TOPEX/POSEIDON Wind/Wave product: data set description page


Data set source
Data use
Information on available Data
Data Processing
Data format
References
Data selection page

Data set source

  • TOPEX/POSEIDON satellite
    • Significant wave height and Average wind speed (5 km x 5 km) along the path viewed by the altimeter. One data each second (relative satellite speed 6 m/s). Calibrated for wind < 25 m/s.

    The TOPEX-POSEIDON WIND/WAVE product was prepared by the CLS/AVISO Operations Center, 8-10,rue Hermes 31526 Ramonville St-Agne FRANCE Contact: Frederique Blanc e-mail:blanc@atlas.cnes.fr

    CLS consents that the FASTEX Central Archive distributes its products to the FASTEX Scientists. The following Data Use has to be applied on the TOPEX-POSEIDON WIND/WAVE product.

    Data use :

  • ACKNOWLEDGEMENT

    When using AVISO data products in a publication, please cite the origin of the data and the AVISO handbook describing the product. Please also send a copy of the article to Frederique Blanc (CLS).

  • COPYRIGHTS

    Copyright CNES and NASA for the year(s)of the altimetric observations for TOPEX/POSEIDON data
    Copyright CLS 1997 for derived produits on CD ROM
    Unauthorized copy is prohibited.
    Unauthorized commercial use is prohibited.
    All publications and other publicity material resulting from work carried out using these products shall clearly state that CNES/NASA TOPEX/POSEIDON data and CLS products have been used.


    • Information on available data in the FASTEX Central Archive

  • native binary format or ASCII format
  • between 19970101:00Z and 19970301:00Z
  • Data included in the FASTEX area (20N-90N, 140W-40E)

    • Data processing

    The wind/wave product has been derived from the T/P GDR-M altimetric product by extracting the parameters related to wind/waves in order to produce a dedicated and less voluminous file.

  • Domain:

    A data file contents the data from one satellite pass, when they are included in the FASTEX area (20N-90N, 140W-40E).

    • Data format

    Products consist of ten-day repeat cycles of data. Each copy of a part of the CLS CD ROM duplicates the original files organization : a directory for each cycle, with one cycle header file and a maximum of 254 pass-files.

    The data elements of a Wind/Wave pass file concern: time, location, attitude, significant wave height, backscatter coefficient, wind speed and flags.

    The Wind/Wave pass files are available both in their native format (binary format, provided with a subroutine to read the files) or in ASCII format, where each scientific record of the files where transformed in ASCII by the FASTEX Central Archive, using the subroutine provided by CLS.

    Format description :

    Each file contains a header of 27 lines, and N scientific data records.
    A scientific data record contains 36 fields.

    Pppp.dat / SCIENTIFIC DATA RECORD n
    Field
    Number     		Size Offset Mnemonic Content Type Unit
    1 2 1 Tim_Moy_1 Time, day part SI day
    2 4 3 Tim_Moy_2 Time, millisecond part SI 10-3 s
    3 2 7 Tim_Moy_3 Time, microsecond part SI 10-6 s
    4 4 9 Lat_Tra Latitude SI 10-6 deg
    5 4 13 Lon_Tra Longitude SI 10-6 deg
    6 1 17 Att_Wvf Attitude (waveform estimate) I 10-2 deg
    7 1 18 Att_Ptf Attitude (platform estimate) I 10-2 deg
    8 2 19 SWH_K Significant Waveheight (Ku) I 10-2 m
    9 2 21 SWH_C Significant Waveheight (C) I 10-2 m
    10 1 23 SWH_RMS_K RMS of significant waveheight
    elementary measurements (Ku)     		I 10-2 m
    11 1 24 SWH_RMS_C RMS of significant waveheight
    elementary measurements (C)     		I 10-2 m
    12 1 25 SWH_Pts_Avg Number of elementary valid
    points used to compute SWH (KU)     		SI -
    13 1 26 Net_Instr_SWH_
    Corr_K     		Net instrument correction to
    significant waveheight (Ku)     		SI 10-1 m
    14 1 27 Net_Instr_SWH_
    Corr_C     		Net instrument correction to
    significant waveheight (C)     		SI 10-1 m
    15 2 28 DR(SWH/att)_K Attitude Corection on the range
    (Ku)     		SI 10-3 m
    16 2 30 DR(SWH/att)_C Attitude Corection on the range (C) SI 10-3 m
    17 2 32 Sigma0_K Backscatter coefficient (Ku) I 10-2 dB
    18 2 34 Sigma0_C Backscatter coefficient (C) I 10-2 dB
    19 2 36 AGC_K Automatic Gain Control (Ku) I 10-2 dB
    20 2 38 AGC_C Automatic Gain Control (C) I 10-2 dB
    21 2 40 AGC_RMS_K RMS of AGC elementary data (Ku) SI 10-2 dB
    22 1 42 AGC_RMS_C RMS of AGC elementary data (C) I 10-2 dB
    23 1 43 Att_Sig Atmospheric attenuation
    correction to sigma0     		I 10-2 dB
    24 2 44 Sco_Sig Net instrumental correction to
    sigma0     		SI 10-2 dB
    25 2 46 Net_Instr_AGC_
    Corr_K     		Net instrumental correction to
    AGC (Ku)     		SI 10-2 dB
    26 2 48 Net_Instr_AGC_
    Corr_C     		Net instrumental correction to
    AGC (C)     		SI 10-2 dB
    27 1 50 AGC_Pts_Avg Number of elementary valid
    points used to compute AGC     		SI -
    28 1 51 Wind_Sp Modulus of Wind Speed I 10-1 m/s
    29 1 52 ALTON Altimeter indicator SI -
    30 1 53 Instr_State_Topex States of Topex Altimeter BF -
    31 1 54 Val_Att_Ptf Platform attitude validity SI -
    32 1 55 Alt_Bad_1 T and P measurement conditions
    (1)     		BF -
    33 1 56 Alt_Bad_2 T and P measurement conditions
    (2)     		BF -
    34 1 57 Geo_Bad_1 Ocean/Land/Ice index BF -
    35 1 58 Geo_Bad_2 Rain/tide conditions BF -
    36 2 59 Spares - char*2 -

    References

    AVISO USER HANDBOOK: WIND/WAVE PRODUCT
    Updated: 18 Mar 1998

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