Estimation of CLM5.0 Parameters for Improving Grassland Productivity Simulation in Hulunburi, Inner Mongolia

Due to global warming and overgrazing, grassland degradation and alkaline problems are becoming more and more serious [1]. Monitoring grassland growth dynamically is helpful to take protective measures in time. Grassland productivity is a quantitative evaluation index for representing grassland growth. CLM5.0 (Community Land Model 5.0) can realize spatial-temporal continuous grassland productivity simulation, the most promising land surface process model ^[2] . Compared with previous versions, CLM5.0 has improved soil evaporation, vegetation canopy interception, and so on ^[3] , which makes the simulation closer to reality, but also increases the complexity of the model. The parameters must be optimized when the model is applied to the target region.In this study, the parameters of CLM5.0 for the simulation of grassland productivity in Hulunbuir were optimized. Firstly, parameter sensitivity analysis was carried out. Secondly, parameter optimization was carried out for sensitive parameters using DREAM (Differential Evolution Adaptive Metropolis), and grouping experiments were conducted for key phenological parameters. Finally, precision analysis was carried out for optimization results.