Overview

The lack of detailed, high–resolution water vapor measurements in the atmospheric boundary layer is one of the primary limiting factors in being able to predict convection initiation and produce accurate quantitative precipitation forecasts from numerical weather prediction models. During the summer of 2006, scientists took an important first step in addressing the need for an improved national, high–resolution moisture field by conducting the Refractivity Experiment For H20 Research And Collaborative operational Technology Transfer (REFRACTT).

This effort is directed, not only toward improving our understanding of near–surface water vapor variability and the role it plays in the initiation of thunderstorms, but also on building operational advocacy for installing a new refractivity moisture retrieval technique on the national network of NEXRAD radars. This novel technique is based on measuring changes in the speed of radar signals to fixed targets caused by refraction, which in turn reveals variations in the atmospheric moisture content. REFRACTT yielded a wealth of data that are being analyzed now.