Description:

Based on extensive experience with mesoscale modeling in the polar regions by the Polar Meteorology Group of the Byrd Polar Research Center at The Ohio State University, the Weather Research and Forecasting model (WRF) has been modified for use in the Polar Regions (referred to as the Polar WRF). A development approach is adopted similar to that used previously to implement the Polar version of the PSU/NCAR fifth generation mesoscale model (Polar MM5). The key modifications for Polar WRF are:

• Revised cloud / radiation interaction
• Adapted explicit ice phase microphysics
• Optimal turbulence (boundary layer) parameterization
• Implementation of a fractional sea ice description in the Noah LSM
• Improved treatment of heat transfer for ice sheets and revised surface energy balance calculation in the Noah LSM

A model development study of Polar WRF simulations over Greenland has been performed, and the results are described in the article provided below. Development studies are underway for Arctic Ocean (SHEBA site), Arctic land (ARM sites in Alaska), and Antarctica.

Polar WRF is used by forecasters as part of the National Science Foundation sponsored Antarctic Mesoscale Prediction System (AMPS; link provided below) to meet the operational and logistic needs of the United States Antarctic Program (USAP). Under a collaborative project with the Polar Meteorology Group, AMPS simulations are performed at the National Center for Atmospheric Research twice per day (00Z and 12Z initializations), and cover progressively finer domains ranging from 60-km (covering most of the Southern Hemisphere) to 2.2-km (covering the region immediately surrounding McMurdo Station, the base of USAP operations). A 60-km resolution version of the Polar WRF is run here at the Byrd Polar Research Center once per day as a backup to AMPS (link provided below).

Status of Polar WRF:

Polar WRF Now Available (May 29, 2008):

As you probably know, WRF 3.0 was released by NCAR in April 2008. The only polar physics available in that standard release is the Morrison mixed phase microphysics (developed especially for Arctic stratus clouds and tested by Bromwich et al. (2008)), but some care is needed in setting the required parameters, according to Amy Solomon of NOAA Earth System Research Laboratory in Boulder, Colorado. We have now implemented all other polar physics into WRF3.0 and the modified code is undergoing final testing. The fractional sea ice description developed by the Polar Meteorology Group (Le-Sheng Bai and Keith Hines) has been ported to the NOAH Land Surface Model (LSM) included in WRF 3.0, as well as the modifications to the NOAH LSM required for ice sheets, as described by Hines and Bromwich (2008). The Polar WRF 3.0 code is now available upon request to interested researchers; contact Dr. David Bromwich for details. The Polar WRF 3.0 code cannot be guaranteed to work under all circumstances, so feedback will help iron out any remaining kinks. We will provide assistance with code use to the level consistent with our ongoing responsibilities. The goal, according to Jordan Powers of NCAR, is to make all polar physics available in the next standard release of WRF scheduled for March 2009. This will be a contribution to the International Polar Year (March 2007-March 2009).

August 5, 2008:

Version of Morrison microphysics scheme in WRF 3.0 yields large surface warm biases over interior Antarctica and the Arctic SHEBA site during winter.

Testing of Polar WRF:

• Greenland ice sheet: evaluation completed and described in Hines and Bromwich (2008).
• SHEBA (Surface Heat Budget of the Arctic Ocean) site in the Beaufort Sea in 1997-1998: evaluation has been completed and manuscript by Bromwich et. al (2008) has been submitted and undergone one round of revisions.
• Arctic land areas (Department of Energy Atmospheric Radiation Monitoring (ARM) sites at Barrow and Atqasuk, Alaska): work underway by Keith Hines and David Bromwich.
• Antarctica: work underway by Elad Shilo, Francis Otieno, and David Bromwich. In addition, work on this topic has been ongoing at NCAR (primarily) as part of the Antarctic Mesoscale Prediction System (AMPS) by Kevin Manning and Jordan Powers.

August 18, 2008:

Based upon request, Polar WRF 3.0.1 has been sent to the following individuals: