UK Mean Wind data - Columns in the WM table

Table Description:

• Wind and gust direction and speed measured over a WHOLE hour
  There may be hourly gust data from SYNOPs (with an id_type of WMO) where the gust speed is 25 knots or more. However these will be overwritten by later input - eg. hourly climate message data (from ESAWS or SAMOS), DALE tapes or Metform 6910.
• Mean value of wind speed for a 24 hour period, usually 09-09Z, obtained from run-of-wind.

• Ten minute winds recorded in SYNOPs and METARs - they are stored in the UK Hourly Weather table
• Mean speeds for 24 hours, obtained by meaning the hourly means - they are derived.

Columns in the WM table:

PK	Attribute	Description / Units
*	ob_end_time	Data and time at end of observation
*	id_type	Identifier type
*	id
*	ob_hour_count	Observation hour count
	met_domain_name	Message Type
*	version_num	Observation version number - Use the row with '1', as this has been quality checked by the Met Office
	src_id	Unique source identifier or station site number
	rec_st_ind	State indicator for the record**
	mean_wind_dir	Mean wind direction - The wind direction from which the wind blows, is measured in Degrees (true). The entry for an east wind is 090, that for a south wind 180 and so on clockwise. Note that zero values in both wind speed and wind direction fields indicate that there was no wind blowing at the time of observation. More... degs true
	mean_wind_speed	Mean wind speed knots. Wind mast elevations from selected stations are available here (MIDAS users only).
	max_gust_dir	Direction of maximum gust degs true
	max_gust_speed	Speed of maximum gust knots
	max_gust_ctime	Clock-time of maximum gust hhmm
	mean_wind_dir_q	QC code - mean wind direction**
	mean_wind_speed_q	QC code - mean wind speed**
	max_gust_dir_q	QC code - maximum gust direction**
	max_gust_speed_q	QC code - maximum gust speed**
	max_gust_ctime_q	QC code - maximum gust time**
	meto_stmp_time	Met Office receipt stamp time
	midas_stmp_etime	Elapsed time to storage in MIDAS minutes
	mean_wind_dir_j	Descriptor - mean wind direction**
	mean_wind_speed_j	Descriptor - mean wind speed**
	max_gust_dir_j	Descriptor - max gust direction**
	max_gust_speed_j	Descriptor - max gust speed**

** Details available to registered users only.

More information about the Met Office surface data is available in the documentation provided by the Met Office.

How to start filtering the rows of data out:

1. As the data arrive at the Met Office it undergoes quality control to check that the data are correct and consistent with the surrounding data points. Whether the process has occured or not is indicated by the version number (1 is the one to use as indicated in the table above).

2. To show the progress of the data through the quality control the various variables will have an associated _q value (e.g. mean_wind_dir_q). This _q value will have different values for each record (see details in table above).

3. While the Met Office MIDAS system overwrites the existing entry in their database the BADC's MIDAS entries do not as the BADC takes snapshots of the the MIDAS database from time to time leading to duplicate entries occuring in our archive. If duplicate records are found, check the associated meto_stmp_time to determine which record is the most recent one - this is the one to use and the other(s) can be ignored.