RapidScat Level 2B Climate Ocean Wind Vectors in 12.5km Footprints Version 2.0

1 Publication Cited this Dataset
Citation metrics available for years (2014-2021)
Processing Level2
Start/Stop Date2014-Oct-08 to 2016-Aug-19
DescriptionThis dataset contains the RapidScat Level 2B 12.5km Version 2.0 Climate quality ocean surface wind vectors. The Level 2B wind vectors are binned on a 12.5 km Wind Vector Cell (WVC) grid and processed using the using the "full aperture" normalized radar cross-section (NRCS, a.k.a. Sigma-0) from the L1B dataset. RapidScat is a Ku-band dual beam circular rotating scatterometer retaining much of the same hardware and functionality of QuikSCAT, with exception of the antenna sub-system and digital interface to the International Space Station (ISS) Columbus module, which is where RapidScat is mounted. The NASA mission is officially referred to as ISS-RapidScat. Unlike QuikSCAT, ISS-RapidScat is not in sun-synchronous orbit, and flies at roughly half the altitude with a low inclination angle that restricts data coverage to the tropics and mid-latitude regions; the extent of latitudinal coverage stretches from approximately 61 degrees North to 61 degrees South. Furthermore, there is no consistent local time of day retrieval. The new version has two important improvements over the previous version 1.0. First, an SST-dependent GMF developed by Lucrezia Ricciardulli of Remote Sensing Systems is used in wind retrieval in order to fix persistent speed biases in Ku-band data over cold ocean. Second, flagging is simplified and extra flags are provided. All the previously existing flags are still there and still reflect the same meaning and purpose. A new single bit wind_retrieval_likely_corrupted_flag specifies the approximately 3% of the data which is known to have suboptimal performance due to rain, ice, or a few other rare anomalous cases. Another bit wind_retrieval_possibly_corrupted_flag specifies the approximately 15% of the data near rain, near ice, or near the coast, that is thought to be high quality but may not match up well with numerical wind models due to either remaining rain/ice/land contamination or variability in the winds near ice, rain, and coasts that are not reflected in the NWPs. In addition to these two new bits, copious quality information is provided in the data to allow users to tailor flags to meet their own needs. There is also an added a global attribute called rev_status that specifies whether the RapidScat Instrument was in the original (highest data quality) high SNR mode, or one of the four low SNR time periods, the latter of which indicates the accuracy of winds below 5 m/s is degraded. This attribute also serves to identify MARGINAL orbits in which there are large gaps in the data record due to suboptimal spacecraft attitude. Other than gaps in the data, the accuracy of the winds in the MARGINAL orbits are similar to other orbits. This dataset is provided in netCDF-4 format and made available via FTP and OPeNDAP. For data access, please click on the "Data Access" tab above.
Swath Width900 km
Name: International Space Station (ISS)
Orbit Period: 92.91 minutes
Inclination Angle: 51.65 degrees
Name: Rapid Scatterometer (RapidScat) (RapidScat)
Swath Width: 1100.0 kilometers
Description: Spacecraft angular distance from orbital plane relative to the Equator.

ProjectInternational Space Station Rapid Scatterometer (ISS_RapidScat)
Data ProviderPublisher: PO.DAAC
Creator: RapidScat Project
Release Place: PO.DAAC
Release Date: 2018-Apr-09
Resource: https://podaac.jpl.nasa.gov/ISS-RapidScat

Keyword(s)international space station, space station, iss, rapidscat, rscat, iss-rapidscat, winds, wind, ocean, ocean wind, ocean winds, ocean surface wind vectors, surface wind vectors, wind speed, wind direction, climate, clim, cdr, climate data record, scatterometer, quikscat, seawinds, l2b, l2, level 2, level 2b, version 1, v1, version 1.0, v1.0, V1.0, 1.0
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
Spatial Resolution: 12500 Meters x 12500 Meters
Temporal Resolution: Hourly - < Daily
North Bounding Coordinate: 61 degrees
South Bounding Coordinate: -61 degrees
West Bounding Coordinate: -180 degrees
East Bounding Coordinate: 180 degrees
Time Span: 2014-Oct-08 to 2016-Aug-19
Granule Time Span: 2014-Oct-08 to 2016-Aug-19
Swath Width: 900 km
Projection Type: Satellite native swath
Projection Detail: Geolocation information included for each pixel
Ellipsoid: WGS 84
NameLong NameUnit
ambiguity_directionwind direction ambiguitydegree
ambiguity_objwind objective function values1
ambiguity_speedwind speed ambiguitym s-1
atmospheric_speed_biasatmospheric speed biasm s-1
cross_track_wind_speed_biasrelative wind speed bias with respect to sweet spotm s-1
distance_from_coastDistance from nearest coastlinekm
eflagsextended wind vector cell quality flagsbit
flagswind vector cell quality flagsbit
gmf_sstSea Surface Temperature Used in Geophysical Model FunctionDegrees Celsius
nudge_wind_directionmodel wind directiondegrees
nudge_wind_speedmodel wind speedm s-1
num_ambiguitiesnumber of ambiguous wind directions found in point-wise wind retrieval prior to spatial filtering1
number_in_aftnumber of inner aft looks in wind vector cell1
number_in_forenumber of inner forward looks in wind vector cell1
number_out_aftnumber of outer aft looks in wind vector cell1
number_out_forenumber of outer forward looks in wind vector cell1
rain_impactimpact of rain upon wind vector retrieval1
retrieved_wind_directionequivalent neutral wind direction at 10 mdegrees
retrieved_wind_speedequivalent neutral wind speed at 10 mm s-1
retrieved_wind_speed_uncorrectedwind speed without rain correctionm s-1
timedate and timeseconds since 1999-1-1 0:0:0
time_diffRapidScat - Radiometer observation time differenceminutes
wind_objretrieved wind objective function value1
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 RapidScat Project. 2018. Rapidscat Level 2B Climate Ocean Wind Vectors in 12.5km Footprints Version 2.0. Ver. 2.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/RSX12-L2C20

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For more information see Data Citations and Acknowledgments.

Journal Reference [Special Note: This paper describes the wind retrieval algorithm used to process the QuikSCAT version 3 wind product. The RapidScat data was processed using the same technique, with the addition of utilizing the full aperture NRCS data.]

Fore, A. G., Stiles, B. W., Chau, A. H., Williams, B. A., Dunbar, R. S., Rodriguez E.. 2014. Point-wise wind retrieval and ambiguity removal improvements for the QuikSCAT climatological data set, IEEE Trans. Geoscience and Remote Sensing, 52, 1. https://doi.org/10.1109/TGRS.2012.2235843

VersionDatasetVersion DateStatus
2.0RapidScat Level 2B Climate Ocean Wind Vectors in 12.5km Footprints Version 2.02021-08-03COMPLETE2021-08-03T20:48:00.000Z
1.0RapidScat Level 2B Climate Ocean Wind Vectors in 12.5km Footprints2023-01-10COMPLETE2023-01-10T05:58:00.000Z