01 Nov 2022
01 Nov 2022
Status: this preprint is open for discussion.

Modeling global wildfire activity in the intermediate complexity University of Victoria Earth System Climate Model (UVic ESCM 2.9): the importance of the simulated climatology

Étienne Guertin and H. Damon Matthews Étienne Guertin and H. Damon Matthews
  • Department of Geography, Planning and Environment, Concordia University, Montréal, QC, Canada

Abstract. Fire is an integral part of the Earth system, interacting in complex ways with humans, vegetation and climate. Global fire activity is an important element of the carbon cycle, and understanding its role in the context of climate change is crucial. In order to represent the transient fire-climate-vegetation interactions and to integrate these in the long term climate projections of climate models, coupling these three components is necessary. Global fire models have been coupled to climate-vegetation models with complex atmosphere modules but these models are computationally intensive. In this research, we use the University of Victoria Earth System Climate Model (UVic ESCM), an ESCM of intermediate complexity to which we couple a process based global fire model, in order to develop a computationally efficient means of studying long term fire-climate-vegetation interactions. The fire model used simulates burned area based primarily on relative humidity, soil moisture and biomass density. The UViC ESCM’s simulated relative humidity is improved by parameterizing it according to the simulated precipitation, and observational variability is added to the simulated climatology to improve the variability of simulated burned area. The best parameterization achieves a moderate spatial agreement of simulated burned area with observational data. Tropical rainforests in South America and Africa, however, display very high burned fractions, due to the poorly simulated relative humidity input; indeed, when we used observed relative humidity to simulate fire activity, the pattern of burned area in the tropics improved substantially. This research demonstrates the importance of variability and regional patterns of climatology for global wildfire activity and the corresponding limitations of ESCMs that simplify atmospheric circulation. This suggests that using pattern scaling of climate variables as an input to fire models could provide such ESCMs of intermediate complexity with the ability to integrate global fire activity.

Étienne Guertin and H. Damon Matthews

Status: open (until 31 Dec 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • AC1: 'Comment on egusphere-2022-961', Étienne Guertin, 01 Nov 2022 reply

Étienne Guertin and H. Damon Matthews

Étienne Guertin and H. Damon Matthews


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Short summary
In this research project we add a wildfire model to a model that simulates global vegetation and climate. Our model is simpler and faster than most models. The model simulates wildfire with moderate accuracy but in some areas, the model is very far from reality. This shows that wildfires are highly influenced by climate and vegetation and that these need to be simulated with more accuracy to simulate wildfire. We suggest using a method that compromises between accuracy and speed of simulation.