THE NERC MST RADAR FACILITY AT ABERYSTWYTH
Click here to find out more about the different versions of the signal processing.
File contents
These files contain profiles of the eastward, northward and upward components of the wind. The same format is used for both unaveraged and 12 minute averaged data files.
Click here to find out about the contents of other files.
File naming convention:
 |
Unaveraged | |
vhYYMMDD.gz |
| 12 minute averaged | vecYYMMDD.gz |
|
YY | |
is a 2-digit year [00 - 99] |
| MM | is a 2-digit month [01 - 12] | ||
| DD | is a 2-digit day [01 - 31] | ||
| gz | indicates that the file is compressed with the GNU gzip algorithm |
Click here for the background to the file naming convention, and here for to find out how to deal with compressed files.
NOTE for Windows-based users. WinZip gives rise to an unexpected change of name from vhYYMMDD.gz to vecYYMMDD when uncompressing (owing to the fact that the original file was first compressed, and then renamed). It is not, therefore, possible to distinguish between uncompressed files for unaveraged and 12 minute averaged wind data based on the name. This problem is not encountered on Linux/Unix systems.
File location:
|
Unaveraged | |
/badc/mst/data/mst-products-v0/vw/ |
| 12 minute averaged | /badc/mst/data/mst-products-v0/vector/ |
Archiving convention: YYYY
Click here for a further explanation.
File availability
1989 to the present.
File format
The data are recorded in non-standard ASCII format files. The first twelve lines of the (unaveraged data) file for 3rd September 2001 are shown below by way of example below:
1 0.80 1 1 1 1 4.0
Lat. Long. Height Freq_Mhz Site
52.400 -4.000 50.0 46.50 Capel Dewi.
Run 1265 vw010903_0020.22
Dw Beam Date Time Bins Bins Tx Rx Pri Sum FFT Avg
1 NE6 D2001/09/03 Z00:20:50 L018:147 U000:000 8 2 320 512 128 1
3 VRT D2001/09/03 Z00:21:38 L017:147 U000:000 8 2 320 1024 64 1
4 SE6 D2001/09/03 Z00:22:01 L018:147 U000:000 8 2 320 512 128 1
Km East North Vert. m/s Heights= 120
1.70 -2.93 -22.11 1.55
1.85 -4.39 -22.04 1.80
2.00 6.05 -11.82 1.13
In the explanations of the different file components below, some of
the horizontal spacings have been altered for the sake of clarity. The
text shown in red is for descriptive purposes only and does not appear
in the files. The first 5 (header) lines, shown only once at the very
beginning of each file, do not contain any information needed to
extract or to interpret the data and so can be ignored.1 0.80 1 1 1 1 4.0 Lat. Long. Height Freq_Mhz Site 52.400 -4.000 50.0 46.50 Capel Dewi. Run 1265 vw010903_0020.22 Dw Beam Date Time Bins Bins Tx Rx Pri Sum FFT AvgWind profiles are calculated by combining the information from observations made in the vertical direction and at an off-vertical angle in two orthogonal azimuths. The next three lines contain the radar observation information for the three beam pointing directions used. Only the observation times are actually required to make use of the data. Since these times are typically within a couple of minutes of each other, it is aribitrary whether the profile time is taken to correspond to the first of these, the average or the middle value. Since a radar observation cycle typically involves more than three beam pointing directions, a profile is calculated for each possible combination. This means that for 12 minute averaged data, there will typically be two or three profiles within a few minutes of each other and then a gap of almost 12 minutes before the next set of profiles.
1 NE6 D2001/09/03 Z00:20:50 L018:147 U000:000 8 2 320 512 128 1 3 VRT D2001/09/03 Z00:21:38 L017:147 U000:000 8 2 320 1024 64 1 4 SE6 D2001/09/03 Z00:22:01 L018:147 U000:000 8 2 320 512 128 1 DWL BD YYYY/MM/DD hh:mm:ss RG1:RG2 RG3:RG4 PLEN RXBW IPP NCI LDFT NII
- DWL - Dwell number, i.e. the dwell
position in the sequence of observations made during each cycle
- BD - Nominal beam pointing direction
- YYYY/MM/DD - Observation date (year/month/day)
- hh:mm:ss - UT observation time (hour:minute:second)
- RG1:RG2 - Bottom and top range gates of the lower observation region
- RG3:RG4 - Bottom and top range gates of the upper observation region (equal to zero for ST mode observations)
- PLEN - Pulse length (us)
- RXBW - Receiver bandwidth (us)
- IPP - Inter-pulse period (us)
- NCI - Number of coherent integrations
- LDFT - Length of discrete Fourier transform
- NII - Number of incoherent integrations
- BD - Nominal beam pointing direction
Km East North Vert. m/s Heights= 120
1.70 -2.93 -22.11 1.55
1.85 -4.39 -22.04 1.80
2.00 6.05 -11.82 1.13
z u v w
- z - Altitude (km)
- u - Zonal velocity (m s-1), i.e. component of wind vector towards East (+ve)
- v - Meridional velocity (m s-1), i.e. component of wind vector towards North (+ve)
- w - Vertical velocity (m s-1), i.e. component of wind vector upwards (+ve)
- u - Zonal velocity (m s-1), i.e. component of wind vector towards East (+ve)