The VEMAP integrated database for modelling United States ecosystem/vegetation sensitivity to climate change

For the Vegetation/Ecosystem Modelling and Analysis Project (VEMAP), we developed a model database of climate, soils and vegetation that was compatible with the requirements of three ecosystem physiology models and three vegetation life-form distribution models. A key constraint was temporal, spatial and physical consistency among data layers to provide these daily or monthly time step models with suitable common inputs for the purpose of model inter-comparison. The database is on a 0.5 latitude/longitude grid for the conterminous United States. The set as both daily and monthly representations of the same long-term climate. Daily temperature and precipitation were stochastically simulated with WGEN and daily solar radiation and humidity empirically estimated with CLIMSIM. We used orographically adjusted precipitation, surface temperature and surface windspeed monthly means to maintain consistency among these fields and with vegetation distribution. Vegetation classes were based on physiognomic and physiological properties that influence biogeochemical dynamics. Soils data include characteristics of the 1-4 dominant soils per cell to account for subgrid variability.