radar application in weather forecast eecs 725 chao jiang 05/01/2015
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Radar Application in Weather ForecastEECS 725Chao Jiang05/01/2015
Radar Application in Weather Forecast• Introduce to Weather Radar
• Typical Weather Radar Specification
• Limitation and Future Development
Weather Radar• Most of the weather radars are monostatic radars.
• Capable of detecting location of precipitation, calculating the motion of rain droplets, and its intensity.
• Usually operates in S-band and C-band.
• X-band weather radar is used only to detect nearby target, and Ka-band is used to research small-particle phenomenon.
• Ground, Airborne, and Spaceborne.
Introduce to WSR-88D Weather Radar• WSR-88D Network (160 Radars), operated by National Weather
Service
• Deployed across the US in the 1990s.
• Was the first radar able to detect particle motions.
• Operates in S-band (Frequency: 3.1 GHz; wavelength: 10.5 cm)
Basic Structure
Dual-polarization
Dual-polarization• Differentiating Rain and Snow.
• Detecting Hail Cores.
• Debris from Significant Tornadoes.
Limitations (Beam Height)• Due to the curvature of the Earth.
Limitations (Beam Height)
Limitations (Attenuation)• Occurs when large objects scatter most of the microwave.
• Makes the storms behind the large object appear weaker
Limitations (PRF constraints)• PRFmin = 2 ΔfD
• PRFmax = c/2Rmax
• Multiple scans at each angle
• Change PRF at the radar depending on the situation
Future development (Phased Array)• Consists of four stationary panels.
• Providing rapid scanning. Able to scan the sky in less than 1 minutes (more than 4 times faster than WSR-88D).
• Making the observation more accurate and reduce false alarms.
Phased Array Radar in Norman, Oklahoma
Reference• http://www.meteor.iastate.edu
• http://www.wdtb.noaa.gov
• http://www.nssl.noaa.gov
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