The History Of The Doppler Weather Radar
Doppler weather radar has come a long way since its beginning. In 1964, the first Doppler radar was commissioned by the National Oceanic and Atmospheric Administration (NOAA). The NOAA used the first 3-cm Doppler to receive radio signals from storms. The first few instances of “tornado tracking” were experimental, and soon the NOAA scientists realized that this system was not the best radar, since it was not big enough to receive all the necessary signals. In 1973, the NOAA’s recently upgraded 10-cm Doppler was observed by the National Severe Storms Laboratory (NSSL). For the first time in history, a tornado’s life cycle was captured both in data and on film. This data revealed the tornado’s circular motion, and the clouds inside the storm rotating around a centripetal point of rotation. This weather detector radar system would help increase the time for getting out severe weather reports to the residents of the area.
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.
