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Earth Topics (Applications)
  • Ocean and Coast
  • Ocean Waves

    Ocean Winds

    Sea Surface Temperature

    Instrument type
    Date of Launch:
    19 June 1999
    Mission Status:
    Operations ended in 2009
    Orbit Height:
    803 km
    Orbit type:
    Circular sun-synchronous polar
    Swath Width:
    1800 km
    QuikSCAT/L2A & L2B - topEX/GDR-M colocation
    (1100) recent views
    Last update: 23 January 2012

    This product provides a dataset colocating backscatter and wind measurements from SeaWinds scatterometer (L2A & L2B products from JPL/PO.DAAC), onboard QuikSCAT, together with measurements from the topEX American Altimeter (GDR-M product from CLS/AVISO).

    The QT product consists in the colocation of QuikSCAT/SeaWinds Level 2B datasets, and also - for investigators authorized by JPL/PO.DAAC  - Level 2A datasets, together with topEX/GDR datasets. Colocation areas are determined applying the following criteria: 25 km for the maximum distance between 2 measurements and 1 hours for the time window. Both minimal and total levels are available for this product.

    SeaWinds, the NASA scatterometer onboard QuikSCAT, is a rotating Ku band (13.4 GHz) microwave radar that measures the speed and direction of winds over the global ocean surface. Selected parameters from SeaWinds Level 2B product include wind vector solutions over 25km wind vector cells (WVC) for all four wind vector ambiguities as well as the Direction Interval Retrieval with Threshold Nudging (DIRTH) wind vector solution and rain probability indicators (since raindrops may affect the sigma-0 measurement and thus the wind vector solution). Radar backscatter values and related sensor parameters from SeaWinds/L2A product are also included for authorized users (default values otherwise).

    topEX, the NASA dual frequency (13.6 and 5.3 GHz) altimeter onboard topEX/POSEIDON, provides radar backscatter (sigma0), from which wind speed modulus, wave height and sea surface elevation can be retrieved. The GDR parameters selected in QT product include these measurements as well as complementary data (as brightness temperature at 18, 21 and 37 GHz) from the microwave sounder onboard the satellite.

    Each QT file of minimal level contains data for one full orbital revolution of QuikSCAT. These data are grouped by rows of 25km wind vector cells (WVC). Each row contains a total of 76 WVC values and corresponds to a single cross-track cut of the SeaWinds 1800 km wide swath. Only rows where colocation of at least one WVC with GDR-M measurements was possible are available in the product.

    Data Set Specifications
    Spatial coverage: 90 N, 90 S, 180 W, 180 E
    Temporal coverage: 1999-07-19 - 2009
    Processing level
    Level 2a
    Level 2b
    How to access this data

    Data are available through QuickSCAT website.

    Terms & Conditions applicable
    Utilisation of this data is subject to the Terms and Conditions for ESA's Third Party Missions scheme