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 Data Types 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.

Wunderground weather radar