A marginal modelling approach for predicting wildfire extremes across the contiguous United States

TL;DR

This paper introduces a spatial marginal modelling approach to predict wildfire extremes across the US, effectively handling missing data and outperforming benchmark methods in the 2021 data challenge.

Contribution

It proposes a novel spatial marginal modelling framework that leverages neighboring data and combines parametric and non-parametric techniques for wildfire prediction.

Findings

Significantly outperforms benchmark methods in predicting wildfire extremes.

Effectively models zero-inflated count data and burnt area distributions.

Provides a flexible framework for extending wildfire risk prediction models.

Abstract

This paper details a methodology proposed for the EVA 2021 conference data challenge. The aim of this challenge was to predict the number and size of wildfires over the contiguous US between 1993 and 2015, with more importance placed on extreme events. In the data set provided, over 14\% of both wildfire count and burnt area observations are missing; the objective of the data challenge was to estimate a range of marginal probabilities from the distribution functions of these missing observations. To enable this prediction, we make the assumption that the marginal distribution of a missing observation can be informed using non-missing data from neighbouring locations. In our method, we select spatial neighbourhoods for each missing observation and fit marginal models to non-missing observations in these regions. For the wildfire counts, we assume the compiled data sets follow a zero-inflated negative binomial distribution, while for burnt area values, we model the bulk and tail of each compiled data set using non-parametric and parametric techniques, respectively. Cross validation is used to select tuning parameters, and the resulting predictions are shown to significantly outperform the benchmark method proposed in the challenge outline. We conclude with a discussion of our modelling framework, and evaluate ways in which it could be extended.