UK Daily Weather data - Columns in the WD table

Table Description - Columns in the WD table - How to start filtering the rows of data out

The surface observation data are in a simple ASCII format.

Table Description:

This entity contains meteorological values measured on a 24 hour time scale. ob_end_time and ob_hour_count define the observation period. Sunshine duration, snow day, hail day, thunder day and gale day are usually for the period 0000-2359Z, i.e. ob_end_time = '2359' and ob_hour_count = 24. Concrete state, lying snow, snow depth, fresh snow depth and fresh mountain snowfall are "spot" values, usually at 0900Z, i.e. ob_end_time = 0900 and ob_hour_count = 0. Daily rainfall, daily radiation, daily temperature ranges and bare soil minimum temperatures are stored in separate entities. Day of fog at 0900Z is not included. MIDAS will store rows in this table using climatological station number, e.g. id_type = 'DCNN'. If the station does not have a DCNN, it will use id_type = 'WMO'. Attributes with different time scales are not compressed into a single row.

Columns in the WD table:

For the convenience of users, the WD file column headers are available for download in Excel or as a comma separated text file.

PK Attribute Description / Units
* ob_end_time Date and time at end of observation
* id  
* id_type Identifier type
* ob_hour_count Observation hour count
* version_num Observation version number - Use the row with '1', as this has been quality checked by the Met Office
* met_domain_name Message type
  src_id Unique source identifier or station site number
  rec_st_ind State indicator for the record**
  cs_24hr_sun_dur Campbell-Stokes sunshine duration
0.1 hr
  conc_state_id Concrete state code gives the state of a concrete slab (e.g. dry, wet, frozen, etc) of specified standard dimensions and composition at the observing station.
  lying_snow_flag Lying snow flag. Snow lying is counted, provided that the snow covers at least one-half of the ground easily visible from the station and the altitude of this ground does not differ by more than 30m from that of the station. In judging if at least one-half of the ground is snow covered no account is taken of bare patches under trees or of aeras occupied by water.
  snow_depth Snow depth
cm
  frsh_snw_amt Fresh snow amount
cm
  snow_day_id Snow day code
  hail_day_id Hail day code - A day of hail is defined as one when pieces of ice, 5mm or more in diameter are observed to fall. The hailstones can fall separately or be agglomerated into irregular lumps.
  thunder_day_flag Thunder day flag - A day of thunder is counted when thunder is heard.
  gale_day_flag Gale day flag - A day of gale is counted when a mean wind speed reaches or exceeds or is estimated to have reached or exceeded, 34kn (force 8 on the Beaufort scale) over a period of at least several minutes (10 mn in the case of a station equipped with an anemograph).
  frsh_mnt_snwfall_flag Fresh mountain snowfall flag
  wmo_24hr_sun_dur  
  cs_24hr_sun_dur_q QC code - Campbell-Stokes sunshine duration**
  conc_state_id_q QC code - concrete state code**
  snow_depth_q QC code - snow depth**
  frsh_snw_amt_q QC code - fresh snow amount**
  snow_day_id_q QC code - snow day code**
  hail_day_id_q QC code - hail day code**
  thunder_day_flag_q QC code - thunder day flag**
  gale_day_flag_q QC code - gale day flag**
  wmo_24hr_sun_dur_q  
  meto_stmp_time Met Office receipt stamp time
  midas_stmp_etime Elapsed time to storage in MIDAS
minutes
  drv_24hr_sun_dur Derived 24HR Sunshine duration
These stations are those with radiation sensors only which use the global radiation values to derive a 24hr sunshine value. This was incorrectly appearing under WMO 24hr sunshine when the value was not coming from a sunshine sensor so was moved into the DRV_24HR_SUN_DUR column.
  drv_24hr_sun_dur_q QC Code - Derived 24HR sunshine duration
  lying_snow_ht height of lowest lying snow (in decametres). Please note that the observer could enter the height of the lowest lying snow at station level. In this case the station height has been rounded to the nearest 10 metres and used. Observations made as part of the Snow Survey of Great Britain (1946-2007).
  lying_snow_ht_q QC - Lying snow height
LYING_SNOW_HT_Q gives a flag for both null and non-null values. For a null value a 0 flag means that there was no snow observed, 120 means that the reading is missing and 130 means that no observation was possible due to the hills being obscured.


** 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. snow_depth_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.