Performance of CH4MOD wetland for the case study of different regions of natural Chinese wetland

Reliable national estimates of CH₄ emissions from natural wetlands depend on model validation based on site observations. We therefore evaluated the performance of the CH4MOD_wetland model in simulating CH₄ emissions from 11 representative wetland sites in five regions of China. Model performance analysis showed that this method effectively simulates differences in the CH₄ fluxes between different sites and regions. The model efficiency for estimating the daily CH₄ fluxes in the northeastern China (NE), Inner Mongolia and northwestern China (NW), the North China plain and the Middle-Lower Yangtze Plain (E) and the Qinghai Tibetan Plateau (SW) was 0.51, 0.20, 0.52 and 0.65, respectively. The efficiency for estimating the annual mean CH₄ fluxes in southern China (S) was 0.99. Systematic negative deviation between the simulated and observed CH₄ emissions existed in all regions, especially in the NW region, which had a mean deviation (RMD) value of − 36.7%. On the national scale, the root mean square error (RMSE), the RMD, the model efficiency (EF) between the simulated and observed seasonal values were 28.7%, − 7.8% and 0.93, respectively. The CH₄ emissions showed the highest sensitivity to air temperature in the NE and SW regions, and to water table depth in the E region. Based on the sensitivity analysis, future climate warming and wetting are likely to increase the wetland CH₄ emissions at different levels in all regions of China.