The versatile integrator of surface and atmosphere processes part 1. Model description

This paper describes an integration of recent new developments in snow, runoff and vegetation growth into the National Center for Atmospheric Research Land Surface Model (NCAR LSM). The new model, referred to as the Versatile Integrator of Surface and Atmosphere processes (VISA), has been validated with observed data. The results have demonstrated that the NCAR LSM, after integrating with these new developments, produces improved simulations of snow and runoff over the baseline version, and has an added capability to simulate the dynamics of leaf area index (LAI). Moreover, VISA, through its integration of new schemes, is not only important for studying land-atmosphere interactions in its own right, but also useful for helping interpret results from a parallel modeling activity - the Community Land Model (CLM) project.