MetOp-A ASCAT Level 2 25-km Ocean Surface Wind Vector Climate Data Record
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Short NameASCATA_L2_25KM_CDR
DescriptionThis dataset represents the first historically reprocessed Level 2 ocean surface wind vector climate data record from the Advanced Scatterometer (ASCAT) on MetOp-A sampled on a 25 km grid. Products at 25-km sampling are less noisy than 12.5-km products, but also contain less geophysical information on small scales and near the coasts. The wind vector retrievals are currently processed using the CMOD7 geophysical model function using a Hamming filter to spatially average the Level 1 Sigma-0 data over 25 km swath grid cells. Each file corresponds to one complete orbit and is provided in netCDF version 3 format. The beginning of the orbit files is defined near the South Pole. ASCAT is a C-band fan beam radar scatterometer, providing two independent swaths of backscatter retrievals, aboard the MetOp-A platform in sun-synchronous polar orbit. It is a product of the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) Ocean and Sea Ice Satellite Application Facility (OSI SAF) provided through the Royal Netherlands Meteorological Institute (KNMI). For more information on the MetOp mission, please visit: For access to more contemporaneous and near-real-time MetOp-A ASCAT 25-km data, please visit: For more timely announcements, users are encouraged to register with the KNMI scatterometer email list: All intellectual property rights of the OSI SAF products belong to EUMETSAT. The use of these products is granted to every interested user, free of charge. If you wish to use these products, EUMETSAT's copyright credit must be shown by displaying the words "copyright (year) EUMETSAT" on each of the products used. Use cases and feedback on the products will be much appreciated and in fact helps to sustain the reprocessing capability.
Dataset TypeOPEN
MeasurementOCEANS > OCEAN WINDS > SURFACE WINDS > Ocean Surface Wind Vectors
Processing Level2
CoverageRegion: Global
Northernmost Latitude: 89.6 degrees
Southernmost Latitude: -89.6 degrees
Westernmost Longitude: 0 degrees
Easternmost Longitude: 360 degrees
Time Span: 2007-Jan-01 to 2014-Apr-01
Granule Time Span: 2007-Jan-01 to 2014-Apr-01
ResolutionSpatial Resolution: 25 km (Along) x 25 km (Across)
ProjectionType: Swath
Detail: Twin-Swath, each 512.5 km wide, sub-track (nadir) gap of 737.5 km
Ellipsoid: GEM6
Latency hours
Swath Width1800000 m
Sample Frequency-
Temporal Repeat (Nominal)12 Hour
Temporal Repeat (Min)1.7 Hour
Temporal Repeat (Max)5 Day
Name: Meteorological Operational Satellite - A (METOP-A)
Orbit Period: 101.3 minutes
Inclination Angle: 98.7 degrees
Ascending Node: 2007-Jan-01 21:30:00
Name: Advanced Scatterometer (ASCAT)
Swath Width: 1800 km
Description: Dual fan beam C-band (5.25 GHz) vertically polarized scatterometer, providing measurements across two 550 km swaths, separated by a 700 km nadir blind region. This dual swath configuration allows ASCAT to provide more than twice the daily coverage of the ERS 1 and 2 predecessors with a coverage of nearly 70% of the ice-free oceans each day.

ProjectMeteorological Operational (MetOp)
Data ProviderCreator: EUMETSAT/OSI SAF
Release Place: KNMI, Royal Netherlands Meteorological Institute
Release Date: 2018-Apr-23
Keyword(s)metop-a, metop, wind data, wind, ocean wind, wind speed, vector, vectors, ocean wind vector, ocean wind vectors, knmi, osi saf, eumetsat, climate, climate data record, cdr
Persistent IDPODAAC-ASCDR-25X01
Questions related to this dataset? Contact
User's Guide
CDR User Guide
ASCAT Level 2 CDR User Guide
Project Materials
ASCAT L2 Winds Data Record Validation Report Version
Verhoef, A., J. Vogelzang and A. Stoffelen, 2016: ASCAT L2 Winds Data Record Validation Report Version 1.2. Technical Note, SAF/OSI/CDOP2/KNMI/TEC/RP/239, EUMETSAT.
MetOp Mission Summary Page
Mission and Instrument Overview
KNMI/OSI-SAF Publications
Reports and Publications
Scatterometry Training Material
Training resources for scatterometry data provided by KNMI
Citation EUMETSAT/OSI SAF. 2018. MetOp-A ASCAT Level 2 25-km Ocean Surface Wind Vector Climate Data Record. Ver. 1.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at

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For more information see Data Citations and Acknowledgments.

Journal Reference Verhoef, A., J. Vogelzang, J. Verspeek and A. Stoffelen, Long-Term Scatterometer Wind Climate Data Records, IEEE Journal of Selected Topics in Applied Earth O, 2017, 10, 5, 2186-2194, doi:10.1109/JSTARS.2016.2615873.