Comment on gmd-2022-294

Abstract

Wildfires influence not only ecosystems but also carbon and water fluxes on Earth. Yet, the fire processes are still limitedly represented in land surface models (LSMs), thus simulating the occurrence and consequences of fires. Especially, the performance of LSMs in estimating burned areas across high northern latitudes is poor. In this study, we employed the daily burned areas from the satellite-based global fire emission database (version 4) (GFED4) into the community land model (version 5.0) with a biogeochemistry module (CLM5-BGC) to identify the effects of accurate fire simulation on carbon and water fluxes over Alaska and Eastern Siberia. The results showed that the simulated carbon emissions with the burned areas from GFED4 (i.e., experimental run) were significantly improved in comparison to the open-loop run (i.e., default run), which resulted in opposite trends of the net ecosystem exchange for 2004, 2005, and 2009 over Alaska between the open-loop and experimental runs. Also, we identified carbon emissions were more sensitive to the wildfires in Alaska than in Eastern Siberia, which could be explained by the vegetation distribution (i.e., tree cover ratio). In terms of water fluxes, canopy transpiration in Eastern Siberia was relatively insensitive to the size of burned area due to the interaction between leaf size and soil moisture. This study uses CLM5-BGC to improve our understanding of the role of burned areas in eco-hydrological processes at high latitudes. Furthermore, we suggest that the improved approach will be required for better predicting future carbon fluxes and climate change.