Radar-rainfall estimation algorithms of Hydro-NEXRAD

Abstract

Hydro-NEXRAD is a prototype software system that provides hydrology and water resource communities with ready access to the vast data archives of the U.S. weather radar network known as NEXRAD (Next Generation Weather Radar). This paper describes radar-rainfall estimation algorithms and their modular components used in the Hydro-NEXRAD system to generate rainfall products to be delivered to users. A variety of customized modules implemented in Hydro-NEXRAD perform radar-reflectivity data processing, produce radar-rainfall maps with user-requested space and time resolution, and combine multiple radar data for basins covered by multiple radars. System users can select rainfall estimation algorithms that range from simple ('Quick Look') to complex and computing-intensive ('Hi-Fi'). The 'Pseudo NWS PPS' option allows close comparison with the algorithm used operationally by the US National Weather Service. The 'Custom' algorithm enables expert users to specify values for many of the parameters in the algorithm modules according to their experience and expectations. The Hydro-NEXRAD system, with its rainfall-estimation algorithms, can be used by both novice and expert users who need rainfall estimates as references or as input to their hydrologic modelling and forecasting applications.

Spatial Analysis of High-Resolution Radar Rainfall and Citizen-Reported Flash Flood Data in Ultra-Urban New York City

“…This processing must contend with radar problems such as the radar hitting the ground, hailstones, conversion of three-dimensional (3D) radar scans into two-dimensional (2D) rainfall maps, and range errors associated with variations with the vertical variation of reflectivity data. The Hydro-NEXRAD algorithms have been shown to successfully process radar reflectivity data to account for the Z-R relationships and above issues [35]. A 15-year period (2001-2015) of warm-season (April-September) radar rainfall fields was produced for the KDIX radar.…”

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

“…Analyses are based on simulations using the weather research and forecasting (WRF) model for the five warm seasons (April-September) from 2003 to 2007 and highresolution radar-rainfall fields for the study region from the Hydro-NEXRAD system for the same time period. The rainfall climatology of this study region is complex due to the effects of mountainous terrain [6][7][8], land-water boundaries [9,10] and urbanization [11,3,[12][13][14][15][16][17][18]. A central objective of this study is to characterize the warm season rainfall climatology of the New York-New Jersey metropolitan region using high-resolution radar rainfall fields and regional climate model simulations.…”

“…Hydroclimatological applications have been slower to develop due to the short record lengths and uncertainties in estimation properties (see [24,23,25]). The Hydro-NEXRAD system [21,14] provides a platform for developing long-term rainfall data sets with error properties that are well characterized. In this study, we use the Hydro-NEXRAD system with ''standard algorithms'' for Z-R conversion and quality control.…”

A diagnostic study of spectral multiscaling on spatio-temporal accumulations of rainfall fields based on radar measurements over Iowa

“…Those radars are located in Des Moines (KDMX) and Davenport (KDVN), Iowa, La Cross (KARX), Wisconsin, Minneapolis (KMPX), Minnesota, Sioux City (KFSD), South Dakota, and Omaha (KOAX), Nebraska (Fig. 1), providing reflectivity data every 5-10 min with spatial resolution of 1 km in range and 1 degree in azimuth, which are converted to rain rate accumulations (STARR) using a variety of (operational and research) algorithms [16,39].…”

“…The second record is produced by the Hydro-NEXRAD software system, abbreviated by HNX-1 [19][20][21]39], with higher resolution than Stage-IV, both spatially and temporally. The HNX-1 product is spatially resolved on the same projection grid (HRAP) as Stage-IV, but 4 2 -denser, comprising 1 km  1 km square pixels exactly inscribed on the HRAP grid.…”