UK Hourly Solar Radiation data - .radt (radiation) file format

PLEASE NOTE: The file format described below refers to the Met Office Land Surface data (1900-2000) dataset which has been superseded by the Met Office MIDAS dataset (1853-present) at the BADC.

The surface observation data are in a simple ASCII format.

A list of UK stations for which the BADC holds .radt files is available (.radt stations).

The file name convention is (STATION_NAME)(YEAR).(MESSAGE_TYPE).(FILE_EXTENSION)

STATION_NAMES is the complete station name.
YEAR is the year expressed in full, ie 1998.
Description of the message types is available.
The file extension is .radt meaning that the file contains hourly radiation measurements.

These .radt files contain radiation amounts currently being reported.
In all cases, the file headers END_HOUR and COUNT define the observation period. Values are either for an hour or for 24 hours.

Approximately 103 UK stations report radiation, but almost all only report hourly global solar radiation and hourly diffuse solar radiation. Only three stations report direct irradiation.

24 hour values are usually for 0000-2359 on the stated day. Occasionally the period may be 09-09Z. An 09-09 period ends at 0900 on the stated day. There should only be one 24 hour report per station per day.

-999 indicates a missing value.

The first line of the data file are the fields headers (which are detailed in the table below).

The fields in the .radt data files are :

HEADER PARAMETER FIELDS COLUMNS UNITS COMMENTS

ID Station Ref. Number 1 1-8 - -

IDTYPE - 2 9-17 - -

MET_DOM Meteorological Domain 3 18-28 - Message types

YEAR Year 3 29-35 - 4 characters

MON Month 4 36-43 - 1 or 2 characters (from 1 to 12)

DAY Day 5 44-51 - 1 or 2 characters (from 1 to 31max)

END_HOUR Hour 6 52-61 - Hour of observation from 0 to 2300

COUNT Hour count 7 62-69 - See COUNT definition

GLOBAL Global Solar irradiation amount 8 70-77 W.hour/sq.m 'Global' radiation is that received from both the sun and the surrounding environment.

DIFFUSE Diffuse Solar irradiation amount 9 78-86 W.hour/sq.m 'Diffuse' radiation is that obtained when a shade ring is used to block out the sun's direct radiation.

DIRECT Direct Solar irradiation amount 10 87-94 W.hour/sq.m Global radiation is the amount of Direct and diffuse radiation which reaches the Earth's surface at a given location.

More information about the sunshine and radiation network is available in the documentation provided by the Met Office.

HEADER	PARAMETER	FIELDS	COLUMNS	UNITS	COMMENTS
ID	Station Ref. Number	1	1-8	-	-
IDTYPE	-	2	9-17	-	-
MET_DOM	Meteorological Domain	3	18-28	-	Message types
YEAR	Year	3	29-35	-	4 characters
MON	Month	4	36-43	-	1 or 2 characters (from 1 to 12)
DAY	Day	5	44-51	-	1 or 2 characters (from 1 to 31max)
END_HOUR	Hour	6	52-61	-	Hour of observation from 0 to 2300
COUNT	Hour count	7	62-69	-	See COUNT definition
GLOBAL	Global Solar irradiation amount	8	70-77	W.hour/sq.m	'Global' radiation is that received from both the sun and the surrounding environment.
DIFFUSE	Diffuse Solar irradiation amount	9	78-86	W.hour/sq.m	'Diffuse' radiation is that obtained when a shade ring is used to block out the sun's direct radiation.
DIRECT	Direct Solar irradiation amount	10	87-94	W.hour/sq.m	Global radiation is the amount of Direct and diffuse radiation which reaches the Earth's surface at a given location.