Products from elevation angles at or below 3.5 degrees are available, and select sites may also scan at an additional low elevation angle, as low as -0.2 degrees. The same as N*R products defined above, except data values are actual reflectivity values instead of categories, data extends to further range, and additional elevations are available. Digital Base Reflectivity (NXQ, NYQ, NZQ, N0Q, NAQ, N1Q, NBQ, N2Q, N3Q/94) Sixteen possible data levels are also available. Four low elevation angles are available, with specific elevation angles depending on the scanning mode of the Radar. Scientists use these products to detect precipitation, evaluate storm structure, locate boundaries, and determine hail potential. Product Descriptionsīase Reflectivity (N0R, N1R, N2R, N3R/19 and N0Z/20)Ī display of echo intensity measured in decibels relative to Z (dBZ). Each copy includes state, county, and city background maps. Most 元 products are available as digital images, color hard copy, grayscale hard copy, or acetate overlay copy. Over 75 Level-III (元) products are routinely available from NCEI. A data file consists of a 24-byte volume scan header record followed by numerous 2,432-byte base data and message records. Data are stored in files that typically contain four, five, six, or ten minutes of base data depending on the volume coverage pattern. Additional categories include dual-polarization base data of differential reflectivity, correlation coefficient, and differential phase. Level-II (L2) data are grouped into three meteorological base quantities: reflectivity, mean radial velocity, and spectrum width. Request Offline Data NEXRAD Level-II (Base) Data This dataset is not currently available for direct download from NCEI, but is available by request from the offline archive. An inventory of events is available here. An event summary file with descriptive information is included for each case study. The data files have been aggregated by event and by hour for the archive with a total data volume of approximately 20 TB. The data files are in the native compressed file format as Time Series (TS) Archive. The number of case studies per year ranges from 1 to 33, with an average of approximately 10 per year. The period of record is from 2008 to present with additional data years planned. NEXRAD operational sites and test sites are used. It includes only the Level 1 data that has been used for algorithm development and verification by the ROC and its partners. This dataset contains the Level-I (L1) raw radar event data recorded at Next Generation Radar (NEXRAD) sites and collected by the NOAA National Weather Service (NWS) Radar Operations Center (ROC) for specific radar case studies. Online Store Data Types Level-I Event Data Usually a red dot next to a green dot signifies a tornado, but that did not make sense since this was a beautiful, sunny day.The online store provides access documentation, paper copies of data, and other related products. We saw one green dot (which means the object is moving towards the radar), and one red dot (which means the object is moving away from the radar). (True story: I was volunteering at the National Weather Service one sunny afternoon, and we saw some objects show up on the radar, right around where Interstate 20 is located. This process is called “ remote sensing”. Using this analogy, the hail, rain, bugs, and other atmospheric objects are the “people at the door” and the radio waves are the “knock” – you know something’s there, but you can only create an educated guess as to the object’s true identity. Think of it like this – when someone knocks on a door, you know that a person is at the door (because they’re knocking!), but you don’t know exactly who is at the door (that is, until you open it and let them in!). Remember, though, that radars cannot “see” the difference between objects like hail, rain, and bugs – it’s only receiving reflected energy, not a “snap-shot” or a picture of the object that reflected the energy (this is the product of reflected light waves). (Source: NWS Weather Forecast Office in Peacthree City, Georgia) Radar image showing the amount of reflectivity available during the Atlanta Tornado on March 14, 2008
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