NOAA Next Generation Radar (NEXRAD) Level 2 Base Data

Weather Radar (Level II)

browse graphicWSR-88D RADAR
This dataset consists of Level II weather radar data collected from Next-Generation Radar (NEXRAD) stations located in the contiguous United States, Alaska, Hawaii, U.S. territories and at military base sites. NEXRAD is a network of 160 high-resolution Doppler weather radars operated by the NOAA National Weather Service (NWS), the Federal Aviation Administration (FAA), and the U.S. Air Force (USAF). Doppler radars detect atmospheric precipitation and winds, which allow scientists to track and anticipate weather events, such as rain, ice pellets, snow, hail, and tornadoes, as well as some non-weather objects like birds and insects. NEXRAD stations use the Weather Surveillance Radar - 1988, Doppler (WSR-88D) system. This is a 10 cm wavelength (S-Band) radar that operates at a frequency between 2,700 and 3,000 MHz. The radar system operates in two basic modes: a slow-scanning Clear Air Mode (Mode B) for analyzing air movements when there is little or no precipitation activity in the area, and a Precipitation Mode (Mode A) with a faster scan for tracking active weather. The two modes employ nine Volume Coverage Patterns (VCPs) to adequately sample the atmosphere based on weather conditions. A VCP is a series of 360 degree sweeps of the antenna at pre-determined elevation angles and pulse repetition frequencies completed in a specified period of time. The radar scan times 4.5, 5, 6 or 10 minutes depending on the selected VCP. The NEXRAD products are divided into multiple data processing levels. The lower Level II data contain the three meteorological base data quantities at original resolution: reflectivity, mean radial velocity, and spectrum width. With the advent of dual polarization beginning in 2011, additional base products of differential reflectivity, correlation coefficient and differential phase are available. Level II data are recorded at all NWS and most USAF and FAA WSR-88D sites. From the Level II quantities, computer processing generates numerous meteorological analysis Level 3 products. NEXRAD data are acquired by the NOAA National Centers for Environmental Information (NCEI) for archiving and dissemination to users. Data coverage varies by station and ranges from June 1991 to 1 day from present. Most stations began observing in the mid-1990s, and most period of records are continuous.
  • Cite as: NOAA National Weather Service (NWS) Radar Operations Center (1991): NOAA Next Generation Radar (NEXRAD) Level 2 Base Data. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.7289/V5W9574V [access date].
  • doi:10.7289/V5W9574V
  • NCEI DSI 6500_12
  • NCEI DSI 6500_13
  • NCEI DSI 6500_14
  • NCEI DSI 6500_15
  • gov.noaa.ncdc:C00345
Search Data
  • OCC Environmental Data Commons (search)
    Service to search space and time for NEXRAD level 2 data of interest. This search service will return persistent digital identifiers for accessing data from given NEXRAD stations and date ranges.
  • NCEI Climate Data Online Search Tool (search)
    Search for data and metadata by station ID, location, and date range via a text-based interface.
  • NCEI GIS Map Viewer (search)
    Dynamic GIS mapping application to locate stations and data for selected layers.
  • NCEI NEXRAD Data Inventory Search (search)
    Search for radar data and estimated VCP mode by station ID, location, and date via a text-based interface.
Download Data
Distribution Formats
  • Native Binary
    • File Compression: Unix Zip (.Z), GNU zip (.gz), or Bzip2 compression, and tape archive (.tar) may be applied to data files retrieved from the NCEI archive.
Distributor Customer Engagement Branch
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
1-828-271-4800
ncei.orders@noaa.gov
Dataset Point of Contact Customer Engagement Branch
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
1-828-271-4800
ncei.orders@noaa.gov
Time Period 1991-06-05 to Present
Spatial Bounding Box Coordinates
N: 68.0
S: 11.0
E: -64.0
W: 124.0
Spatial Coverage Map
Dataset Information
General Documentation
Associated Resources
Publication Dates
  • publication: 1991
Data Presentation Form Digital image
Dataset Progress Status Ongoing - data is continually being updated
Data Update Frequency Continual
Supplemental Information
During 2008, the WSR-88D radars were upgraded to produce increased spatial resolution data, called Super Resolution. The earlier (Legacy Resolution) data before 2008 provides radar reflectivity at 1.0 degree azimuthal by 1 km range gate resolution to a range of 460 km, and Doppler velocity and spectrum width at 1.0 degree azimuthal by 250 m range gate resolution to a range of 230 km. The upgraded Super Resolution data provides radar reflectivity at 0.5 degree azimuthal by 250 m range gate resolution to a range of 460 km, and Doppler velocity and spectrum width at 0.5 degree azimuthal by 250 m range gate resolution to a range of 300 km. Super resolution makes a compromise of slightly decreased noise reduction for a large gain in resolution. In 2010, the deployment of the Dual Polarization (Dual Pol) capability to NEXRAD sites began with the first operational Dual Pol radar in May 2011. Dual Pol radar capability adds vertical polarization to the previous horizontal radar waves, in order to more accurately discern the return signal. This allows the radar to better distinguish between types of precipitation (e.g., rain, hail and snow), improves rainfall estimates, improves data retrieval in mountainous terrain, and aids in removal of non-weather artifacts.
