The importance of antecedent vegetation and drought conditions as global drivers of burnt areas
File(s)
Published version
Author(s)
Kuhn- Regnier, Alexander
Voulgarakis, Apostolos
Nowack, Peter
Forkel, Matthias
Prentice, Iain Colin
Type
Journal Article
Abstract
The seasonal and longer-term dynamics of fuel accumulation affect fire seasonality and the occurrence of extreme wildfires. Failure to account for their influence may help to explain why state-of-the-art fire models do not simulate the length and timing of the fire season or interannual variability in burnt area well. We investigated the impact of accounting for different timescales of fuel production and accumulation on burnt area using a suite of random forest regression models that included the immediate impact of climate, vegetation, and human influences in a given month and tested the impact of various combinations of antecedent conditions in four productivity-related vegetation indices and in antecedent moisture conditions. Analyses were conducted for the period from 2010 to 2015 inclusive. Inclusion of antecedent vegetation conditions representing fuel build-up led to an improvement of the global, climatological out-of-sample R2 from 0.579 to 0.701, but the inclusion of antecedent vegetation conditions on timescales ≥ 1 year had no impact on simulated burnt area. Current moisture levels were the dominant influence on fuel drying. Additionally, antecedent moisture levels were important for fuel build-up. The models also enabled the visualisation of interactions between variables, such as the importance of antecedent productivity coupled with instantaneous drying. The length of the period which needs to be considered varies across biomes; fuel-limited regions are sensitive to antecedent conditions that determine fuel build-up over longer time periods (∼ 4 months), while moisture-limited regions are more sensitive to current conditions that regulate fuel drying.
Date Issued
2021-06-29
Date Acceptance
2021-05-18
Citation
Biogeosciences, 2021, 18, pp.3861-3879
ISSN
1726-4170
Publisher
Copernicus Publications
Start Page
3861
End Page
3879
Journal / Book Title
Biogeosciences
Volume
18
Copyright Statement
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/)
the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/)
License URL
Sponsor
Natural Environment Research Council [2006-2012]
European Research Council
Commission of the European Communities
Leverhulme Trust
The Leverhulme Trust
Grant Number
NE/P012345/1
787203
787203
RC-2018-023
Subjects
04 Earth Sciences
05 Environmental Sciences
06 Biological Sciences
Meteorology & Atmospheric Sciences
Publication Status
Published