The National Severe Storms Laboratory calls this "the most significant enhancement ever made to the nation's radar network since Doppler radar. The only downside to dual polarization technology is caused by the Earth itself. As the radar beam gets farther away from the radar site, it climbs higher off of the ground due to the curvature of the Earth. Arguably the most important feature of weather radar is its use of the Doppler effect, which gives the radar the ability to detect how fast precipitation is moving in a certain direction—in other words, it shows us the wind.
The National Weather Service started putting this to use in the s, allowing us to see damaging wind gusts and tornadoes developing within a thunderstorm. Severe weather coverage on television often uses velocity imagery to help meteorologists and viewers figure out where a tornado is most likely to occur within a severe thunderstorm.
Velocity imagery usually consists of red and green colors; red colors usually indicate wind moving away from the radar site, while green shows wind moving toward the radar site. When the red and green colors are very close together within a thunderstorm, this is called a rotational couplet, and this is where a tornado is most likely happening.
The couplet in the right panel of the radar image above shows the winds swirling around the intense EF-4 tornado that struck Tuscaloosa and Birmingham, Alabama, on April 27, You can also use this technology to spot tornado debris. This serves as an incredible advance notice to confirm tornadoes when it would have been otherwise impossible because of heavy rain or lack of sunlight.
The radar images are also able to show the intensity of the precipitation. Satellites were first put into orbit in the s. Satellites with cameras have been used to get images of the Earth's weather from space. Satellites are especially good at showing cloud cover. Photographs of cloud cover are not the only advantages of satellites.
Special instruments are mounted on the satellites. They can measure the temperature of the Earth's surface. The most useful satellites are ones with orbits adjusted so that the speed of the satellite is the same as the speed of rotation of the Earth. Then the satellite stays in the same place overhead.
The Electromagnetic Spectrum Energy is emitted in various frequencies and wavelengths from large wavelength radio waves to shorter wavelength gamma rays. Radars emit microwave energy, a longer wavelength, highlighted in yellow. How Do Radars Work? The radar transmits a focused pulse of microwave energy yup, just like a microwave oven or a cell phone, but stronger at an object, most likely a cloud. Part of this beam of energy bounces back and is measured by the radar, providing information about the object.
Radar can measure precipitation size, quantity, speed and direction of movement, within about mile radius of its location. Doppler radar is a specific type of radar that uses the Doppler effect to gather velocity data from the particles that are being measured. For example, a Doppler radar transmits a signal that gets reflected off raindrops within a storm. The reflected radar signal is measured by the radar's receiver with a change in frequency.
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