Towards better utilization of NEXRAD data in hydrology: an overview of Hydro-NEXRAD

Abstract

With a very modest investment in computer hardware and the open-source local data manager (LDM) software from University Corporation for Atmospheric Research (UCAR) Unidata Program Center, a researcher can receive a variety of NEXRAD Level III rainfall products and the unprocessed Level II data in real-time from most NEXRAD radars in the USA. Alternatively, one can receive such data from the National Climatic Data Center in Ashville, NC. Still, significant obstacles remain in order to unlock the full potential of the data. One set of obstacles is related to effective management of multi-terabyte datasets. A second set of obstacles, for hydrologists and hydrometeorologists in particular, is that the NEXRAD Level III products are not well suited for applications in hydrology. There is a strong need for the generation of high-quality products directly from the Level II data with well-documented steps that include quality control, removal of false echoes, rainfall estimation algorithms, coordinate conversion, georeferencing and integration with GIS. For hydrologists it is imperative that these procedures are basin-centered as opposed to radar-centered. The authors describe the Hydro-NEXRAD system that addresses the above challenges. With support from the National Science Foundation through its ITR program, the authors have developed a basin-centered framework for addressing all these issues in a comprehensive manner, tailored specifically for use of NEXRAD data in hydrology and hydrometeorology.

Analyses of the warm season rainfall climatology of the northeastern US using regional climate model simulations and radar rainfall fields

“…An important element of this work is the use of a multi-year radar rainfall data set developed from the Hydro-NEXRAD system [21]. Radar-rainfall estimates play a central role in flood forecasting [22] and in the detection of urban impacts on rainfall distribution [23].…”

Radar-rainfall estimation algorithms of Hydro-NEXRAD

“…This paper complements the overview of the Hydro-NEXRAD system given in Krajewski et al (2011) and the description of the metadata that allows users of the system to select hydrologically relevant cases .…”

“…Krajewski et al 2011). While these decisions were largely arbitrary, they were responsive to community demands.…”

“…While users order the available data and derived products, the process of data ingest continues independently, thus increasing the size of the dataset that is available for future use. Data ingest in the Hydro-NEXRAD system was halted in 2008 (see Krajewski et al 2011) when the federal agencies that operate the NEXRAD system switched data acquisition to the superresolution mode (Istok et al 2009). …”

“…Some of these modules include our modifications and improvements, but our focus here is on describing radar-rainfall estimation algorithms that produce rainfall maps delivered to users and completing the description of the Hydro-NEXRAD system given in Krajewski et al (2011) and Kruger et al (2011). A future study will comprehensively detail the Hydro-NEXRAD algorithms' performance.…”