It is a rainy morning in the Valley and the first thing many of you did when you woke up was look to see where the showers were using the Youngstown weather radar. However, have you ever stopped to wonder how radar works?
The truth is that radar is an incredible technological advancement that provides meteorologists with endless information. Let’s learn about it.
First off, RADAR is an acronym
That’s right. The word “radar” stands for RAdio Detection And Ranging (RADAR) and, like many technological advancements, traces its origins back to military applications. Radar as we know it was first used to detect enemy aircraft during World War II.
During the war, the entire premise of radar technology was top secret to prevent the enemy from flying under the radar during bombing raids.
In fact, the British developed a classification of different radar wavelengths that was purposefully confusing and unfortunately that has carried over today so it was difficult to learn those different wavelengths in the past. For the purpose of this article, you will only need to know about S-band radar which has a wavelength of around 10 centimeters.
How does a radar work?
It might not be a secret that radars require copious amounts of energy to work. The National Weather Service NEXRAD radars require 750 kilowatts to operate. The basics of a radar are relatively simple. There is traditionally a stand for the radar, a radar dish, a transmitter, and a radar dome. There are some more sophisticated parts, but these are the basic ones that help the radar function.
The radar transmitter emits an electromagnetic pulse that is focused by the radar dish. The stand the radar sits on helps to elevate the signal above buildings and trees. The radar dome helps to protect the radar dish from wildlife and weather.
Once the radar transmits the pulse of energy, it then begins to “listen” for something to bounce off of. In the case of meteorology, scientists are most of the time looking for rain or snow but radar can detect multiple objects.
When the energy from a radar interacts with an object, like a raindrop, some of that energy is reflected back to the radar.
How do we know the radar is detecting rainfall?
The complete truth is that you always need ground truth to be 100% confident in what the radar is detecting, but recent upgrades to radar technology make it easier than ever before to have a high degree of confidence in precipitation types.
In 2013, all of the National Weather Service (NWS) radar were upgraded to polarimetric radars. This is a fancy word, but polarimetric means that the radar can transmits wavelengths in the vertical and horizontal plane whereas standard radars only transmitted in the horizontal.
So what does this mean to you? Well, this improvement allows meteorologists to determine the size and shape of objects that are shown by the radar.
Therefore, using polarimetric radar technology, meteorologists can determine the differences between precipitation types (rain, snow, hail, etc.) and even the difference between rain and biological matter such as birds and bugs.
What are some different types of radar?
I am been fortunate enough to encounter several different radar types throughout my studies and travels. Below are a couple of unique examples that I have been a part of.
Colorado State University – Chicago Illinois Radar (CHILL)
The CSU CHILL radar is one of the most unique radars in the world. The radar dome is an air tight dome instead of a plastic one and the radar features a dual antenna which can transmit at multiple wavelengths. This radar is used mainly to detect severe thunderstorms and snow but it has also been used in fire weather events in recent years.
Colorado State University SeaPol Radar
Another unique type of radar that I was able to actually build was the CSU SeaPol Radar. This radar was actually mounted on a ship and was used to detect thunderstorms at sea for over a month. It features a stabilizer that keeps the antenna level with the boat at all times despite the waves.