Unlock more accurate rainfall estimates with GARR calibrated to your local rain gauges, using the same core concepts behind the MRMS Radar QPE with Gauge Bias Correction approach.
What GARR Delivers
Gauge-Adjusted Radar Rainfall (GARR) blends high-resolution radar data with localized rain-gauge measurements to correct systematic radar bias and sharpen rainfall totals where you actually operate.
The result is a 1 km × 1 km rainfall grid, updated hourly, that is tuned to local ground truth instead of relying on radar alone.
Why Local Gauge Calibration Matters
Radar by itself can over- or underestimate rain due to beam height, attenuation, and storm structure; local gauges capture what truly fell at the surface.
By continuously comparing radar estimates to nearby gauges and correcting the bias, GARR provides more reliable inputs for flooding, drainage, and stormwater decisions.
How the Calibration Works
Each hour, rain gauges are first quality controlled to remove bad data from frozen precipitation, late reports, or anomalously high/low values.
The difference between radar-estimated rain and gauge-measured rain is calculated at each valid gauge, then smoothly interpolated out to surrounding pixels using a distance- and density-aware weighting method, creating a bias field that is subtracted from the original radar rainfall.
Smarter Use of Sparse Gauges
The algorithm automatically adjusts how much it trusts gauges versus radar depending on how many gauges are nearby, giving more weight to gauges in dense networks and more weight to radar where gauges are sparse.
Repeated cross-validation each hour identifies and removes suspect gauges, minimizing error and keeping the calibration robust during real-world events.
Benefits for Your Users
More accurate rainfall maps for design storms, compliance reporting, and flood risk assessment.
Consistent, multi-hour accumulations (1–72 hours) built from a bias-corrected one-hour foundation, ideal for hydrologic modeling and operational decision support.
Contact us at support@highresgarr.com