The first Doppler weather radar was commissioned in 1964 by the National Oceanic and Atmospheric Administration, or NOAA. When scientists experimented with tornados, they quickly realized the 3-cm Doppler was not big or powerful enough to receive and track all of the needed information. They realized this one radar would need improvements.
The National Severe Storms Laboratory (NSSL) observed NOAA's upgraded 10-cm Doppler in 1973, which was able to track a tornado's life cycle. This data told scientists of the circular motion of a tornado's winds, as well as the centripetal point of rotation, which the inner clouds rotate around.
Scientists sought to increase their knowledge of how storms like these formed. One particular storm in May of 1973 cut right through the heart of Union City, Oklahoma. Union City lies in the center of the infamous "Tornado Alley" region of the United States. With the data received by the scientists, they were able to start planning upgrades and improvements of the Doppler weather radar so it could be a more reliable asset to the government and the residents.
The Doppler system maps weather radar by measuring the motion inside these very hostile storms. Over time, scientists discovered that tornadoes produce a unique signature; different from regular storms. And as time went on, they were able to recognize this pattern, which they later called the "tornadic vortex" signature.
Doppler weather radar improvements, including NEXRAD (Next Generation Radar), increased the warning time and the path prediction accuracy in storms with tornadic activity. Using NEXRAD, scientists nationwide are able to share data, giving a clearer picture of what to expect. In 2007, the National Weather Service picked up on tornadic cloud rotation and signature "hook-echo" patterns.
Residents of Enterprise, Alabama were warned to take cover, and a full eighteen minutes later the tornado touched ground. Thanks to NEXRAD, the previous, typical five minute warning time to get to a safe place finally saw a dramatic increase.
Eighteen minutes is ample time to gather family and emergency supplies and take shelter. It was also enough time for some commuters to seek shelter in a sturdy building and get off the streets. It is the goal of all meteorologists to increase the lead time to 20 minutes, saving many more lives in the process.
Doppler weather radar has come a long way. In the beginning, scientists hoped to save lives by getting the severe weather reports announced faster. Now, almost forty-five years since its birth, this one radar system is doing exactly that. |
