CYGNSS Level 3 Climate Data Record Version 1.0
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DOI10.5067/CYGNS-L3C10
Short NameCYGNSS_L3_CDR_V1.0
DescriptionThis dataset contains the Version 1.0 CYGNSS Level 3 Climate Data Record which provides the average wind speed and mean square slope (MSS) on a 0.2x0.2 degree latitude by longitude equirectangular grid obtained from the Delay Doppler Mapping Instrument aboard the CYGNSS satellite constellation. The Level 2 Delay Doppler Map (DDM) data are used in the direct processing of the average wind speed and MSS data that are binned on the Level 3 grid. 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. A single netCDF-4 data file is produced for each day of operation with an approximate 6 day latency. The reported sample locations are determined by the specular points corresponding to the Delay Doppler Maps (DDMs). The Version 1.0 CDR represents the first climate-quality release and is a collection of reanalysis products derived from the SDR v2.1 Level 1 data. Calibration accuracy and long term stability are improved relative to the SDR v2.1 using a new trackwise correction algorithm which constrains the average value of the L1 data using MERRA-2 reanalysis wind speeds. Details of the algorithm are provided in the Trackwise Corrected CDR Algorithm Theoretical Basis Document. CDR Level 2 and 3 products (ocean surface wind speed, mean square slope, and latent and sensible heat flux) are generated from the CDR L1 data using the v2.1 SDR data processing algorithms. These products also exhibit improved calibration accuracy and stability over SDR v2.1. Trackwise correction is applied to the two primary CYGNSS L1 science data products the normalized bistatic radar cross section (NBRCS) and the leading edge slope of the Doppler-integrated delay waveform (LES). The correction compensates for variations in the transmit power level of the GPS signals measured by the CYGNSS bistatic radar receivers. The SDR v2.1 L1 algorithm assumes a constant GPS transmit power and variations in it can be misinterpreted as variations in the L1 data and in subsequent L2 science data products derived from them. The GPS constellation consists of several different satellite models (a.k.a. block types) and the level of transmit power variation differs between them. The more recent Block IIF models (which account for ~37% of the GPS constellation) have significantly larger variations than the older models and, for this reason, they have been screened out and not used to produce SDR v2.1 L2 or L3 science data products. Trackwise correction eliminates the need for this screening so CDR L2 and L3 data products now include Block IIF samples. It should be noted that the trackwise correction algorithm cannot be successfully applied to all SDR v2.1 L1 data so there is also some loss of samples that were present in SDR v2.1. Overall, there is a significant increase in sampling and improvement in spatial coverage with the CDR products.
Version1.0
Dataset TypeOPEN
MeasurementOCEANS > OCEAN WINDS > SURFACE WINDS > OCEAN SURFACE WIND SPEED
Processing Level3
CoverageRegion: Global
Northernmost Latitude: 40 degrees
Southernmost Latitude: 40 degrees
Westernmost Longitude: 0 degrees
Easternmost Longitude: 360 degrees
Time Span: 2017-Mar-18 to Present
Granule Time Span: 2017-Mar-18 to 2020-Apr-30
ResolutionSpatial Resolution: 0.2 degrees (Latitude) x 0.2 degrees (Longitude)
Temporal Resolution: Daily
ProjectionType:
Detail:
Ellipsoid: WGS 84
Latency720 hours
Platform/Sensor
CYGNSS
Platform
Name: Cyclone Global Navigation Satellite System (CYGNSS)
Orbit Period: 94 minutes
Inclination Angle: 35 degrees
Ascending Node: 1970-Jan-01 00:00:00
/
DDMI
SENSOR
Name: Delay Doppler Mapping Instrument (DDMI)
Swath Width: 25 km
Description: Delay Doppler Mapping Instrument (DDMI)

ProjectCyclone Global Navigation Satellite System (CYGNSS)
Data ProviderCreator: CYGNSS
Release Place: PO.DAAC
Release Date: 2020-May-22
Resource: http://clasp-research.engin.umich.edu/missions/cygnss/
Keyword(s)cygnss, ddm, ddmi, doppler, delay doppler, delay, specular point, wind, winds, wind speed, cdr, climate data record, climate, version 1.0, v1.0
Persistent IDPODAAC-CYGNS-L3C10
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
User's Guide
Level 3 Data Dictionaryhttps://podaac-tools.jpl.nasa.gov/drive/files/allData/cygnss/L3/docs/148-0390-1_Level_3_CDR_netCDF_Data_Dictionary.xlsx
Look-up table to define the Level 3 data variables
NASA CYGNSS Handbookhttp://clasp-research.engin.umich.edu/missions/cygnss/reference/cygnss-mission/CYGNSS_Handbook_April2016.pdf
Deriving Surface Winds from Tropical Cyclones
Project Materials
CYGNSS Algorithm Theoretical Basis Document Level 3 Gridded Wind Speedhttp://clasp-research.engin.umich.edu/missions/cygnss/reference/148-0319%20ATBD%20L3%20Gridded%20Wind%20Speed_Rev1_Aug2018_release.pdf
Level 3 Gridded Wind Speed Algorithm Theoretical Basis Document, C. Ruf, CYGNSS Project Document 148-0319, Rev 1, 20 Aug. 2018.
CYGNSS Mission Pagehttps://podaac.jpl.nasa.gov/CYGNSS
CYGNSS Mission Page at University of Michigan
CYGNSS Mission Pagehttp://clasp-research.engin.umich.edu/missions/cygnss/
CYGNSS Mission Page at University of Michigan
CYGNSS ATBD Level 1 & 2 Trackwise Corrected Climate Datahttps://podaac-tools.jpl.nasa.gov/drive/files/allData/cygnss/L3/docs/148-0389-1_ATBD_Trackwise_Corrected_CDR.pdf
Algorithm Theoretical Basis Document (ATBD) for the CYGNSS Climate Data Record (CDR)
Journal References
Ruf et al. 2015 (BAMS)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.
In-Orbit Performance of the Constellation of CYGNSS Hurricane Satelliteshttps://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.
Known Issues
Spacecraft Attitude Tableshttps://podaac-tools.jpl.nasa.gov/drive/files/allData/cygnss/L1/docs/att_tables/
Updated Monthly
Citation CYGNSS. 2020. CYGNSS Level 3 Climate Data Record Version 1.0. Ver. 1.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/CYGNS-L3C10.

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For more information see Data Citations and Acknowledgments.

Journal Reference Ruf, C.S., C. Chew, T. Lang, M.G. Morris, K. Nave, A. Ridley, R. Balasubramaniam, 'A New Paradigm in Earth Environmental Monitoring with the CYGNSS Small Satellite Constellation', Scientific Reports, doi: 10.1038/s41598-018-27127-4, 2018.