Cloud-to-ground lightning and near-surface fire weather control wildfire
occurrence in Arctic tundra
Jiaying He1,2, Tatiana V. Loboda2,
Dong Chen2, and Nancy H. F. French3
1Department of Earth System Science, Ministry of
Education Key Laboratory for Earth System Modeling, Institute for Global
Change Studies,Tsinghua University, Beijing 100084, China.2Department of Geographical Sciences, University of
Maryland, College Park, MD 20742, US.
3Michigan Technological Research Institute, Michigan
Technological University, Ann Arbor, MI 48105, US.
Corresponding author: Jiaying He
(hejiaying0608@gmail.com)
Key Points:
- Cloud-to-ground lightning probability is the key driver of fire
occurrence in Arctic tundra.
- Warmer and drier near-surface fire weather conditions also support
tundra burnings.
- Empirical-dynamic framework combining WRF and statistical learning
methods shows strong capability for modeling of tundra fire
occurrence.
Abstract
Wildfire is common across the pan-Arctic tundra. Tundra fires exert
significant impacts on terrestrial carbon balance and ecosystem
functioning. Interactions between fire and climate change can enhance
their impacts on the Arctic. However, the driving mechanisms of tundra
fire occurrences remain poorly understood. This study focuses on
identifying key environmental factors controlling fire occurrence in
Arctic tundra of Alaska. Our random forest models, considering ignition
source, fuel, fire weather, and topography, have shown a strong
predictive capability with an overall accuracy above 91%. We found
cloud-to-ground (CG) lightning probability by far the dominant driver
controlling tundra fire occurrence. Warmer and drier near-surface
weather was required to support burning, while fuel composition and
topography have modest impacts on fire occurrence. Our results highlight
the critical role of CG lightning in driving tundra fires and that
incorporating lightning modeling is essential for fire monitoring,
forecasting, and management in the Arctic.