Enhancement of Polar WRF Arctic atmospheric and surface processes

Accelerated by the record summer sea ice minima in 2007 and 2008 and growing interest in Arctic climate, simulations of Arctic conditions with the Weather Research and Forecasting model (WRF) are investigated. The goal is to examine key characteristics of weather patterns in the Arctic, Arctic river basins, as well as surrounding lower latitudes in order to validate the use of WRF in this area. The standard version of WRF 3.0 is used to simulate Arctic conditions during 2007, including the months of August and December, throughout the Arctic System Reanalysis (ASR) domain. The 2-way nested domains are centered on the North Pole, with the inner domain extending 10,800km in the east-west and north-south directions with 60km resolution. The boundary conditions are specified by the National Centers for Environmental Prediction (NCEP) Final Analysis data. The simulations are performed in 48 hour increments initialized daily at 0000UTC, with the first 24 hours discarded for model spin-up. WRF results are compared with surface observations from the National Climatic Data Center and upper level observations from the University of Wyoming's Department of Atmospheric Science.

Overall, preliminary results of WRF simulations of temperature, moisture, pressure, and winds agree well with surface observations for August 2007 and December 2007. However, differences between the model and observations exist at some locations due to apparent local topographic effects. Likewise, some synoptic features (e.g., Alberta Clippers) appear to be misrepresented, leading to differences between the model simulations and observations.

Future work will include analysis of surface and upper level characteristics using a polar-optimized version of WRF (Polar WRF) for the entire year of 2007. In addition to using previous Polar WRF improvements to the Noah land scheme and fractional sea ice, sea ice thickness will be specified as thick multiyear sea ice or thin seasonal sea ice and allowed to vary for the entire year accordingly. Similarly, seasonal progression of sea ice albedo and treatment of Arctic melt ponds will be addressed to ensure proper albedo over all surfaces. This analysis and enhanced description of atmospheric and surface processes in WRF will produce a robust model that will be used to simulate Arctic conditions for the entire ASR period. Furthermore, this newly optimized version of Polar WRF will be used for outreach between scientists at the Byrd Polar Research Center of The Ohio State University and students at the Columbus Zoo and Aquarium through the Polar Frontier Project.