WARNING APPLICATIONS RESEARCH

image of a flooded house

Aggregate hailstone approximately six inches in diameter. The Warning Applications group works on systems that help forecasters detect, monitor and predict the occurrence of severe weather.

 

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Phased Array Radar (PAR)

The NSSL multi-sensor hail swath application display

Phased Array Radar images are updated much more frequently than conventional NEXRAD radars, giving scientists a more detailed and timely view of the development of severe weather.

View a simulated comparison of the evolution of a Phased Array Radar display, vs. a current NEXRAD radar display. (animated gif, 2 Mb)

Working in collaboration, NSSL scientists and engineers from the Radar and Warning Research and Development Divisions are involved in collecting and analyzing meteorological data using the Phased Array Radar (PAR). The PAR's rapid volumetric updates (on the order of 1 minute, versus approximately 5 minutes for WSR-88D) provides scientists and forecasters a better understanding of storm development, evolution and decay.

NSSL Warning Applications scientists are focusing on the added benefit of having more rapid three-dimensional radar scans. Current WSR-88D volume scans take approximately 5 minutes between updates. This provides the forecaster with "snapshots" of storm behavior. This also means that the top of the storm is sampled nearly 5 minutes after the bottom of the storm is sampled, making the vertical profile of storm features difficult to identify.

In contrast, the PAR updates a volume of radar data in approximately one minute, which is more like watching a "movie". Users will be able to track features from one scan to the next with greater accuracy. Additionally, the top and bottom of the storm can be sampled at about the same time, which provides better vertical continuity of features.

NSSL scientists anticipate that the rapid updates will result in increased precision of existing radar algorithms by reducing time-association and vertical-association errors. New algorithms are under development that take advantage of features that were only intermittently sampled by the WSR-88D (i.e., mesocyclones, tornadic vortex signatures, descending reflectivity cores, three-body scatter spike, etc.), and to more efficiently handle the increased data flow. NSSL researchers will also provide input for adaptive scanning strategies for sampling severe weather using the PAR.