux (metallurgy) , arctic , methane , atmospheric sciences , tundra , climatology , greenhouse gas , atmospheric methane , climate model , climate change , geology , oceanography , ecology , materials science , biology , metallurgy
Methane (CH 4 ) fluxes from Alaska and other arctic regions may be sensitive to thawing permafrost and future climate change, but estimates of both current and future fluxes from the region are uncertain. This study estimates CH 4 fluxes across Alaska for 2012–2014 using aircraft observations from the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) and a geostatistical inverse model (GIM). We find that a simple flux model based on a daily soil temperature map and a static map of wetland extent reproduces the atmospheric CH 4 observations at the statewide, multiyear scale more effectively than global‐scale process‐based models. This result points to a simple and effective way of representing CH 4 fluxes across Alaska. It further suggests that process‐based models can improve their representation of key processes and that more complex processes included in these models cannot be evaluated given the information content of available atmospheric CH 4 observations. In addition, we find that CH 4 emissions from the North Slope of Alaska account for 24% of the total statewide flux of 1.74 ± 0.26 Tg CH 4 (for May–October). Global‐scale process models only attribute an average of 3% of the total flux to this region. This mismatch occurs for two reasons: process models likely underestimate wetland extent in regions without visible surface water, and these models prematurely shut down CH 4 fluxes at soil temperatures near 0°C. Lastly, we find that the seasonality of CH 4 fluxes varied during 2012–2014 but that total emissions did not differ significantly among years, despite substantial differences in soil temperature and precipitation.