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Description

This dataset contains the version 3.2.1 CYGNSS level 3 science data record merged storm (MRG) wind speed which combines CYGNSS storm-centric gridded (SCG) wind speeds, which are derived from the L2 Young Seas Limited Fetch (YSLF) winds for a region surrounding a given tropical cyclone (TC), with L3 Fully Developed Seas (FDS) winds away from the TC center on a 0.2x0.2 degree latitude by longitude equirectangular grid obtained from the Delay Doppler Mapping Instrument aboard the CYGNSS satellite constellation.
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L3 MRG combines the L2 FDS and Young Seas Limited Fetch (YSLF) winds and eliminates the need to choose between them depending on sea state development and the proximity to storms. The data are provided in netCDF-4 format and extend from 1 August 2018 to the present with an approximate 6 day latency. A tapered weighted averaging scheme is used centered on the 25 m/s wind radius of the storm. The 34 knot wind radius (R34) algorithm has been updated for v3.2.1 release to center around the National Hurricane Center or the Joint Typhoon Warning Center (NHC/JTWC) reported storm center instead of the CYGNSS Vmax location. The algorithm produces global (+/- 40 deg latitude) wind speeds reported on a 0.1x0.1 deg grid every 6 hours for each tropical cyclone, although some 6-hourly increments may be missing if there are an insufficient number of satellite overpasses of the storm during that time interval. The netCDF files are output on a storm-by-storm basis.
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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.

Product Summary

Platforms
CYGNSS
Instruments
DDMI
Spatial Extent

N: 40 S: -40 E: 180 W: -180

Spatial Resolution
0.2 Decimal Degrees x 0.2 Decimal Degrees
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2018-08-01
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC) ,
Cyclone Global Navigation Satellite System Mission, NASA Earth Science System Pathfinder, University of Michigan (NASA/ESSP/UMICH/CYGNSS)
Concept ID
C3168812717-POCLOUD
Data State
DEPRECATED
Number of Files/Granules
2387
Processing Level
3
Published
Updated
Science Keywords
Wind Direction ,
Wind Speed

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

CYGNSS. (2024). CYGNSS Level 3 MRG Science Data Record Version 3.2.1 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/CYGNS-3M321 Date Accessed: 2025-12-13

Documents

USER'S GUIDE

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)

DATA PRODUCT SPECIFICATION

DATA CITATION GUIDELINES

GENERAL DOCUMENTATION

PUBLICATIONS

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
best_track_r34_ne In the north east quadrant, how far from the storm center do 34 knot winds exist as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product. km int -9999 N/A 1
best_track_r34_nw In the north west quadrant, how far from the storm center do 34 knot winds exist as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product. km int -9999 N/A 1
best_track_r34_se In the south east quadrant, how far from the storm center do 34 knot winds exist as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product. km int -9999 N/A 1
best_track_r34_sw In the south west quadrant, how far from the storm center do 34 knot winds exist as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product. km int -9999 N/A 1
best_track_storm_center_lat Latitude coordinate of the storm center at the given time as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product. degrees_north float -9999 N/A 1
best_track_storm_center_lon Longitude coordinate of the storm center at the given time as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product. degrees_east float -9999 N/A 1
best_track_storm_status The level of storm development as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product.: 0 = tropical depression 1 = tropical storm 2 = typhoon 3 = super typhoon 4 = tropical cyclone 5 = hurricane 6 = subtropical depression 7 = subtropical storm 8 = extratropical systems 9 = monsoon depression 10 = inland 11 = dissipating 12 = low 13 = tropical wave 14 = extrapolated 15 = unknown 16 = disturbance 17 = error 1 byte -99 N/A 1
best_track_vmax Maximum sustained wind speed in meters per seconds as reported by the National Hurricane Center&#039;s Tropical Cyclone Best Track data product. m s-1 int -9999 N/A 1
cygnss_r34_ne CYGNSS derived 34 knot wind radii in the north east quadrant. km float -9999 N/A 1
cygnss_r34_nw CYGNSS derived 34 knot wind radii in the north west quadrant. km float -9999 N/A 1
cygnss_r34_se CYGNSS derived 34 knot wind radii in the south east quadrant. km float -9999 N/A 1
cygnss_r34_sw CYGNSS derived 34 knot wind radii in the south west quadrant. km float -9999 N/A 1
cygnss_vmax_lat Estimate of the latitude coordinate of the maximum storm velocity made from the CYGNSS wind speeds. degrees_north float -9999 N/A 1
cygnss_vmax_lon Estimate of the longitude coordinate of the maximum storm velocity made from the CYGNSS wind speeds. degrees_east float -9999 N/A 1
epoch_time Timestamp coordinate is at the center of the 6 hr bin referenced by the historical Epoch reference date/time. The Epoch reference date/time corresponds to the first observation time window in the CYGNSS data record after the automatic gain control was turned off. Total number of timestamps in a file corresponds to the length of the storm. This value is rounded to the nearest hour since leap seconds may have occurred making the number of hours since the start of the mission not exact. hours since 2018-08-01 00:00:00.000000000 int N/A N/A 1
lat Latitude coordinate at the center of the 0.1 degree bin, degrees_north, at 0.1 degree resolution. Range is -39.9 .. 39.9. degrees_north float N/A N/A 1
lon Longitude coordinate at the center of the 0.1 degree bin, degrees_east, at 0.1 degree resolution. Range is 0.0 .. 359.9. degrees_east float N/A N/A 1
merge_method Method used for merging the FDS and SCG winds. 0 = Only FDS winds1 = Only SCG winds2 = No close SCG winds3 = Blending FDS and SCG winds4 = Using closest FDS winds 1 int -9999 N/A 1
quality_flags The per-time step quality flags. 1 indicates presence of condition. Flag bit masks: 1/0x00000001 = poor_overall_quality This flag is allocated for potential future flags. There are currently no fatal flags. 2/0x00000002 = low_quality_vmax Set if there were not enough valid wind speeds to properly smooth the winds to locate the Vmax. N/A int -9999 N/A 1
range_corr_gain Merged CYGNSS L3 Storm Centric Gridded andCYGNSS L3 FDS range corrected gains from their respective processings. 1e-27 dBi meter-4 float -9999 N/A 1
time Timestamp coordinate at the center of the 6 hr bin. The range length is unique to each storm. hours since 2023-06-28 00:00:00.000000000 int N/A N/A 1
time_offset Time offset of individual samples in lat,lon grid from Timestamp coordinate at the center of the +/- 6 hr bin. A negative(positive) value indicates the sample was measured before(after) the center time. hours float -9999 N/A 1
wind_speed Merged CYGNSS L3 Storm Centric Gridded and CYGNSS L3 FDS gridded wind speed. m s-1 float -9999 N/A 1
wind_speed_uncertainty Standard deviation of the error in the wind speeds within the bin. m s-1 float -9999 N/A 1
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