CYGNSS Level 2 Science Data Record Version 3.2
(CYGNSS_L2_V3.2)| Version | 3.2 |
| Processing Level | 2 |
| Start/Stop Date | 2018-Aug-01 to Present |
| Short Name | CYGNSS_L2_V3.2 |
| Description | This dataset contains the version 3.2 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 3.1: https://doi.org/10.5067/CYGNS-L2X31. 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 L2 Geophysical Model Function (GMF) that maps L1 observables to ocean surface wind speed and the Significant Wave Height (SWH) second order correction to the wind speed retrievals were rederived to be consistent with the v3.2 L1 calibration. The method used for deriving the GMF and SWH correction is the same as for v3.1. An additional swell wave correction has been added to better account for the long wave dependence at low wind speeds. The FDS and YSLF retrieval algorithms are otherwise the same as v3.1. The v3.2 L2 YSLF wind speed is now designated as an intermediate product and should not be used ‘as is’. Additional quality control filters have been added to the Level 3 gridded product derived from the L2 YSLF wind speed to detect and remove outlier L2 samples, and use of the L3 product is recommended. The CYGNSS is a NASA Earth System Science Pathfinder Mission that is intended to collect the first frequent space‐based measurements of surface wind speeds in the inner core of tropical cyclones. Made up of a constellation of eight micro-satellites, the observatories provide nearly gap-free Earth coverage using an orbital inclination of approximately 35° from the equator, with a mean (i.e., average) revisit time of seven hours and a median revisit time of three hours. This inclination allows CYGNSS to measure ocean surface winds between approximately 38° N and 38° S latitude. This range includes the critical latitude band for tropical cyclone formation and movement. |
| DOI | 10.5067/CYGNS-L2X32 |
| Measurement | OCEANS > OCEAN WINDS > SURFACE WINDS 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: 2024-Mar-05 Resource: https://cygnss.engin.umich.edu/ |
| Format | netCDF-4 |
| Keyword(s) | cygnss, ddm, ddmi, doppler, delay doppler, delay, specular point, wind, winds, wind speed, version 3.2, v3.2 |
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
Resolution Spatial Resolution: 25 Kilometers x 25 Kilometers Temporal Resolution: Hourly - < Daily Coverage 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 Projection Projection Type: Satellite native along-track Ellipsoid: WGS 84 |
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| us-west-2 | |
| podaac-ops-cumulus-protected/CYGNSS_L2_V3.1/ | |
| podaac-ops-cumulus-public/CYGNSS_L2_V3.1/ | |
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| Name | Long Name | Unit |
|---|---|---|
| antenna | Receive antenna | 1 |
| averaged_l1 | Maximum number of time-averaged L1-samples occuring in the same second | 1 |
| azimuth_angle | Azimuth angle | degree |
| bit_ratio_lo_hi_port | Port low/high bit counter ratio | 1 |
| bit_ratio_lo_hi_starboard | Starboard low/high bit counter ratio | 1 |
| bit_ratio_lo_hi_zenith | Zenith low/high bit counter ratio | 1 |
| commanded_sc_roll | Commanded spacecraft attitude roll angle | radian |
| ddm | Maximum number of time-averaged DDMs | 1 |
| ddm_averaged_l1_utilized_flag | DDM Average L1 utilized flags | 1 |
| ddm_channel | Level 1 DDM reflectometry channels | 1 |
| ddm_les | DDM leading edge slope observables | 1 |
| ddm_nbrcs | DDM normalized bistatic radar cross section observables | 1 |
| ddm_num_averaged_l1 | Number of valid L1 samples averaged | 1 |
| ddm_obs_utilized_flag | DDM-utilized flags | 1 |
| ddm_sample_index | Level 1 netCDF sample indices | 1 |
| ddm_source | Level 0 data source | 1 |
| fds_les_wind_speed | Fully Developed Seas retrieval of wind speed from LES | m s-1 |
| fds_nbrcs_wind_speed | Fully Developed Sea retrieval of wind speed from NBRCS | m s-1 |
| fds_sample_flags | Sample status flags for Fully Developed Seas wind speed retreval | |
| fresnel_coeff | Fresnel power reflection coefficient | 1 |
| incidence_angle | Incidence angle | degree |
| lat | Latitude | degrees_north |
| les_mean | LES mean | 1 |
| lon | Longitude | degrees_east |
| mean_square_slope | Mean square slope | 1 |
