Regional Climatic Effects of Crop Growth Modeled by the Coupled CWRF-CROP System

Many studies have been done on the crop responses to climate change and variability using off-line crop growth models. However the activities of crop growth impose significant influences on weather and climate on global, regional, and local scales by changing the physical characteristics of the land surface and modulating the atmospheric greenhouse gas concentrations. Therefore it is essential to study the climate-crop interactions using fully coupled climate-crop models. In this study, the cotton growth model, GOSSYM (an acronym from the word Gossypium, the genus of cotton), re-engineered in software with improved physical processes was coupled with the state-of-the-art Climate extension of the Weather and Research Forecasting model (CWRF). We used the fully coupled CWRF-CROP modeling system to investigate the comprehensive feedbacks to local and regional climate from the seasonal changes in land cover characteristics caused by crop growth, including roughness and displacement, surface albedo, root depth and density, photosynthesis, and irrigation. The preliminary results showed that crop growth greatly alters the radiaitive forcing, near surface aerodynamic processes, and surface and sub-surface hydrology, which affects local and regional climate.