CYGNSS Level 1 Climate Data Record Version 1.1
(CYGNSS_L1_CDR_V1.1)| Version | 1.1 |
| Processing Level | 1 |
| Start/Stop Date | 2018-Aug-01 to Present |
| Short Name | CYGNSS_L1_CDR_V1.1 |
| Description | This 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 (https://doi.org/10.5067/CYGNS-L1X30 ). 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 (https://doi.org/10.5067/CYGNS-L1C10 ), which was derived from SDR v2.1 Level 1 data (https://doi.org/10.5067/CYGNS-L1X21 ). 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. |
| DOI | 10.5067/CYGNS-L1C11 |
| Measurement | SPECTRAL/ENGINEERING > RADAR > RADAR CROSS-SECTION SPECTRAL/ENGINEERING > RADAR > RADAR REFLECTIVITY |
| Swath Width | 25 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. |
| Project | Cyclone Global Navigation Satellite System (CYGNSS) |
| Data Provider | Publisher: PO.DAAC Creator: CYGNSS Release Place: PO.DAAC Release Date: 2021-Feb-05 Resource: https://cygnss.engin.umich.edu/ |
| Format | netCDF-4 |
| 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 |
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
Resolution Spatial Resolution: 25000 Meters x 25000 Meters 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: 2018-Aug-01 to Present Granule Time Span: 2018-Aug-01 to 2022-Apr-30Swath Width: 25 km Projection Projection Type: Satellite native along-track Projection Detail: Geolocation information included for each pixel Ellipsoid: WGS 84 |
| DIRECT ACCESS | |
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| us-west-2 | |
| podaac-ops-cumulus-protected/CYGNSS_L1_CDR_V1.1/ | |
| podaac-ops-cumulus-public/CYGNSS_L1_CDR_V1.1/ | |
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| Name | Long Name | Unit |
|---|---|---|
| add_range_to_sp | Additional range to specular point at DDM sample time | 1 |
| add_range_to_sp_pvt | Additional range to specular point at PVT time | 1 |
| att_timestamp_gps_sec | Attitude timestamp - GPS Seconds | second |
| att_timestamp_gps_week | Attitude timestamp - GPS Week | week |
| att_timestamp_utc | Attitude timestamp - UTC | seconds since 2018-08-02 00:00:00.999261576 |
| bb_nearest | Time to most recent black body reading | second |
| bb_power_temperature_density | Black Body Power Temperature Density | Counts/Kelvin |
| bit_null_offset_port | Port bit count null offset | 1 |
| bit_null_offset_starboard | Starboard bit count null offset | 1 |
| bit_ratio_hi_lo_port | Port high/low bit counter ratio | 1 |
| bit_ratio_hi_lo_starboard | Starboard high/low bit counter ratio | 1 |
| brcs | DDM bin bistatic radar cross section | meter2 |
| brcs_ddm_peak_bin_delay_row | BRCS DDM peak bin delay row | 1 |
| brcs_ddm_peak_bin_dopp_col | BRCS DDM peak bin Doppler column | 1 |
| brcs_ddm_sp_bin_delay_row | BRCS DDM specular point bin delay row | 1 |
| brcs_ddm_sp_bin_dopp_col | BRCS DDM specular point bin Doppler column | 1 |
| commanded_sc_roll | Commanded spacecraft attitude roll angle | radian |
| ddm | DDM reflectometry channel | 1 |
| ddm_ant | DDM Antenna | |
| ddm_brcs_uncert | DDM BRCS uncertainty | 1 |
| ddm_end_time_offset | DDM end time offset | 1e-9 s |
| ddm_les | Leading edge slope | 1 |
| ddm_les_orig | The original observable, before track-wise correction | 1 |
| ddm_nbrcs | Normalized BRCS | 1 |
| ddm_nbrcs_orig | The original observable, before track-wise correction | 1 |
| ddm_noise_floor | DDM noise floor | 1 |
| ddm_snr | DDM signal to noise ratio | dB |
| ddm_source | Level 0 data source | |
| ddm_time_type_selector | DDM sample time type selector | |
| ddm_timestamp_gps_sec | DDM sample timestamp - GPS Seconds | second |
