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Polarimetric Radar Applications and Data Analysis
The Dual Pol Hydrometeor Classification Algorithm recognizes different types of precipitation within radar data.
 "Dual Pol WSR-88D 1-hr rainfall estimate (left) vs. legacy @SR-88D estimate (right)")
Dual Pol WSR-88D 1-hr rainfall estimate (left) vs. legacy WSR-88D estimate (right). The right-hand image was a significant overestimate due to hail contamination; the Dual Pol product provided a much better estimate. Larger image
Dual-Pol Based Surface Precipitation Type Algorithm
NSSL researchers are working on an algorithm to integrate data from surface temperature sensors, numerical weather prediction model thermodynamic output, and dual-polarimetric radar hydrometeor classification algorithm output and produce a surface precipitation type product. This technique shows promise in accurately depicting regions of freezing rain, snow, and rain at the surface, aiding aviation ground operations during winter storms.
Winter Hydrometeor Classification Ground Truth Program/Hail Size Discrimination Experiment
NSSL researchers have partnered with the public in and around Norman, OK, to gather information on the forms of hail and winter precipitation observed at different locations within range of the Polarimetric Doppler Radar at NSSL. The Winter Hydrometeor Classification Ground Truth Program and Hail Size Discrimination Experiments collect observations from members of the public for use by scientists in comparing radar products with observed weather.
Polarimetric Radar in Warning and Decision-Making
To test the utility and added
value of polarimetric radar products in an operational environment, data from
the Norman, Oklahoma (KOUN) polarimetric Weather Surveillance Radar-1988 Doppler
(WSR-88D) were delivered to the National Weather Service Weather Forecast Office
(WFO) in Norman as part of the Joint Polarization Experiment (JPOLE 
).
KOUN polarimetric base data and algorithms were used at the WFO during the decision-making
and forecasting processes for severe convection, flash floods, and winter storms.
The delivery included conventional WSR-88D radar products, base polarimetric
radar variables, a polarimetric hydrometeor classification algorithm, and experimental
polarimetric quantitative precipitation estimation algorithms. Polarimetric
data aided WFO forecasters during several periods of heavy rain, numerous large-hail-producing
thunderstorms, tornadic and non-tornadic supercell thunderstorms, and a major
winter storm.
Estimating the Impact of Sensitivity Loss on WSR-88D Due to Dual-Pol Upgrade
The planned upgrade of the WSR-88D network to include dual-polarimetric capabilities is expected to result in a loss of about 3 dB in sensitivity per channel. In order to better estimate the impact of this sensitivity loss, NSSL scientists performed case study and real-time simulations and proposed techniques to recover some of the lost velocity information.
