The advancement of radar technology has been invaluable in improving meteorologists' ability to deliver accurate forecasts and tracking storms in real time.
One of the most significant radar advancements in recent memory was the development of dual polarization radar. The WAAY 31 Storm Tracker Early Warning Radar Network features dual polarity.
The three Doppler radars that make up the WAAY 31 StormTracker Early Warning Radar Network is the only radar system that can cover every square inch of North Alabama and provide earlier warnings with precise, real-time accuracy that can see storms other radars miss. Other radar systems, including the National Weather Service, have significant gaps in their radar coverage areas to see storms closer to the ground. With Doppler radars located in Muscle Shoals, the Decatur-Huntsville area, and Guntersville, the WAAY 31 Storm Tracker Early Warning Radar Network is the largest privately-held weather radar system in the United States.
Before dual polarization, weather radars only transmitted one pulse of energy to detect targets. This pulse is oriented horizontally and only provides details about the size of a target. With the addition of dual polarization, a second pulse is oriented vertically and is transmitted in addition to the original horizontal pulse.
The graphics below show how a typical radar with a horizontal pulse works, while the dual pol radar (second image) transmits and receives horizontally and vertically.
IMAGES COURTESY OF THE NATIONAL WEATHER SERVICE
This now provides meteorologists details on the shape of things it detects in addition to size. This additional information gives meteorologists more insight into what is occurring during active weather.
Improved Ability to Forecast
With dual polarization radar, meteorologists now have an improved ability to forecast flash flooding. They can also better discern specific precipitation types, such as between heavy rain and hail, or between snow and sleet.
Dual polarization radar also provides better detection of aircraft icing conditions. And perhaps the most significant development and benefit with the use dual polarization radar is the ability to detect non-meteorological items, such as insects, birds, or even more importantly, tornado debris.
IMAGE COURTESY OF THE NATIONAL WEATHER SERVICE
Benefits of Dual Pol Technology
- Improved accuracy of precipitation estimates, leading to better flash flood detection
- Ability to discern between heavy rain, hail, snow, and sleet
- Improved detection of non-meteorological echoes (e.g. ground clutter, chaff, anomalous propagation, birds, and tornado debris)
- Detection of aircraft icing conditions
- Identification of the melting layer (e.g. bright band)
The Debris Tracker
Here is a radar image from a tornado-producing storm near Columbus, Mississippi on February 23, 2019. This radar image is from the Correlation Coefficient product, better known as the "Debris Tracker." This product examines how uniform radar targets are in size and shape. Warmer colors indicate a strong correlation while cooler colors suggest that something on radar looks different from normal precipitation.
Notice the very dark blue and gray circle just to the northeast of Columbus. This circle is indicating that what is being detected by radar is not actual precipitation. Given that a Tornado Warning was issued for this storm, meteorologists could quickly conclude this was debris being lofted from a tornado on the ground.
Without dual polarization radar, the only way meteorologists can confirm a tornado touchdown is through public reports.
WAAY 31 Storm Tracker Early Warning Radar Network
The WAAY 31 Storm Tracker Early Warning Radar Network features dual polarization radar. This will allow our team to use products such as the Correlation Coefficient to provide more accurate, up-to-date information during severe weather, allowing you and your family to get to your safe place faster than ever before.