Analysis of a method for radar rainfall estimation considering the freezing level height

DOI: 10.3369/tethys.2010.7.03

Tethys no. 7 pp.: 25 - 39

Abstract

Quantitative precipitation estimation provided by weather radars plays a vital role in many hydrometeorological applications. The complexity of all the factors that contribute, on the one hand, to rainfall processes, and on the other hand, to the behavior of the energy beam emitted by the radar in its traverse through the atmosphere, mean that current estimates generally differ from the precipitation observed on surface. The aim of this study was to validate the SRI product (Surface Rain Intensity), which is a method of radar rainfall estimation that applies a correction considering a vertical profile of reflectivity (VPR). The VPR takes into account the freezing level height to make a correction in areas affected by the phenomenon known as “bright band”. Precipitation estimates obtained through this method were compared with other methods currently operational in the Meteorological Service of Catalonia in five representative episodes of convective and stratiform rainfall. In general, better results were obtained when compared with raingauge observations. Although this is a preliminary assessment that will have to be completed with more case studies, the results indicate good prospects for an operational use of this method.

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Partially funded through grants CGL2007-29820-E/CLI, CGL2008-02804-E/, CGL2009-07417-E and CGL2011-14046-E of the Spanish Ministry of Science and Innovation