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Items 2007 NSSL invites public to participate in hail observation program
On the heels of the Winter Hydrometeor Classification Ground Truth Program, NSSL is again calling on the public to participate in their science and research as part of the Hail Size Discrimination Experiment (HaSDEx).
Hail observations throughout the duration of thunderstorm events occurring within 90 miles of Norman, OK are needed from as many people in as many places as possible. Volunteers are requested to document date, time, location and the size of hail. The Norman National Weather Service Forecast Office is again assisting by providing a link to the project on their website.
During HaSDEx, researchers will merge observations with data from the dual-polarized KOUN radar to investigate the relationship of polarimetric variables to hail size. The information will be used to refine hail detection algorithms being developed to diagnose storm characteristics and intensity and improve warnings for hail producing storms.
HaSDEx is different from other public cooperative observation programs because the volunteers remain anonymous and make no long-term commitments. HaSDEx is also focused on hail only, while other programs document rainfall amounts, temperature, and other general information.
NSSL researchers have been developing dual polarization radar for more than 20 years. NSSL's research radar, KOUN WSR-88D, was upgraded with dual polarization capabilities in the spring of 2002. KOUN is the prototype radar for a future upgrade to the existing nationwide network of WSR-88D's, expected to begin in 2009.
Background: Dual-polarization radars send out horizontal and vertical pulses of radio waves and can identify the specific location of hail, estimate hail size, and track hail swaths. Conventional radars only send out horizontal pulses and are limited to estimating the probability of hail at any particular location within a storm.
Significance: Data collection efforts involving the public brings science home by increasing awareness of severe weather hazards, severe weather safety, and NSSL’s research efforts to better forecast and warn of these events.
4/24/07