The Inclusion of a Model to Simulate Carbon and Nitrogen Cycling into the Variable Infiltration Capacity (VIC) Model for Use in the Regional Arctic System Model (RASM)

The Regional Arctic System Model (RASM) is a coupled climate system model being developed by multiple institutions specifically for the Arctic region that includes the Variable Infiltration Capacity (VIC) model as its land component. Within VIC, multiple vegetation types are allowed within a grid box, but vegetation characteristics are prescribed and are not allowed to vary interannually or in response to changes in the regional climate system. As a first step in the integration of dynamic vegetation, we will present results from the implementation of a prognostic carbon-nitrogen cycle model, the CN as used in the National Center for Atmospheric Research (NCAR) Community Land Model, into the offline version of VIC. In particular, we will evaluate how long it takes for the modeled carbon and nitrogen pools in VIC-CN to reach equilibrium in a spin-up run. Modeled vegetation characteristics such as leaf area index from offline VIC-CN simulations will be compared to those derived from satellites. Furthermore, we will show how surface evapotranspiration and energy balance in VIC-CN compares to that in the default VIC and in situ observations. Soon, VIC-CN will be implemented into and tested in RASM.