Format of MST radar vector wind data files

Users are encouraged to make use of Version-2 Cartesian files.
Click here to find out more about the different versions of the signal processing.

File contents
These files contain 12 minute averaged profiles of the eastward, northward and upward components of the wind. The same data are stored in both binary files (described here) and ASCII files (described here).
Click here to find out about the contents of other files.

File naming convention:

YY is a 2-digit year [00 - 99]
MM is a 2-digit month [01 - 12]
DD is a 2-digit day [01 - 31]
Click here for the background to the file naming convention.

File location: /badc/mst/data/mst-products-v0/vector/
Click here for the location of other files.

Archiving convention: YYYY
Click here for a further explanation.

File availability
1990 to the present.

File format
The data are recorded in non-standard format binary files as descibed below:

                        VECTOR WINDS FILE

        File name :- VCFyyMMdd.DAT  where yyMMdd is the date.

        RECORD - 40 BYTES

        Data is FORMATTED unless stated otherwise.
        For UNFORMATTED data:-
        B = BYTE
        I2 = INTEGER*2 (2 byte integer)


        Each VCF file contains the processed vector wind data from the MST 
        radar for one day.

        The VCF file is formed by concatenating all the Vector Wind (VW) files
        obtained on one day.  These VW files have filenames
        VWyyMMdd_hhmm.nn where hhmm is the time (UT) of the start
        of that data subset and nn is the duration in minutes. 

        Various types of record are present :-

        Fixed Parameter records provide information about the radar site 
        and the way that the data were collected and processed.
        Data Header records introduce sets of data records.
        Data records contain the height information and vector wind 
        components that constitute a wind profile.

        Some records have an I1 identification field at the start.

        Each set of vector winds is calculated from the radial winds along 
        three beam directions (ie three dwells), after averaging many
        repetitions of a cycle of dwells.

        Where a cycle of dwells includes more than three beam directions 
        eg NE6 VRT NW6 NE12 VRT NW12, separate wind profiles have been
        computed eg from NE6 VRT NW6 and from NE12 VRT NW12. 
        The resulting (two) wind profiles are thus almost simultaneous,
        as the data was interleaved over many such cycles.

        The timing of the data can be read from the Vector Wind Headers 
        (or the associated VW Filenames).

        The fixed parameter records only occur once, at the
        start of the VCF file after the first VW file name.
        The data header records precede the data records to which
        they apply. 
        Ident   Record                          Comment
        None    Name of VW data file.           Name of Vector wind file
                                                that the data came from.
         1      Site parameters                 Before first VW file only.
         2      Radar fixed parameters.            ''    ''     ''  ''
         3      Antenna parameters, beam 0.        ''    ''     ''  ''
         3        etc.                             ''    ''     ''  ''
         3      Antenna parameters, beam 15.       ''    ''     ''  ''
         4      Peak extraction parameters.        ''    ''     ''  ''

              DATA HEADERS:
        None    Dwell header                    for the first dwell used in
                                                the vector calculations.
        None    Dwell header                    For the second dwell.
        None    Dwell header                    For the third dwell.
         8      Vector wind header.             date / mean time,
                                                time taken,no. of heights.
        None    Height & 3 Wind vectors.        starts the first wind profile
        None    Height & 3 Wind vectors.
                  etc.                          to the end of the wind profile

              DATA HEADERS
              DATA                              for the next wind profile
              DATA HEADERS
                  etc.                          to the end of the VW file    

        None    Name of VW data file.           Name of next Vector Wind file
              DATA HEADERS                                   
              DATA                              the next wind profile
         0      Trailer.


        Vector file name record.
        Name of VW file data came from.                 A20

        Site parameter record.
          Parameters relating to the radar site.

        Identifier for Site parameter record ( 1 ).     I1
        Latitude, degrees North.                        F9.3
        Longitude, degrees East.                        F9.3
        Altitude, metres above mean sea level.          F7.1
        Site name.                                      A18

        Radar fixed parameter record.
          Fixed parameters relating to the radar system.

        Identifier for Fixed Parameters Record ( 2 ).   I1
        Radar transmit frequency, MHz.                  F8.3
        Range sampling interval, microsecs.             F7.3
        Range of height bin zero, Km.                   F8.2

        Antenna parameter records.
          Information relating to the antenna beams :

        Identifier for Antenna parameter Record ( 3 ).  I1
        Nominal beam direction, eg NW6.                 A5
        Bearing, degrees East of North.                 F8.2
        Zenith angle, degrees.                          F6.2
        Beam width, degrees.                            F6.2

        Peak extraction parameter record.
          Contains parameters relating to the methods used to find the
          spectral peak and estimate the doppler shift.

        Identifier for Peak Extraction Record ( 4 ).    I1
        Algorithom number.                              I3
        Peak width factor.                              F6.2
        DC spike removal parameters.                    4I3
        S/N ratio threshold (dB)                        F7.1

        Dwell header record
          Information relating to a dwell.

          The following data is UNFORMATTED.

        Dwell number in cycle.                          I2
        Antenna beam number.                            I2
        Radar pulse length, microsecs.                  I2
        Complementary code number.                      I2
        Pulse repetition interval, microsecs.           I2
        Preprocessor integration count.                 I2
        Length of FFT.                                  I2
        Number of FFTs that have been averaged.         I2
        Receiver filter (microsecs) (1/bandwidth)       I2
        MST run number.                                 I2 
        Mean time, yy MM dd  hh mm ss .               6*B
        First height bin range (NH1,NH2).             2*I2
        Second height bin range ( NH3,NH4 ).          2*I2
        Height bin increment.                           I2

        Vector wind header record.
          Introduces a set of wind vector records.

        Identifier for Wind Vector Header ( 8 ).        I1

          The following data is UNFORMATTED.

        Start time,  yy mm dd  hh mm ss .             6*I2
        Duration of data collection, secs.              I2
        Number of wind vector records.                  I2 

        Wind vector record.
          The vector winds at given heights.

          The following data is UNFORMATTED.

        Height above mean sea level, (metres * 10)      I2
        The wind velocity components, E,N,V, cm/sec.  3*I2

        Each data record includes 5 vector sets ( 20*I2 = 40 bytes).
        The last record of a wind profile usually has less.

        Trailer record.
          Marks the end of the file.

        Identifier for Trailer Record ( 0 ).            I1

        This description was last updated 16 February 1995.

Internal Links:
Return to the top of the page
Gaining access to the data
File naming convention
Data archiving convention
Data locations
The differences between signal processing versions
The contents of other data files