| mean_square_slope_uncertainty | Mean square slope uncertainty | 1 |
| mss_sample_flags | Sample status flags for the Mean SquareSlope retreval | |
| nbrcs_mean | NBRCS mean | 1 |
| num_ddms_utilized | Number of DDM utilized | 1 |
| port_gain_setting | The Nadir-Port Gain Setting | dB |
| preliminary_yslf_nbrcs_high_wind_speed | Preliminary Young Seas/Limited Fetch retrieval of wind speed from NBRCS | m s-1 |
| preliminary_yslf_wind_speed | Preliminary YSLF wind speed with SWH correction applied | m s-1 |
| preliminary_yslf_wind_speed_uncertainty | Preliminary uncertainty in YSLF wind speed | m s-1 |
| prn_code | GPS PRN code | 1 |
| range_corr_gain | Range corrected gain | 1e-27 dBi meter-4 |
| sample | Sample index | 1 |
| sample_flags | General status flags for the sample | |
| sample_time | Sample time | seconds since 2018-08-11 00:00:00.999261459 |
| sc_alt | Spacecraft altitude | meter |
| sc_lat | Subsatellite point latitude | degrees_north |
| sc_lon | Subsatellite point longitude | degrees_east |
| sc_roll | Spacecraft attitude roll angle | radian |
| spacecraft_id | CCSDS spacecraft identifier | 1 |
| spacecraft_num | CYGNSS spacecraft number | 1 |
| starboard_gain_setting | The Nadir-Starboard Gain Setting | dB |
| sum_neg_brcs_value_used_for_nbrcs_flags | Sum of negative BRCS values used for NBRCS flags | 1 |
| sv_num | GPS space vehicle number | 1 |
| swh | Significant height of combined wind waves and swell | m |
| swh_corr_method | Method of significant wave height correction | 1 |
| swh_swell_sum | Sum of the swell components of the significant wave height | m |
| wind_speed | Retrieved wind speed using Minimum Variance estimator applied to Fully Developed Seas retrievals from NBRCS and LES | m s-1 |
| wind_speed_bias | Bias in MV FDS wind speed | m s-1 |
| wind_speed_uncertainty | Uncertainty in MV FDS wind speed | m s-1 |
| yslf_sample_flags | Sample status flags for Young Seas/Limited Fetch wind speed retreval |
| DATA RECIPE | |
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| GENERAL DOCUMENTATION | |
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| DATA CITATION POLICY | |
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| ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD) | |
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| DATA PRODUCT SPECIFICATION | |
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| PUBLICATIONS | |
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| USER'S GUIDE | |
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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. 2024. CYGNSS Level 2 Science Data Record Version 3.1. Ver. 3.1. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/CYGNS-L2X32
For more information see Data Citations and Acknowledgments.
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| Journal Reference | Ruf, C., R. Balasubramaniam. 2018. Development of the CYGNSS Geophysical Model Function for Wind Speed, IEEE J. Sel. Topics Appl. Earth Obs. Remote Sens.. https://doi.org//10.1109/JSTARS.2018.2833075 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.. https://doi.org//10.1175/BAMS-D-14-00218.1 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.. https://doi.org//10.1175/BAMS-D-18-0337.1 Clarizia, M. P., and C. S. Ruf. 2016. Wind Speed Retrieval Algorithm for the Cyclone Global Navigation Satellite System (CYGNSS) Mission, IEEE Trans Geosci. Remote Sens.. https://doi.org//10.1109/TGRS.2016.2541343 Gleason, S., M. M. Al-Khaldi, C. Ruf, D. S. McKague, T. Wang, A. Russel. 2021. Characterizing and Mitigating Digital Sampling Effects on the CYGNSS Level 1 Calibration, IEEE Trans. Geosci. Remote Sens.. https://doi.org//10.1109/TGRS.2021.3120026 Pascual, D., M. P. Clarizia, C. S. Ruf. 2021. Improved CYGNSS Wind Speed Retrieval Using Significant Wave Height Correction, Remote Sensing. https://doi.org//10.3390/rs13214313 Wang, T., Ruf, C. S., Gleason, S., O’Brien, A. J., McKague, D. S., Block, B. P., Russel, A.. 2021. Dynamic Calibration of GPS Effective Isotropic Radiated Power for GNSS-Reflectometry Earth Remote Sensing, IEEE Trans. Geosci. Remote Sens. . https://doi.org//10.1109/TGRS.2021.3070238 |
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