Integrating Agricultural Practices into the TRIPLEX-GHG Model v2.0 for Simulating Global Cropland Nitrous Oxide Emissions: Model Development and Evaluation

Abstract. Nitrous oxide (N2O) emissions from croplands are one of the most important greenhouse gas sources, and it is difficult to simulate on a large scale. In order to simulate N2O emissions from global croplands, a new version of the process-based TRIPLEX-GHG model was developed by coupling the major agricultural activities. The coefficient of the NO3− consumption rate for denitrification (COEdNO3) was found to be the most sensitive parameter based on sensitivity analysis, and it was calibrated using field data from 39 observation sites across major croplands globally. The model performed well when simulating the magnitude of the daily N2O emissions and was able to capture the temporal patterns of the N2O emissions. The COEdNO3 ranged from 0.01 to 0.05, and the continental mean of the parameter was used for the model validation. The validation results indicate that the means of the measured daily N2O fluxes during the experiment periods are highly correlated with the modeled results (R2 = 0.87). Consequently, our model simulation results demonstrate that the new version of the TRIPLEX-GHG model can reliably simulate N2O emissions from various croplands at the global scale.