Evaluating NEXRAD multisensor precipitation estimates for operational hydrologic forecasting

Next-Generation Weather Radar (NEXRAD) multisensor precipitation estimates will be used for a host of applications that include operational streamflow forecasting at the National Weather Service River Forecast Centers (RFCs) and nonoperational purposes such as studies of weather, climate, and hydrol ogy. Given these expanding applications, it is important to understand the quality and error characteristics of NEXRAD multisensor products. In this p aper, the issues involved in evaluating these products are examined through an assessment of a 5.5-yr record of multisensor estimates from the Arkansa s-Red Basin RFC. The objectives were to examine how known radar biases mani fest themselves in the multisensor product and to quantify precipitation es timation errors. Analyses included comparisons of multisensor estimates bas ed on different processing algorithms, comparisons with gauge observations from the Oklahoma Mesonet and the Agricultural Research Service Micronet, a nd the application of a validation framework to quantify error characterist ics. This study reveals several complications to such an analysis, includin g a paucity of independent gauge data. These obstacles are discussed and re commendations are made to help to facilitate routine verification of NEXRAD products.