CYGNSS Level 3 Climate Data Record Version 1.0
(CYGNSS_L3_CDR_V1.0)| Version | 1.0 |
| Processing Level | 3 |
| Start/Stop Date | 2017-Mar-18 to 2021-Feb-28 |
| Short Name | CYGNSS_L3_CDR_V1.0 |
| Description | This 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 2 month 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. |
| DOI | 10.5067/CYGNS-L3C10 |
| Measurement | OCEANS > OCEAN WINDS > SURFACE WINDS |
| 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. |
| Project | Cyclone Global Navigation Satellite System (CYGNSS) |
| Data Provider | Publisher: PO.DAAC Creator: CYGNSS Release Place: PO.DAAC Release Date: 2020-May-22 Resource: https://cygnss.engin.umich.edu/ |
| Format | netCDF-4 |
| 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 |
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
Resolution Spatial Resolution: 0.2 Decimal Degrees x 0.2 Decimal Degrees Temporal Resolution: Hourly - < Daily Coverage Region: 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 2021-Feb-28 Granule Time Span: 2017-Mar-18 to 2021-Feb-28 Projection Projection Type: Cylindrical Lat-Lon Projection Detail: Geolocation information included for each pixel Ellipsoid: WGS 84 |
| DIRECT ACCESS | |
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| OPENDAP DATA | |
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| DIRECT S3-ACCESS | |
| Available for access in-region with AWS Cloud | |
Region | |
| us-west-2 | |
| podaac-ops-cumulus-protected/CYGNSS_L3_CDR_V1.0/ | |
| podaac-ops-cumulus-public/CYGNSS_L3_CDR_V1.0/ | |
AWS S3 Credentials | |
| Get AWS S3 Credentials | Documentation | |
| Name | Long Name | Unit |
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| epoch_time | Time Centering of Data Based on Epoch Reference | hours since 2017-03-18 00:30:00.000000000 |
| lat | Latitude | degrees_north |
| lon | Longitude | degrees_east |
| mean_square_slope | Mean square slope | 1 |
| mean_square_slope_uncertainty | Mean square slope uncertainty | 1 |
| merra2_wind_speed | MERRA-2 reference wind speed | m s-1 |
| num_merra2_wind_speed_samples | Number of MERRA-2 wind speed samples | 1 |
| num_mss_samples | Number of mean square slope samples | 1 |
| num_wind_speed_samples | Number of wind speed samples | 1 |
| num_yslf_wind_speed_samples | Number of young sea limited fetch wind speed samples | 1 |
| time | Reference time of file | hours since 2017-03-18 00:30:00.000000000 |
| wind_speed | Wind speed | m s-1 |
| wind_speed_uncertainty | Wind speed uncertainty | m s-1 |
| yslf_wind_speed | Young sea limited fetch wind speed | m s-1 |
| yslf_wind_speed_uncertainty | Young sea limited fetch wind speed uncertainty | m s-1 |
| DATA RECIPE | |
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| USER'S GUIDE | |
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| ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD) | |
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| ANOMALIES | |
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| DATA CITATION POLICY | |
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| GENERAL DOCUMENTATION | |
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. 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
For more information see Data Citations and Acknowledgments.
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| Journal Reference | Ruf, C. S., Chew, C., Lang, T., Morris, M.G., Nave, K., Ridley, A., Balasubramaniam, R. . 2018. A New Paradigm in Earth Environmental Monitoring with the CYGNSS Small Satellite Constellation, Scientific Reports, 8, 8782. https://doi.org//10.1038/s41598-018-27127-4 |
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| Version | Dataset | Version Date | Status | |
|---|---|---|---|---|
| 3.2 | CYGNSS Level 3 Climate Data Record Version 3.2 | 2024-04-10 | ACTIVE | 2024-04-10T19:27:00.000Z |
| 1.2 | CYGNSS Level 3 Climate Data Record Version 1.2 | 2022-05-19 | ACTIVE | 2022-05-19T21:12:00.000Z |
| 1.1 | CYGNSS Level 3 Climate Data Record Version 1.1 | 2022-04-11 | ACTIVE | 2022-04-11T15:44:00.000Z |
| 1.0 | CYGNSS Level 3 Climate Data Record Version 1.0 | 2021-08-26 | COMPLETE | 2021-08-26T14:45:00.000Z |