Simulating winds and floods-regional weather-river prediction and regional climate research

The authors at the University of California Lawrence Livermore National Laboratory (UC-LLNL) developed a coupled modeling system. The system simulates regional-scale weather, land-surface processes, and river flow using large-scale atmospheric data and land surface terrain information as input. This Coupled Atmosphere River Flow Simulation (CARS) system consists of the mesoscale atmospheric simulation (MAS) model coupled with a soil-plant-snow (SPS) model, our Automated Land Analysis System (ALAS) and a physically-based fully distributed surface hydrology and river flow model, TOPMODEL. The MAS model is a primitive-equation, limited-area model. It includes a third order accurate advection scheme and physical processes for: (1) precipitation and thermal forcing due to deep convective clouds and stratiform clouds; (2) solar and terrestrial radiative transfer within the atmosphere, and (3) turbulent transfer at the Earth's surface and within the atmosphere. Interactions between the atmosphere and land-surface are computed using the SPS model. It is interactively coupled to the MAS. The SPS keeps track of hydrologic variables such as water stored in the snowpack that is crucial for assessing the available water resources. The ALAS provides topographic properties, such as river networks and watershed areas, at specified resolutions, using digital elevation model data.