Less than 20 dBZ indicates mist, dust, and other small particles. Values of dBZ vary dramatically based on the size, number, shape, and state (liquid or frozen) of targets. Reflectivity imagery is used to assess the location, areal coverage, intensity, general motion, and evolution of weather features such as discrete thunderstorms, thunderstorm clusters, squall lines, tornados, waterspouts, and hurricanes. Reflectivity, measured in dBZ, is the amount of energy that is backscattered by targets and is related to the precipitation rate (how hard it’s raining) of the storm. Let’s take a look at the two most common types of radar imagery.ĭoppler Weather Radar Imagery – Reflectivity By detecting this change in frequency – the Doppler Shift - the station can determine if the object is moving toward or away from the station, and the speed at which it is moving. (Upgrades over the past few years have improved the system’s ability to discern between dust, insects, raindrops, etc.) While the wavelength of the backscattered pulse doesn’t change as it travels through the atmosphere, its frequency shifts based on its motion relative to the radar station. (Click image for a larger version.)Ī wealth of useful information is derived from the backscattered pulses, such as the target’s direction and distance from the station, its height above the ground, its shape, and other physical characteristics. Figure 3: Base reflectivity image from KBUF (Buffalo, New York) with range rings and radials.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |