CYGNSS Level 1 Climate Data Record Version 1.1

Processing Level1
Start/Stop Date2018-Aug-01 to Present
Short NameCYGNSS_L1_CDR_V1.1
DescriptionThis Level 1 (L1) dataset contains the Version 1.1 Climate Data Record (CDR) of the geo-located Delay Doppler Maps (DDMs) calibrated into Power Received (Watts) and Bistatic Radar Cross Section (BRCS) expressed in units of m2 from the Delay Doppler Mapping Instrument aboard the CYGNSS satellite constellation. Other useful scientific and engineering measurement parameters include the DDM of Normalized Bistatic Radar Cross Section (NBRCS), the Delay Doppler Map Average (DDMA) of the NBRCS near the specular reflection point, and the Leading Edge Slope (LES) of the integrated delay waveform. The L1 dataset contains a number of other engineering and science measurement parameters, including sets of quality flags/indicators, error estimates, and bias estimates as well as a variety of orbital, spacecraft/sensor health, timekeeping, and geolocation parameters. At most, 8 netCDF data files (each file corresponding to a unique spacecraft in the CYGNSS constellation) are provided each day; under nominal conditions, there are typically 6-8 spacecraft retrieving data each day, but this can be maximized to 8 spacecraft under special circumstances in which higher than normal retrieval frequency is needed (i.e., during tropical storms and or hurricanes). Latency is approximately 1 month, depending on the availability of the MERRA wind speed reanalysis. The Version 1.1 CDR is a collection of reanalysis products derived from the SDR v3.0 Level 1 data ( ). Calibration accuracy and long term stability are improved relative to SDR v3.0 using the same trackwise correction algorithm as was used by CDR v1.0 ( ), which was derived from SDR v2.1 Level 1 data ( ). Details of the algorithm are provided in the Trackwise Corrected CDR Algorithm Theoretical Basis Document. Trackwise correction is applied to the two primary CYGNSS L1 science data products, the normalized bistatic radar cross section (NBRCS) and the LES. The correction compensates for small errors in the Level 1 calibration, due e.g. to uncertainties in the GPS transmitting antenna gain patterns and the CYGNSS receiving antenna gain patterns. It should be noted that the trackwise correction algorithm cannot be successfully applied to all v3.0 SDR L1 data, so there is also some loss of samples that were present in v3.0.
Swath Width25 km
Name: Cyclone Global Navigation Satellite System (CYGNSS)
Orbit Period: 94.0 minutes
Inclination Angle: 35.0 degrees
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: 2021-Feb-05

Keyword(s)cygnss, ddm, ddmi, ddma, doppler, delay doppler, delay, specular point, waveform, les, leading edge slope, bistatic, bi-static, radar, brcs, sigma0, sigma-0, sigma naught, sigma-naught, nbrcs, wind, winds, wind speed, cdr, version 1.1, v1.1
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Spatial Resolution: 25000 Meters x 25000 Meters
Temporal Resolution: Hourly - < Daily
Region: GLOBAL
North Bounding Coordinate: 40 degrees
South Bounding Coordinate: -40 degrees
West Bounding Coordinate: -180 degrees
East Bounding Coordinate: 180 degrees
Time Span: 2018-Aug-01 to Present
Granule Time Span: 2018-Aug-01 to 2022-Apr-30
Swath Width: 25 km
Projection Type: Satellite native along-track
Projection Detail: Geolocation information included for each pixel
Ellipsoid: WGS 84
    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.
    Gleason, S., C. Ruf, M. P. Clarizia, A. O'Brien, 'Calibration and Unwrapping of the Normalized Scattering Cross Section for the Cyclone Global Navigation Satellite System (CYGNSS)', IEEE Trans. Geosci. Remote Sens., doi:10.1109/TGRS.2015.2502245, 2016.
Citation is critically important for dataset documentation and discovery. Please cite the data as follows, and cite the reference papers when it is appropriate.
Citation CYGNSS. 2021. CYGNSS Level 1 Climate Data Record Version 1.1. Ver. 1.1. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at

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For more information see Data Citations and Acknowledgments.

Journal Reference Gleason, S., C. S. Ruf, A. O'Brien, D. S. McKague. 2018. The CYGNSS Level 1 Calibration Algorithm and Error Analysis Based On On-Orbit Measurements, IEEE J. Sel. Topics Appl. Earth Obs. Remote Sens, 12, 1. 10.1109/JSTARS.2018.2832981

VersionDatasetVersion DateStatus
1.2CYGNSS Level 1 Climate Data Record Version 1.22022-05-19ACTIVE2022-05-19T21:15:00.000Z
1.2CYGNSS Level 1 Climate Data Record Version 3.22024-04-10ACTIVE2024-04-10T19:40:00.000Z
1.1CYGNSS Level 1 Climate Data Record Version 1.12022-04-11ACTIVE2022-04-11T16:51:00.000Z
1.0CYGNSS Level 1 Climate Data Record Version 1.02021-04-22COMPLETE2021-04-22T15:18:00.000Z