The WSR-88D network is being upgraded to dual-polarization (DP) through use of a vertical waveform (Zv) that is compared to the horizontal waveform (Zh) to produce DP variable. The QVS website will be continually updated as new radars are upgraded. Data from DP radars are displayed individually and in native resolutions and polar format. These products are derived from Level 3 data from NCDC.
64 dual-polarization radars are ingested (as of 5/23/12). The lowest four tilts are displayed for each DP moment.
Note: to select different gauge networks for overlay, go to the gauge tab, select gauge networks and return to current tab.
"Legacy PPS" refers to conventional products from the Precipitation Processing System (PPS) computed in the ORPG and have resolution 1 km by 1 degree.
"DP QPE" refers to the new dual-pol products and have resolution .25 km by 1 degree. The various DP rainrate relations depend on the Hybrid Hydrometeor Classification algorithm. For more info and examples see: Rainfall Rate Relationships
For more info see: Warning Decision Training Branch Dual-Polarization Training and National Severe Storms Lab Polarmetric Doppler Radar.
TIP: The radar can only be selected using the lower-left window.
TIP: Gauges can be overlayed on accumulations by selecting networks on the "Gauge" tab and returning to the "Dual-pol" tab. The accumulated product must be then reselected. All HADS gauges are in after 2 hours.
TIP: Zooming in far enough allows the display of individual pixel/gate values. (Example)
Hybrid Hydrometeor Classification for KICT
Used to derive "legacy PPS" precipitation rates.
Hydrometeor classification algorithm derived from different tilts and used to determine which rain rate algorithm is used at each azimuth/range bin.
The specific differential phase is a comparison of the returned phase difference between the horizontal and vertical pulses.
A statistical correlation between the reflected horizontal and vertical power returns. It is a good indicator of regions where there is a mixture of precipitation types, such as rain and snow.
The differential reflectivity is a ratio of the reflected horizontal and vertical power returns. Among other things, it is a good indicator of drop shape.
Legacy rates are derived form the Level-3 Digital Hybrid Reflectivity (DHR) files from NCDC. Instantaneous rates, 1 hr and 24 hr accumulations are displayed.
Dual Pol rates are derived form the Digital Hybrid Precipitation Rate (DPR) files from NCDC. Instantaneous rates, 1 hr and 24 hr accumulations are displayed.
Within the mosaic tools, there is the ability to select showing either one product or the difference between any two products with the same units.