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SFMR Surface Wind Improvement in Heavy Rain Conditions

Principal Investigator:

Project Member:

Collaborating Scientists:

Christopher Landsea - National Hurricane Center

Michael Brennan - National Hurricane Center



The objectives of this project include the following:

  • Quantify the bias between the SFMR surface winds and the dropsonde surface-adjusted winds in the presence of rain
  • Develop a bias correction model to apply in semi real-time for tropical cyclone forecasting applications
  • Use independent sources of rain (i.e. NOAA Tail Doppler radar, Precipitation Imaging Probe) to determine the correct rain rate in relation to atmospheric absorption
  • Apply corrections to the rain-absorption and wind-emissivity relationships to provide updates to the geophysical model function
  • Analyze the results of the update to the current operational and the bias-corrected versions of the wind speed in the presence of rain


Several milestones have been reached and include:

  • A large database of SFMR and GPS dropsonde pairs has been developed and includes data from 1999 through 2012.  This database includes over 3000 pairs.
  • The bias correction model was used at the National Hurricane Center during the 2012 hurricane season.  The forecasters found the bias correction useful in making their predictions.
  • A new Z-R relationship was developed from the NOAA Tail Doppler Radar to apply to the SFMR
  • An updated GMF has been developed and will be monitored in research mode by this project's team members during the 2013 hurricane season
  • The Weather Channel will be using the bias correction model during the 2013 hurricane season in some of their on-air discussions of hurricane surface winds

Future Goals:

The remaining objectives for this project include:

  • Apply the updated GMF to the operational aircraft in time for the 2014 hurricane season
  • Develop a secondary bias correction for extreme rain situations where data are limited

  • Uhlhorn, E. W. and P. G. Black, 2003: Verification of Remotely Sensed Sea Surface Winds in Hurricanes. Journal of Atmospheric and Oceanic Technology, 20, 99-116.
  • Uhlhorn, E. W., P. G. Black, J. L. Franklin, M. Goodberlet, J. Carswell, and A. S. Goldstein, 2007: Hurricane Surface Measurements from an Operational Stepped Frequency Microwave Radiometer. Monthly Weather Review, 135, 3070-3085.
  • Franklin, J. L., M. L. Black, and K. Valde, 2003: GPS Dropwindsonde Wind Profiles in Hurricanes and Their Operational Implications. Weather and Forecasting, 18, 171-181.

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