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THE NERC MST RADAR FACILITY AT ABERYSTWYTH
FILE FORMAT FOR VERSION-3 MST RADAR CARTESIAN DATA
File contents
Thirty minute averages of the st300 v3 Cartesian data products (i.e. those covering the approximate altitude range 2 - 20 km at 300 m resolution) are sent to the Met Office for assimilation into their operational numerical weather prediction model. Each message contains altitude profiles of the following: horizontal wind speed and direction, vertical wind velocity, and vertical beam radar return signal power. The accuracy of the time-averaged horizontal wind data is thought to be higher than that of the single cycle data. This accuracy is quantified by monthly model-comparison statistics produced by the Met Office.

Availability They are currently available from 2006/03/16.

File naming convention:
ABWWP_YYYYMMDD_HHMM.txt for files with date-time stamps starting from 2006/08/16 10:00
ABYWP_YYYYMMDD_HHMM.txt for files with date-time stamps starting before 2006/08/16 09:30

YYYY is a 4-digit year [1990 - ]
MM is a 2-digit month [01 - 12]
DD is a 2-digit day [01 - 31]
HH is a 2-digit hour [00 - 23]
MM is a 2-digit minute [00 | 30]

For messages with date-time stamps for 2009/01/15 12:30 and later, the date-time information represents the END of the 30 minute averaging period. For messages with earlier date-time stamps, the date-time information represents the beginning of the averaging period.

File location:
Met Office messages are not available through the BADC but can be provided to data users on request.

File format: These files adopt a simple ASCII format defined by the Met Office. The first 8 lines of the file ABWWP_20100114_0000.txt are shown as follows:
10 01 14 00 00
130
 1685  0  260   3.1  0  -0.04  109  109  109
 1835  0  259   3.1  0  -0.11  110  110  110
 1984  0  250   2.6  0  -0.05  114  114  114
 2133  0  264   2.6  0  -0.06  118  118  118
 2282  0  256   2.9  0  -0.08  116  116  116
 2431  0  248   2.6  0  -0.02  120  120  120
The first two lines contain header information and all subsequent lines contain profile data:
Line 1 contains the date-time stamp as YY MM DD HH MM. Note that the year information (YY) is only given in 2 digit format. For messages with date-time stamps for 2009/01/15 12:30 and later, the date-time information represents the END of the 30 minute averaging period. For messages with earlier date-time stamps, the date-time information represents the beginning of the averaging period.

Line 2 contains a single integer which defines the number of profile data lines which follow.

Lines 3 onwards contain profile data in the following order:
Value 1 - integer - altitude of the (middle of the) range gate above mean sea level (m)

Value 2 - integer - reliability flag for values 3 and 4. A flag value of "0" implies that the associated values are reliable and a value of "1" implies that they are not. Note that this is the opposite of what is commonly found in other files. This value is set to "1", i.e. suggesting unreliable data, irrespective of actual data quality for all range gates with altitudes above 15 km starting from 2009/01/30 12:00.

Value 3 - integer - horizontal wind (from) direction (°), i.e. following the meteorological convention.

Value 4 - float - horizontal wind speed (m s-1).

Value 5 - integer - reliability flag for values 6 - 9. A flag value of "0" implies that the associated values are reliable and a value of "1" implies that they are not. Note that this is the opposite of what is commonly found in other files.

Value 6 - float - upward component of wind velocity (m s-1).

Value 7 - integer - vertical beam radar return signal power (dB).

Values 8 and 9 are repeats of value 7 and so can be ignored.

Internal Links:
Return to the top of the page
An overview of v3 signal processing
File format for unaveraged v3 Cartesian data products.
Page maintained by David Hooper
Last updated 14th January 2010