| ddm_timestamp_gps_week | DDM sample timestamp - GPS Week | week |
| ddm_timestamp_utc | DDM sample timestamp - UTC | seconds since 2018-08-02 00:00:00.999261576 |
| delay_resolution | DDM delay bin resolution | 1 |
| dopp_resolution | DDM Doppler bin resolution | s-1 |
| eff_scatter | DDM bin effective scattering area | meter2 |
| fresnel_coeff | Fresnel power reflection coefficient at specular point | 1 |
| fsw_comp_delay_shift | Flight software DDM compression delay shift | 1 |
| fsw_comp_dopp_shift | Flight software DDM compression Doppler shift | s-1 |
| gps_ant_gain_db_i | GPS SV transmit antenna gain | dBi |
| gps_eirp | GPS effective isotropic radiated power | watt |
| gps_off_boresight_angle_deg | GPS off boresight angle | degree |
| gps_tx_power_db_w | GPS SV transmit power | dBW |
| inst_gain | Instrument gain | 1 |
| les_mod | The model observable | 1 |
| les_scatter_area | LES scattering area | meter2 |
| les_tw_outlier | Track-wise corrected observable is an outlier | 1 |
| les_tw_r2 | The R^2 correlation coefficient of the track-wise linear regression | 1 |
| les_tw_slope | The slope of the track-wise correction | 1 |
| les_tw_yint | The y-intercept of the track-wise correction | 1 |
| lna_noise_figure | LNA noise figure | dB |
| lna_temp_nadir_port | Port Antenna LNA temperature | degree_Celsius |
| lna_temp_nadir_starboard | Starboard antenna LNA temperature | degree_Celsius |
| lna_temp_zenith | Zenith Antenna LNA temperature | degree_Celsius |
| merra2_wind_speed | 10m MERRA-2 reference wind speed | m s-1 |
| nbrcs_mod | The model observable | 1 |
| nbrcs_scatter_area | NBRCS scattering area | meter2 |
| nbrcs_tw_outlier | Track-wise corrected observable is an outlier | 1 |
| nbrcs_tw_r2 | The R^2 correlation coefficient of the track-wise linear regression | 1 |
| nbrcs_tw_slope | The slope of the track-wise correction | 1 |
| nbrcs_tw_yint | The y-intercept of the track-wise correction | 1 |
| nst_att_status | NST attitude status | |
| power_analog | DDM bin analog power | watt |
| prn_code | GPS PRN code | 1 |
| prn_fig_of_merit | PRN selection figure of Merit | 1 |
| pvt_timestamp_gps_sec | PVT timestamp - GPS Seconds | second |
| pvt_timestamp_gps_week | PVT timestamp - GPS Week | week |
| pvt_timestamp_utc | PVT timestamp - UTC | seconds since 2018-08-02 00:00:00.999261576 |
| quality_flags | Per-DDM quality flags 1 | |
| quality_flags_2 | Per-DDM quality flags 2 | |
| raw_counts | DDM bin raw counts | 1 |
| rx_clk_bias | GPS receiver clock bias | meter |
| rx_clk_bias_pvt | GPS receiver clock bias at PVT time | meter |
| rx_clk_bias_rate | GPS receiver clock bias rate | meter s-1 |
| rx_clk_bias_rate_pvt | GPS receiver clock bias rate at PVT time | meter s-1 |
| rx_to_sp_range | Rx to specular point range | meter |
| sample | Sample index | 1 |
| sc_alt | Spacecraft altitude | meter |
| sc_lat | Sub-satellite point latitude | degrees_north |
| sc_lon | Sub-satellite point longitude | degrees_east |
| sc_pitch | Spacecraft attitude pitch angle at DDM sample time | radian |
| sc_pitch_att | Spacecraft attitude pitch angle at attitude time | radian |
| sc_pos_x | Spacecraft position X at DDM sample time | meter |
| sc_pos_x_pvt | Spacecraft position X at PVT time | meter |
| sc_pos_y | Spacecraft position Y at DDM sample time | meter |
| sc_pos_y_pvt | Spacecraft position Y at PVT time | meter |
| sc_pos_z | Spacecraft position Z at DDM sample time | meter |
| sc_pos_z_pvt | Spacecraft position Z at PVT time | meter |
| sc_roll | Spacecraft attitude roll angle at DDM sample time | radian |
| sc_roll_att | Spacecraft attitude roll angle at attitude time | radian |
