CYGNSS Level 2 Science Data Record Version 2.1
DOI10.5067/CYGNS-L2X21
Short NameCYGNSS_L2_V2.1
DescriptionThis dataset contains the Version 2.1 CYGNSS Level 2 Science Data Record which provides the time-tagged and geolocated average wind speed (m/s) and mean square slope (MSS) with 25x25 kilometer resolution from the Delay Doppler Mapping Instrument aboard the CYGNSS satellite constellation. This version supersedes Version 2.0. The reported sample locations are determined by the specular points corresponding to the Delay Doppler Maps (DDMs). A subset of DDM data used in the direct processing of the average wind speed and MSS is co-located inside of the Level 2 data files. Only one netCDF data file is produced each day (each file containing data from up to 8 unique CYGNSS spacecraft) with a latency of approximately 6 days (or better) from the last recorded measurement time. The Version 2.1 release represents the second science-quality release. Here is a summary of improvements that reflect the quality of the Version 2.1 data release: 1) revised Geophysical Model Functions (GMFs) for both Fully Developed Seas (FDS) and Young Seas with Limited Fetch conditions, to be consistent with the calibration changes made to the v2.1 Level 1 science data products.; 2) Revised covariance matrix between DDMA and LES versions of the FDS wind speed retrieval, used by the minimum variance estimator, resulting from changes made to the v2.1 Level 1 science data products; 3) Revised debiasing algorithm coefficients used by the FDS L2 retrieval algorithm, resulting from changes made to the v2.1 Level 2 science data products; 4) revised quality control (Q/C) flags related to the required level of consistency between DDMA and LES versions of the FDS wind speed retrieval (the errors in the two retrievals are now less correlated so larger discrepancies are allowed; if either retrieval is not available, the sample receives a fatal Q/C flag); 5) new Q/C flag related to the block type of the GPS satellite which provided the transmitted signal. Samples using block II-F signals receive a fatal Q/C flag due to the higher level of uncertainty in their radiated power; 6) revised wind speed uncertainty values as a function of RCG and wind speed, plus a new dependence of the uncertainty on GPS block type to reflect the higher uncertainty in GPS radiated power for block II-F satellites.
Version2.1
Dataset TypeACTIVE
MeasurementSPECTRAL/ENGINEERING > RADAR > RADAR CROSS-SECTION
OCEANS > OCEAN WINDS > SURFACE WINDS
Processing Level2
CoverageRegion: GLOBAL
North Bounding Coordinate: 40 degrees
South Bounding Coordinate: -40 degrees
West Bounding Coordinate: -180 degrees
East Bounding Coordinate: 180 degrees
Time Span: 2017-Mar-18 to Present
Granule Time Span: 2017-Mar-18 to 2021-Jul-26
ResolutionSpatial Resolution: 25 km (Along) x 25 km (Across)
ProjectionProjection Type: Satellite native along-track
Projection Detail: Geolocation information included for each pixel
Ellipsoid: WGS 84
Swath Width25 km
Platform/Sensor
CYGNSS
Platform
Name: Cyclone Global Navigation Satellite System (CYGNSS)
Orbit Period: 94.0 minutes
Inclination Angle: 35.0 degrees
/
DDMI
SENSOR
Name: Delay Doppler Mapping Instrument (DDMI)
Swath Width: 25.0 kilometers
Description: Spacecraft angular distance from orbital plane relative to the Equator.

ProjectCyclone Global Navigation Satellite System (CYGNSS)
Data ProviderPublisher: PO.DAAC
Creator: CYGNSS
Release Place: PO.DAAC
Release Date: 2018-Sep-21
Resource: http://clasp-research.engin.umich.edu/missions/cygnss/

Keyword(s)cygnss, ddm, ddmi, doppler, delay doppler, delay, specular point, wind, winds, wind speed, version 2.1, v2.1
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
PUBLICATIONS
  • https://doi.org/10.1175/BAMS-D-14-00218.1
    Ruf, C., R. Atlas, P. Chang, M. Clarizia, J. Garrison, S. Gleason, S. Katzberg, Z. Jelenak, J. Johnson, S. Majumdar, A. O'Brien, D. Posselt, A. Ridley, R. Rose, V. Zavorotny (2015). New Ocean Winds Satellite Mission to Probe Hurricanes and Tropical Convection. Bull. Amer. Meteor. Soc., doi:10.1175/BAMS-D-14-00218.1.
  • https://doi.org/10.1109/JSTARS.2018.2833075
    Ruf, C., R. Balasubramaniam, 'Development of the CYGNSS Geophysical Model Function for Wind Speed', IEEE J. Sel. Topics Appl. Earth Obs. Remote Sens., doi: 10.1109/JSTARS.2018.2833075, 2018.
  • https://doi.org/10.1175/JTECH-D-20-0079.1
    Asharaf, S., Waliser, D. E., Posselt, D. J., Ruf, C. S., Zhang, C., & Putra, A. W. (2021). CYGNSS Ocean Surface Wind Validation in the Tropics, Journal of Atmospheric and Oceanic Technology, 38(4), 711-724. https://doi.org/10.1175/JTECH-D-20-0079.1
  • https://doi.org/10.1175/BAMS-D-18-0337.1
    Ruf, C., S. Asharaf, R. Balasubramaniam, S. Gleason, T. Lang, D. McKague, D. Twigg, and D. Waliser. (2019). In-Orbit Performance of the Constellation of CYGNSS Hurricane Satellites. Bull. Amer. Meteor. Soc., 100, 2009 - 2023, https://doi.org/10.1175/BAMS-D-18-0337.1.
  • https://doi.org/10.1109/TGRS.2016.2541343
    Clarizia, M. P., and C. S. Ruf, 'Wind Speed Retrieval Algorithm for the Cyclone Global Navigation Satellite System (CYGNSS) Mission', IEEE Trans Geosci. Remote Sens., doi:10.1109/TGRS.2016.2541343, 2016.
USER'S GUIDE
ANOMALIES
GENERAL DOCUMENTATION
DATA CITATION POLICY
Citation CYGNSS. 2018. CYGNSS Level 2 Science Data Record Version 2.1. Ver. 2.1. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/CYGNS-L2X21

Download Citation
RIS XML JSON-LD

For more information see Data Citations and Acknowledgments.

Journal Reference Asharaf, S., Waliser, D. E., Posselt, D. J., Ruf, C. S., Zhang, C., & Putra, A. W. (2021). CYGNSS Ocean Surface Wind Validation in the Tropics, Journal of Atmospheric and Oceanic Technology, 38(4), 711-724. https://doi.org/10.1175/JTECH-D-20-0079.1

.

VersionDatasetVersion DateStatus
3.0CYGNSS Level 2 Science Data Record Version 3.02020-09-22ACTIVE1600796085416
2.1CYGNSS Level 2 Science Data Record Version 2.12018-05-14ACTIVE1526337518292
2.0CYGNSS Level 2 Science Data Record Version 2.02017-10-27RETIRED1509074651180
1.1CYGNSS Level 2 Science Data Record Version 1.12017-06-09RETIRED1496969012015
1.0CYGNSS Level 2 Science Data Record Version 1.02016-05-12RETIRED1463079879661