You’re already familiar with the traditional tools for collecting weather information. But don’t overlook the importance of radar technology in weather forecasts. Learning about weather radars helps you understand comprehensive forecast programs on televisions.
You might wonder, “how does a weather radar work?” Continue reading to discover what a weather radar is, how it works, and why it’s critical in meteorology.
What is a Weather Radar?
A weather radar is an essential tool meteorologists use to monitor precipitation and predict the weather. It allows them to understand the current conditions for higher accuracy in forecasts.
Radar is an acronym for Radio Detection and Ranging, which operators initially used in World War II to recognize enemies. Later on, they found out that rain and other kinds of precipitation resulted in false radar echo on-screen.
Today, new radars are also known as the Doppler weather radar. They transmit electromagnetic pulses into the air to look for precipitation and measure different variables. These tools also determine whether the precipitation is hail, snow, or rain.
The meteorologist obtains this information as the radar pulses bounce back. They analyze the data to check specific locations where severe thunderstorms may occur. Hence, the weather radar can be a valuable tool to protect property and human life.
What are the Parts of a Weather Radar?
The weather radar has five primary parts. And it’s essential to understand what each component does to know how the weather radar works.
The transmitter is the part of the radar that produces the pulse. It must have the capacity to create the necessary power to detect precipitation.
The radar processor is the processing program that gathers and analyzes the data that comes back to the antenna. It uses details like the signal’s distance for accurate forecasts.
The receiver has a simple role. It detects and magnifies the signal that the radar processor gathers.
The antenna is also known as the radar dish, and it includes a larger antenna and a layer that protects it from degrading. The radar dish rotates to obtain data from different locations as the antenna emits pulses into the air.
The parabolic antenna is also responsible for receiving the pulses that reflect. Energy waves scatter when it catches an object, and some should go back to the antenna.
Ideally, there are two display systems. One is directly linked with the radar, and the other is for broadcasters’ use.
The Weather Company’s EEC Weather Radar Software directly shows the data from the radar. Its interface lets meteorologists control the antenna elevation, volume, speed, and surveillance mode.
For representations for broadcast, the IBM Max broadcast system shows standard parameters. These radar moments include the spectrum width, reflectivity, correlation coefficient, and hydrometeorological hazards.
How Does Weather Radar Work?
All types of radar work the same. They all include an antenna that releases a beam of radio waves that scatter if they bounce off objects like snow or rain. The scattered beam of energy bounces back with bigger objects reflecting more.
The modern weather radar provides images accessible on the internet, mobile apps, and television. It plots the reflectivity differences on a radar map so that meteorologists get a clue of the precipitation within the radar’s range.
But the Doppler weather radar is different from the typical modern radars. Thanks to technological advancements, it can also determine how the precipitation looks like through its position and shape.
Doppler weather radars not only measure the reflectivity of the precipitation. They also obtain wind speed readings to predict tornadoes and heavy rain. The precipitation’s velocity is also accessible on the radar image.
The National Weather Service started using the Doppler effect in the 1980s. Through it, people are informed about the tornadoes and wind gusts developing.
Before the Doppler radar, experts had to detect a so-called “hook echo” when looking for tornadoes in a strong thunderstorm. And it wasn’t always successful because not all tornadoes have hook echoes.
The weather radar also works to detect swarms of insects, wildfire smoke, and flocks of birds. It can also sense tragedies, like the 2003 incident where the Space Shuttle Columbia disintegrated in Texas.
Why are Weather Radars Essential?
The continuous advancement of weather radar is vital to make real-time weather reports more efficient. Weather radars are perhaps the best weather-predicting instruments to determine upcoming precipitation.
It’s also essential to monitor how severe the precipitation is, making residents more cautious. Weather radars can show the probability of danger while it hasn’t approached yet. So, they can prepare for anything from light precipitation to damaging wind gusts.
News stations and commercial television outlets rely on the radar for their forecast strategy. It keeps viewers informed so they know when to prepare or evacuate. Television stations also use radar data to prepare media personnel for possible power outages.
What are the Kinds of Weather Radar Bands?
One can categorize the Doppler radar based on the wavelengths. There are three types to remember when it comes to the basics of radars.
- Wavelength: 8-15 cm.
- Frequency: 2-4 GHz, but some operate within 3.0-3.8 GHz.
These band weather radar systems provide more room for analysis than the C-band because of their longer wavelength. This 10-cm wavelength weather radar passes through diverse precipitation bands and goes higher while moving farther.