| sc_vel_x | Spacecraft velocity X at DDM sample time | meter s-1 |
| sc_vel_x_pvt | Spacecraft velocity X at PVT time | meter s-1 |
| sc_vel_y | Spacecraft velocity Y at DDM sample time | meter s-1 |
| sc_vel_y_pvt | Spacecraft velocity Y at PVT time | meter s-1 |
| sc_vel_z | Spacecraft velocity Z at DDM sample time | meter s-1 |
| sc_vel_z_pvt | Spacecraft velocity Z at PVT time | meter s-1 |
| sc_yaw | Spacecraft attitude yaw angle at DDM sample time | radian |
| sc_yaw_att | Spacecraft attitude yaw angle at attitude time | radian |
| sp_alt | Specular point altitude | meter |
| sp_az_body | Specular point body frame azimuth angle | degree |
| sp_az_orbit | Specular point orbit frame azimuth angle | degree |
| sp_ddmi_delay_correction | Correction to DDMI specular point delay | 1 |
| sp_ddmi_dopp | DDMI Doppler at specular point | s-1 |
| sp_ddmi_dopp_correction | Correction to DDMI specular point Doppler | s-1 |
| sp_delay_error | Flight software specular point delay error | 1 |
| sp_dopp_error | Flight software specular point Doppler error | s-1 |
| sp_fsw_delay | Flight software specular point delay | 1 |
| sp_inc_angle | Specular point incidence angle | degree |
| sp_lat | Specular point latitude | degrees_north |
| sp_lon | Specular point longitude | degrees_east |
| sp_pos_x | Specular point position X | meter |
| sp_pos_y | Specular point position Y | meter |
| sp_pos_z | Specular point position Z | meter |
| sp_rx_gain | Specular point Rx antenna gain | dBi |
| sp_theta_body | Specular point body frame theta angle | degree |
| sp_theta_orbit | Specular point orbit frame theta angle | degree |
| sp_vel_x | Specular point velocity X | meter s-1 |
| sp_vel_y | Specular point velocity Y | meter s-1 |
| sp_vel_z | Specular point velocity Z | meter s-1 |
| spacecraft_id | CCSDS spacecraft identifier | 1 |
| spacecraft_num | CYGNSS spacecraft number | 1 |
| static_gps_eirp | Static GPS effective isotropic radiated power | watt |
| status_flags_one_hz | 1 Hz Status Flags | |
| sv_num | GPS Space Vehicle Number | 1 |
| track_id | DDM Track ID | 1 |
| tw_num | Number of samples used in the track-wise linear regression | 1 |
| tx_clk_bias | GPS transmitter clock bias | meter |
| tx_pos_x | GPS Tx position X | meter |
| tx_pos_y | GPS Tx position Y | meter |
| tx_pos_z | GPS Tx position Z | meter |
| tx_to_sp_range | Tx to specular point range | meter |
| tx_vel_x | GPS Tx velocity X | meter s-1 |
| tx_vel_y | GPS Tx velocity Y | meter s-1 |
| tx_vel_z | GPS Tx velocity Z | meter s-1 |
| zenith_code_phase | Zenith signal code phase | 1 |
| zenith_sig_i2q2 | Zenith Signal I2Q2 | 1 |
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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. 2021. CYGNSS Level 1 Climate Data Record Version 1.1. Ver. 1.1. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/CYGNS-L1C11
For more information see Data Citations and Acknowledgments.
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| 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 |
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| Version | Dataset | Version Date | Status | |
|---|---|---|---|---|
| 3.2 | CYGNSS Level 1 Climate Data Record Version 3.2 | 2024-04-10 | ACTIVE | 2024-04-10T19:40:00.000Z |
| 1.2 | CYGNSS Level 1 Climate Data Record Version 1.2 | 2022-05-19 | ACTIVE | 2022-05-19T21:15:00.000Z |
| 1.1 | CYGNSS Level 1 Climate Data Record Version 1.1 | 2022-04-11 | ACTIVE | 2022-04-11T16:51:00.000Z |
| 1.0 | CYGNSS Level 1 Climate Data Record Version 1.0 | 2021-04-22 | COMPLETE | 2021-04-22T15:18:00.000Z |