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- Title
Daily burned area and carbon emissions from boreal fires in Alaska.
- Authors
Veraverbeke, S.; Rogers, B. M.; Randerson, J. T.
- Abstract
Boreal fires burn carbon-rich organic soils, thereby releasing large quantities of trace gases and aerosols that influence atmospheric composition and climate. To better understand the factors regulating boreal fire emissions, we developed a statistical model of carbon consumption by fire for Alaska with a spatial resolution of 500 m and a temporal resolution of one day. We used the model to estimate variability in carbon emissions between 2001 and 2012. Daily burned area was mapped using imagery from the Moderate Resolution Imaging Spectroradiometer combined with perimeters from the Alaska Large Fire Database. Carbon consumption was calibrated using available field measurements from black spruce forests in Alaska. We built two nonlinear multiplicative models to separately predict above- and belowground carbon consumption by fire in response to environmental variables including elevation, day of burning within the fire season, pre-fire tree cover and the differenced normalized burn ratio (dNBR). Higher belowground consumption occurred later in the season and for mid-elevation regions. Aboveground and belowground consumption also increased as a function of tree cover and the dNBR, suggesting a causal link between the processes regulating these two components of consumption. Between 2001 and 2012, the median fuel consumption was 2.48 kgCm-2 and the median pixel-based uncertainty (SD of prediction error) was 0.38kgCm . There were considerable amounts of burning in other cover types than black spruce and consumption in pure black spruce stands was generally higher. Fuel consumption originated primarily from the belowground fraction (median = 2.30kgCm-2 for all cover types and 2.63kgCm-2 for pure black spruce stands). Total carbon emissions varied considerably from year to year, with the highest emissions occurring during 2004 (67TgC), 2005 (44TgC), 2009 (25TgC), and 2002 (16TgC) and a mean of 14TgC per year between 2001 and 2012. Our analysis highlights the importance of accounting for the spatial heterogeneity within fuels and consumption when extrapolating emissions in space and time. This data on daily burned area and emissions may be useful for in understanding controls and limits on fire growth, and predicting potential feedbacks of changing fire regimes.
- Subjects
HISTOSOLS; ATMOSPHERIC carbon dioxide; TAIGA ecology; CLIMATE change; AEROSOLS
- Publication
Biogeosciences Discussions, 2014, Vol 11, Issue 12, p17579
- ISSN
1810-6277
- Publication type
Article
- DOI
10.5194/bgd-11-17579-2014