Satellite-derived wind, cloud, and surface products at Direct Broadcast sites in the Antarctic and Arctic

For the past three years, Moderate Resolution Imaging Spectroradiometer (MODIS) data has been used to generate near real-time wind information over both polar regions. Eight numerical weather prediction centers worldwide have demonstrated that the MODIS winds have a positive impact on global weather forecasts. Six of these centers are assimilating the MODIS polar winds in their operational forecast systems, with the other two planning on operational use in the near future. However, much of the wind information cannot be generated fast enough for use in regional forecast models, primarily because of the delay in obtaining the MODIS data. Direct broadcast sites provide the opportunity to improve the timeliness of the wind data and to provide local forecasters with real-time products.

As of March 2005, polar wind data covering much of Antarctica has been generated with MODIS data received by the U.S. National Science Foundation's direct broadcast system in McMurdo, Antarctica. All the processing is done in McMurdo, and only the wind data and plots are transferred back to the mainland U.S. Recently other real-time products have been implemented, including a cloud mask, cloud top pressure, cloud particle thermodynamic phase, snow/ice surface temperature, and snow/ice surface albedo. The cloud products are part of the International MODIS/AIRS Processing Package (IMAPP), which is also used for processing the raw MODIS data. Additional products are planned, including cloud optical depth and particle size, surface radiative fluxes, and sea ice motion. Real-time products generated at McMurdo are available at http://stratus.ssec.wisc.edu/products/db/mcmurdo.

This first implementation of the wind processing at a direct broadcast site lays the groundwork for providing wind information for numerical forecast models and local forecasters faster than our current processing system. Potential Arctic DB sites are being investigated to complement the Antarctic site, particularly Fairbanks, Alaska and Tromsų, Norway.