Data glossary
The following terms and definitions comprise the data header for our standard data files
WMO_NOWorld Meteorological Organisation (WMO) station number - used for identifying sites. These numbers are allocated by regions and countriesSRC_IDA unique database serial number used by the Met OfficeCITYThe primary name that is used to identify the site e.g. LondonSTN_NAMEThe secondary (optional) name used to identify unique sites withn a city e.g. London-Heathrow, London-London Weather CentreTYPEThe data type - climate, synop or forecastQCQuality control flag - 1- basic quality control only 2 - fully quality controlled data as used for settlementLATThe latitude for each site in degrees, tenths and hundredths.LONGThe longitude for each site in degrees, tenths and hundredths.ALTThe altitude of each site is the height above sea level measured in metres.DATEDates are expressed in the format dd/mm/yyyy. 'dd' is the day of the month with leading zero. 'mm' is the month 01-12. 'yyyy' is the year.DAILY_RAINIn the UK rainfall is measured at 0900 and 2100 UTC each day. The 24 hour total is for the period 0900 on the date given until 0900 the following day. In Europe rainfall is reported every 6 hours (0000, 0600, 1200 and 1800 UTC - Universal Time Co-ordinated). The 24 hour total for European sites is for the period midnight to midnight on the date given. Units of measurement are in millimetres and tenths.DAILY_MAX_TEMPThis is the highest temperature recorded at the reporting site. In the UK the maximum temperature is reported for the period 0900-0900 UTC the following day. Elsewhere the maximum temperature is reported at either 1800 UTC (for the period 1800 the previous day - 1800 on the current day) or at midnight (for the previous calendar day). All temperatures are recorded in degrees Celsius and tenths.DAILY_MIN_TEMPThis is the lowest temperature recorded at the reporting site. In the UK the minimum temperature is recorded at 0900 UTC (Universal Time Co-ordinated) each day and is the lowest value that has been reached during the preceeding 24 hour period. Minimum temperatures normally occur around dawn, which is why the value is assigned to the period ending at 0900 rather than to the previous day. Elsewhere minimum temperatures are recorded for the periods 0600 the previous day - 0600 UTC or for the period ending at midnight (for the calendar day) All temperatures are recorded in degrees Celsius and tenths.DAILY_MEAN_WINDMean wind speed is the average of each hourly recorded wind value throughout the day (midnight to midnight). Wind speeds are recorded using various types of anemometer sited on a mast 10 metres above ground level. They are sited at this height to remove the effect of trees and buildings. Values are expressed in metres per second.12Z_MSLPMean Sea Level Pressure is the local site pressure corrected to sea level. This is done so that pressure patterns can be analysed and contoured by meteorologists. If this was not done, then all pressure readings would effectively be measuring altitude. Units used are millibars Mb (or HectaPascals hPa). 1 Mb = 1 hPa12Z_REL_HUMThe relative humidity is a measure of the amount of water vapour actually in the air compared with the amount of water vapour that the air could hold (i.e. the amount required to saturate the air). This is expressed as a percentageSUNSHINEThe daily total of recorded bright sunshine, recorded using a Cambell Stoke sunshine recorder or equivilant. Units used are hours and tenths.DAILY_MAX_GUSTThe highest recorded wind gust measured between 0000 and 2359. Values are expressed in metres per second.
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