P59 Sea ice enhancements to the Noah LSM in Polar WRF

Hines, Keith M., D. H. Bromwich, L. Bai, Ohio State University, J. G. Powers, and K. W. Manning, National Center for Atmospheric Research

Sea ice enhancements are included in the polar-optimized code for the Weather Research and Forecasting model known as "Polar WRF". Inspired by the Arctic System Reanalysis and the Antarctic Mesoscale Prediction System, Polar WRF is developed and provided to the scientific community by the Polar Meteorology Group of The Ohio State University's Byrd Polar Research Center as a code supplement to the standard WRF release from the National Center for Atmospheric Research. The optimizations for Polar WRF include changes to the sea ice and land treatment used with the Noah land surface model. Starting with version 3.4, sea ice and land ice routines are moved outside the soil-based landuse treatment by Noah. The polar optimizations allow users to specify sea ice thickness rather than using the default thickness 3 m. Therefore, recent Arctic sea ice thickness datasets such as those produced at the University of Illinois at Urbana-Champaign or the University of Washington can be applied. Specified variable snow cover over sea ice and specified variable sea ice albedo can also be treated. Supplemental algorithms designed for use with the WRF Preprocessing System are available to implement sea ice fields. They also allow users to represent an idealized seasonal progression of Arctic sea ice albedo. These sea ice capabilities with the Noah land surface model in Polar WRF 3.4.1 are tested in comparison to summer and winter 1998 observations over the pack ice at the Surface Heat Budget of the Arctic Ocean (SHEBA).