Improvements in weather radar rain rate estimates using a method for identifying the vertical profile of reflectivity from volume radar scans

A method for identifying the Vertical Profile of Reflectivity (VPR) when volume weather radar scans are available is presented. The first step in the identification of the VPR consists in averaging the vertical profiles of reflectivity observed near the radar. Then the Near Mean Apparent Vertical Profile of Reflectivity (NMAVPR) so obtained is applied in order to estimate the original VPR on each pixel. This is done by fitting the NMAVPR to the values of reflectivity observed over each pixel. As a consequence, an estimation of the reflectivity at ground level, which is provided by the lowest reflectivity value of the estimated VPR, is achieved. The results of a validation study based on using the first radar PPI as a reference are presented and analyzed in order to evaluate the performance of the method proposed. These results show that the method proposed manages to correct the critical overestimation of rain rate produced when the first PPI intercepts the bright band of stratiform rain, and also the underestimation produced when the first PPI intercepts precipitation falling as snow above the bright band.