Forcing the Global Fire Emissions Database burned-area dataset into the CommunityLand Model version 5.0: impacts on carbon and water fluxes at high latitudes

Wildfires influence not only ecosystems but also carbonand water fluxes on Earth. Yet, the fire processes including the occurrence and consequences of fires are still limitedly represented in land surface models (LSMs). In particular, the performance of LSMs in estimatingburned areas across high northern latitudes is poor. In this study, weemployed the daily burned areas from the satellite-based Global Fire EmissionsDatabase (version 4) (GFED4) into the Community Land Model (version 5.0) with abiogeochemistry module (CLM5-BGC) to identify the effects of accurate firesimulation on carbon and water fluxes over Alaska and Eastern Siberia. Theresults showed that the simulated carbon emissions with burned areas fromGFED4 (i.e., experimental run) were significantly improved in comparison tothe default CLM5-BGC simulation, which resulted in opposite signs of the netecosystem exchange for 2004, 2005, and 2009 over Alaska between the defaultand experimental runs. Also, we identified that carbon emissions were moresensitive to the wildfires in Alaska than in Eastern Siberia, which could beexplained by the vegetation distribution (i.e., tree cover ratio). In termsof water fluxes, canopy transpiration in Eastern Siberia was relativelyinsensitive to the size of the burned area due to the interaction between leafarea and soil moisture. This study uses CLM5-BGC to improve ourunderstanding of the role of burned areas in ecohydrological processes athigh latitudes. Furthermore, we suggest that the improved approach will berequired for better predicting future carbon fluxes and climate change.

Automated summary

Wildfires have significant impacts on ecosystems and carbon-water fluxes on Earth. However, the representation of fire processes in land surface models is limited, especially in estimating burned areas in high northern latitudes. This study uses satellite data and model simulations to show that accurately simulating fires improves the estimation of carbon emissions and water fluxes in Alaska and Eastern Siberia. The study also finds that carbon emissions are more sensitive to wildfires in Alaska compared to Eastern Siberia, possibly due to differences in vegetation distribution. Additionally, water fluxes in Eastern Siberia are relatively insensitive to the size of the burned area due to the interaction between leaf area and soil moisture. This research improves our understanding of the role of burned areas in ecohydrological processes at high latitudes and highlights the need for improved approaches in predicting future carbon fluxes and climate change.