Quantify the Effect of Historical Fire Disturbance on Terrestrial Carbon Balance using a Global Vegetation Model with an Improved Prognostic Fire Module

Globally, fire disturbance represents a significant source of perturbation for terrestrial carbon cycle by releasing an annual 2~4 Pg carbon into atmosphere. Yet the effect of fire disturbance on the terrestrial carbon balance might be regionally different, depending on the type of vegetations that are burned, and the difference in fire regime. In Savanna vegetation where fires burn more frequently, it's assumed that carbon released into atmosphere could be reabsorbed by ecosystems within few years; whereas in boreal forest, carbon released in fire can only be recovered by an extended long time of carbon sink lasting for decades. With multiple methods including satellite observation, ground experiment, and vegetation modeling, our understanding of the role of fire in terrestrial carbon cycle has been greatly advanced in the past decade. Despite this, we noticed that studies quantifying fire emissions seldom reported carbon balance simultaneously, whereas studies aimed at quantifying regional or global carbon balance rarely included fire emissions as an explicit component of carbon balance analysis. In this study, we implemented a more realistic and complex fire module (SPITFIRE) into a process-based global vegetation model (ORCHIDEE). And we did simulations for historical fire disturbance to evaluate the model performance by comparing simulation results with satellite observations and other published fire emission estimations. Then the model has been used to quantify the effect of historical fire disturbance on terrestrial carbon balance for the 20th century. The results show that the contribution of fire to the terrestrial carbon balance is highly variant among different regions and vegetation types.