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 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] |
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.
RANDOM ACCESS FILE - FORMATTED
RECORD - 40 BYTES
Data is FORMATTED unless stated otherwise.
For UNFORMATTED data:-
B = BYTE
I2 = INTEGER*2 (2 byte integer)
DATA IN VECTOR WIND (VCF) FILE
------------------------------
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).
RECORD ORDERING.
----------------
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.
FIXED PARAMETERS HEADER:
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.
DATA:
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
DATA
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
etc.
0 Trailer.
RECORD FORMATS.
---------------
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.