May 24, 2005 to August 4, 2005
Project Description: 

REFRACTT is the Refractivity Experiment For H2O Research And Collaborative operational Technology Transfer.


REFRACTT includes scientific research and operational application goals. Both have the goal of greatly enhancing the observed field of water vapor over the nation thus leading to improved precipitation forecasts

The scientific goal is to utilize multiple radars and GPS receivers to simultaneously obtain very high resolution measurements of water vapor variability and transport in the convective boundary layer and to assess potential improvements these enhanced water vapor measurements may have in numerical model forecasts of quantitative precipitation.

The application's goal is to demonstrate the ability to collect radar refractivity data on the NEXRAD (WSR-88D) radars and to demonstrate the forecast value of this field to NWS forecasters. The ultimate goal is to implement radar refractivity measurements on the national network of operational radars.



1. High temporal and spatial resolution of near surface observations of water vapor will improve short term convective storm forecasting and quantitative precipitation forecasting.

2. 3-dimensinonal water vapor measurements obtained from combining radar refractivity and GPS slant range measurements will improve convective storm and quantitative precipitation forecasts.

3. Near-surface water vapor measurements will enhance our understanding of the exchange of moisture among soil/vegetation, land-surface, and boundary layer and determine the degree to which the boundary-layer moisture heterogeneity is related to land-surface heterogeneity.

4. The implementation of radar refractivity measurements on the national network of WSR-88D's with the new open radar data processor will be inexpensive and non-intrusive to other radar activities.

5. Accurate, path integrated, moisture estimates in the boundary layer can be obtained from dual-wavelength radar reflectivity measurements of clouds, resulting in horizontal and vertical moisture distributions.


Please see the REFRACTT06 page.