What Are The Different Modes Used By NEXRAD Doppler Radar?
While conventional radar displays reflectivity data gathered at only one elevation angle from one 360° sweep, NEXRAD Doppler radar, also known as WSR-88D (Weather Surveillance Radar – 1988 Doppler), is operated in one of three possible volume scan strategies. Clear Air Mode A NEXRAD Doppler radar will typically operate in the clear air mode when little or no precipitation is being detected within the effective range of the radar for reflectivity data (460 km or 286 mi.). In clear air mode, the radar completes either seven or eight 360° sweeps at five unique elevation angles between .5° and 4.5° above the local horizon, comprising a “volume scan.” NEXRAD data is updated every 10 minutes for all products except the three layers of Layer Composite Reflectivity, Vertically Integrated Liquid and Echo Tops products, which are not available when the radar is in clear air mode. Precipitation Mode When the radar detects a significant amount of precipitation, it is then operated in the precipita
