Gauge-Adjusted Radar Rainfall
Real-time Data Service
OneRain uses real-time radar data from its vendors and real‑time rain gauge data from its customers to calibrate the radar data and deliver rainfall data immediately back to the customer in a variety of formats for decision support.
Historical Data Service
The OneRain Harbor is used to provide data for post-event analysis or model quality datasets. OneRain extracts radar data from its database, receives or finds data for the appropriate study area, QA/QCs both data sets, calibrates the radar, and delivers the results to the customer in an agreed format. Delivery options include basin averages, animations, comma-delimited text, spreadsheet, reports, or model-specific formats.
Gauge-Adjusted Radar Rainfall (GARR) marries rain gauge estimates at a point with the spatial distribution information from the National Weather Service NEXRAD radars to give us information about what is happening between the gauges. The rain gauge data are used to calibrate the radar and generate rainfall estimates for each 1km or 2km pixel, depending upon the resolution of the data that is used. GARR data is used in flood warning, runoff modeling, I/I studies, litigation, real-time control, design storms, and National Pollutant Discharge Elimination System (NPDES) compliance activities.
OneRain collects and stores a nationwide 
mosaic of radar information every five and fifteen minutes. Historical records of the national mosaics are maintained in the OneRain Harbor (databases):
- 2km, 15-minute data from 1993 to the present
- 1km, 5-minute data from 2002 to the present
OneRain’s customers often supply the rain gauge data used in the radar rainfall analysis or OneRain will try to obtain gauge data from other sources. In a real-time operation, OneRain uses data supplied by the customer from a real-time telemetry system.