Purpose Level-2 NEXRAD data include three meteorological base data quantities: reflectivity, mean radial velocity, and spectrum width. With the advent of dual polarization beginning in 2011, additional base products of differential reflectivity, correlation coefficient and differential phase are available.
Dataset Citation
  • Cite as: NOAA National Weather Service (NWS) Radar Operations Center (1991): NOAA Next Generation Radar (NEXRAD) Level 2 Base Data. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.7289/V5W9574V [access date].
Cited Authors
  • DOC/NOAA/NWS/ROC > Radar Operations Center, National Weather Service, NOAA, U.S. Department of Commerce
Originators
  • DOC/NOAA/NWS/ROC > Radar Operations Center, National Weather Service, NOAA, U.S. Department of Commerce
Publishers
  • NOAA National Centers for Environmental Information
  • DOC/NOAA/NESDIS/NCDC > National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce
Theme keywords Global Change Master Directory (GCMD) Science Keywords
  • Earth Science > Spectral/Engineering > Radar > Doppler Velocity
  • Earth Science > Spectral/Engineering > Radar > Radar Reflectivity
  • Earth Science > Spectral/Engineering > Radar > Spectrum Width
  • Earth Science > Spectral/Engineering > Sensor Characteristics > Viewing Geometry
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NWS/ROC > Radar Operations Center, National Weather Service, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCDC > National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce
Platform keywords Global Change Master Directory (GCMD) Platform Keywords
  • In Situ Land-based Platforms > Weather Stations/Networks > Weather Stations
Instrument keywords Global Change Master Directory (GCMD) Instrument Keywords
  • Earth Remote Sensing Instruments > Active Remote Sensing > Profilers/Sounders > Radar Sounders > NEXRAD > NEXt Generation RADar
  • Earth Remote Sensing Instruments > Active Remote Sensing > Profilers/Sounders > Radar Sounders > Doppler Radar
Place keywords Global Change Master Directory (GCMD) Location Keywords
  • Continent > North America > United States Of America
  • Continent > Asia > Eastern Asia > South Korea
  • Geographic Region > Mid-Latitude
  • Geographic Region > Northern Hemisphere
  • Ocean > Atlantic Ocean > North Atlantic Ocean > Azores
  • Ocean > Atlantic Ocean > North Atlantic Ocean > Caribbean Sea > Puerto Rico
  • Ocean > Atlantic Ocean > North Atlantic Ocean > Gulf Of Mexico
  • Ocean > Pacific Ocean > Central Pacific Ocean > Guam
  • Ocean > Pacific Ocean > Central Pacific Ocean > Hawaiian Islands
  • Ocean > Pacific Ocean > Central Pacific Ocean > Kiribati
  • Ocean > Pacific Ocean > North Pacific Ocean > Bering Sea
  • Ocean > Pacific Ocean > North Pacific Ocean > Gulf Of Alaska
  • Ocean > Pacific Ocean > North Pacific Ocean > Okinawa
  • Ocean > Pacific Ocean > Western Pacific Ocean > East China Sea
  • Ocean > Pacific Ocean > Western Pacific Ocean > Yellow Sea
Project keywords Global Change Master Directory (GCMD) Project Keywords
  • NOAA OneStop Project
Keyword Thesaurus Title
  • NOAA Big Data Project (BDP)
Stratum keywords Global Change Master Directory (GCMD) Location Keywords
  • Vertical Location > Boundary Layer
  • Vertical Location > Land Surface
  • Vertical Location > Troposphere
Use Constraints
  • Cite as: NOAA National Weather Service (NWS) Radar Operations Center (1991): NOAA Next Generation Radar (NEXRAD) Level 2 Base Data. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.7289/V5W9574V [access date].
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Access Constraints
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Fees
  • In most cases, electronic downloads of the data are free, however fees may apply for data certifications, copies of analog materials, and data distribution on physical media.
Lineage information for: dataset
Lineage Statement NEXRAD Level 2 data were collected by the NOAA National Weather Service (NWS) and are archived at the NOAA National Centers for Environmental Information (NCEI).
Processing Steps
  • Radar signals are processed to Level 2 data at radar sites.
Lineage information for: repository
Processing Steps
  • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Acquisition Information (collection)
Instrument
  • NEXRAD > NEXt Generation RADar
Platform
  • National Weather Service
Operation
  • NEXRAD > NEXt Generation Weather RADar
Last Modified: 2018-11-05
For questions about the information on this page, please email: ncei.orders@noaa.gov