This radar beam direction may lead to unsuitable analysis. That’s because what meteorologists analyze in the air is not always the same on the ground level. But they can still see and examine precipitation returns in a far area, so they are more expensive than common weather radars.
- Wavelength: 4-8 cm.
- Frequency: 4-8 GHz, but some operate within 5.3-5.6 GHz.
C-band radars are applicable to precipitation analysis that is medium to long-range. They are best for short-range weather observations since the wavelength penetrates to moderate precipitation bands.
It can identify beyond the closest band, but it weakens or attenuates more than the S-band. That means the C-band radar cannot precisely label precipitation rates.
C-band weather radars are more expensive than X-band radars. But they are cheaper than S-bands.
- Wavelength: 2.5-4 cm.
- Frequency: 8-12 GHz.
The 3 cm X-band radar has the shortest wavelength among other bands, making them more sensitive to lightweight objects. It can be vulnerable to attenuation of radar returns because the radar waves do not penetrate through heavier precipitation bands.
Meteorologists may experience difficulty monitoring beyond the precipitation band. It’s more challenging to determine what is approaching when they only use x-band radars.
The radar dish of the X-band is typically smaller than the C-band and S-band, which use a larger antenna. Therefore, X-band is the cheapest weather radar among the three.
Where are They Used?
You can find x-band radar on trailers and trucks since they have a small size. The mobile antenna dish can approach the area with heavy precipitation for more accurate analysis. Driving it close to the storm allows it to depict severe weather at the ground level.
Radar networks of x-bands can also be in a fixed location. Doing this lets meteorologists know what’s behind the high intensity of the precipitation. It also allows them to get a realistic depiction of the ground-level conditions.
What is Dual Polarization Radar?
Doppler radar isn’t the latest upgrade on weather radars. The dual-polarization radar is another radar with improved detection abilities. Here, the pulses of radio waves are not just in a horizontal direction but also in a vertical direction.
The weather radar imagery and colors become clearer because meteorologists can recognize the shape of objects in the air. Dual polarization technology can identify when airborne tornado debris is on the ground and the type of precipitation falling.
Dual-pol radar not just lets you detect a tornado. It also shows the area of clear air, objects in the atmosphere, and similarly-shaped raindrops. The colors blue, green, and red show these elements on the correlation coefficient image.
The encircled image on the right from NOAA is called a debris ball, which indicates a tornado on the ground. Notice how you won’t find the same picture on the Doppler radar to the right.
One hindrance to the dual polarization’s performance is the Earth itself. It climbs high off the ground while the beam goes farther because of the Earth’s curvature.
Radars can only monitor precipitation over 10,000 above the surface once the beam is only a few miles away.
Weather coverage on television usually employs velocity imagery to check where a tornado is in thick clouds and precipitation. It includes red colors to show that the winds are moving away and green to show the winds moving closer.
What Do the Weather Radar Colors on a Radar Screen Indicate?
Weather radars use scanning strategies to measure moisture and show results in various colors. The color scale shows green color, yellow, purple, and red, which you often see on daily weather forecasts and a radar screen.
They usually refer to the intensity of the precipitation. Most cooler colors like blue tones indicate light precipitation or raindrops while red and purple show heavier precipitation. Yellow hangs around the middle.
Are Weather Radars Dangerous?
No, weather radars are not dangerous because the beam is angled up into the sky and always moving. They are merely tools that observe current weather conditions by detecting the presence and directions of objects.
1960s radar technology was helpful in navigation, national defense, and aviation from a radar station. It poses no hazards to the public as long as the frequencies are adequate. Researchers also have no evidence that exposure to radar sites causes health risks.
The International Commission on Non-Ionizing Radiation Protection has developed standards that regulate radar. The organization, which WHO recognizes, utilizes risk assessments to produce guidelines on radar use.
The radiofrequency levels from radars are at least 1,000 times below the limits when they are close to the general public. There are also engineering and administrative controls for alarms, warning signs, interlocks, and electronic means.
Weather radars have come a long way in providing a comprehensive forecast program, and they’re here to stay! They are a necessary addition to weather stations and traditional instruments for weather detection.
Meteorologists are continuously finding ways to revolutionize the doppler radar, such as through phased-array radar. The ever-evolving radar might even have new applications in the future.
What do you think will the weather radar be like in the next decade? Looking for more info like this? Have a look at our guide to the best weather stations.