The regional effects of CO2 and landscape change using a coupled plant andmeteorological model

A meteorological model, the Regional Atmospheric Modelling System (RAMS), a nd a plant model, the General Energy and Mass Transfer Model (GEMTM), are c oupled in this study. The integrated modelling system was used to investiga te regional weather conditions in the central grasslands of the USA for thr ee experimental scenarios: land cover is changed from current to potential vegetation; radiative forcing is changed from 1 X CO2 to 2 X CO2; and biological CO2 partial pressures are doubled. Results indicate that the biological effect of enriched CO2, and of land-us e change exhibit dominant effects on regional meteorological and biological fields, which were observed for daily to seasonal time scales and grid to regional spatial scales. Simulated radiation impacts of 2 X CO2 were minima l, with interactive effects between the three experimental scenarios as lar ge as the radiational impact alone. Model results highlight the importance of including 2 X CO2 biological effects when simulating possible future cha nges in regional weather.