Accessing data from the World Radiation Data Centre

To obtain data from the World Radiation Data Centre Online Archive, you need only a conventional e-mail account that allows you to communicate with an Internet e-mail account.

Using simple commands in a message written with your e-mail editor, you specify data subsets from the archive that will be sent to you via e-mail. Although the command format is rigid, it is a simple line-oriented structure. If you wish to do more with the data than just read it, you will need an editor that allows you to cut the data from the return message and save it to a file. An editor that allows you to examine text lines up to 132 characters long is also desirable.

The command format for requesting information from the archive is typically a single word on one line (the DATA command requires additional parameters on additional lines).

Avoid including anything in your message other than commands

Your messages will generally be seen only by the system, not a person.
Any unrecognized verbiage will be returned to you as error messages.
Text you may not have intended as commands may be misinterpreted as such.

The e-mail address for all automatic data transfers is: data@wrdc-mgo.nrel.gov

We suggest that you order the metadata files listed below before attempting to download solar radiation data.

Metadata

To obtain the information file you are now reading, mail the following command to the online archive:

INFO

To obtain a complete list of site names and site codes, mail the following command:

STATIONS

To obtain documentation on the data and data formats, mail the following command:

FORMATS

Data

To obtain a solar radiation data set, mail a command in the following four-line format. This initiates a data request and defines the parameters for each of three search categories:

    DATA
    SITE site1[ site2 ...siteN]
    MEAS measurement1[ measurement2 ...measurementN]
    YEAR year1[ year2 ...yearN]

where

"DATA" is a mandatory data request initiator

"SITE" is followed by one or more WMO site identification numbers (from the list available from the STATIONS command), or the word "ALL" for all available sites (see note below).

"MEAS" is followed by one or more of the measurement types listed below (omit the annotation):

	GLOBAL		(Global solar radiation) 
	DIFFUSE		(Diffuse solar radiation) 
	DOWNWARD	(Downward atmospheric radiation) 
	SUNSHINE	(Sunshine duration) 
	DIRECT		(Direct solar radiation) 
	TOTAL		(Net total radiation) 
	TERNET		(Net terrestrial surface radiation (upward)) 
	TERSURFACE	(Terrestrial surface radiation) 
	REFLECTED	(Reflected solar radiation) 
	SPECTRAL	(Spectral radiation components) 
	ALL		(All available measurements (see note below))

"YEAR" is followed by one or more four digit year numbers, or the word "ALL" to select all available years (see note below).

Other Commands

    SIZE n

Allows you to specify a maximum size (in kilobytes) for the return message. Some systems truncate messages beyond a threshold size. (For example, America Online limits messages to about 8K.) The default setting is 32K. You may specify a size up to 1024K (1 megabyte). The command format is the word SIZE followed by a number; for example, "SIZE 16" specifies a maximum message size of 16 kilobytes.


    NEWS

Sends a text file of news about the WRDC and the automated data distribution system.


    STOP

Forces the system to ignore all subsequent lines in the command message. When used as the last line of your message, this prevents the mailer from seeing automated signature lines inserted by your mail system. Such lines would normally be returned to you in error messages.

Notes:

All three categories must be present under the DATA command
Each DATA category must be on a separate line
Parameters for each DATA category must be on a single line
The wildcard "ALL" may appear only once among search categories
Only one instance of each command is allowed per message
Upper or lower case characters may be used for the commands
Blank lines may be inserted between commands

Examples

Example 1 (sends global and total data from three sites for 1991 and 1992):

DATA SITE 745456 34224 424334 YEAR 1991 1992 MEAS GLOBAL TOTAL Example 2 (sends format information, and all available measurements for one site for 1991; allows a message size of up to one-half megabyte; and sends the latest news posting):

FORMATSDATA SITE 93343 YEAR 1991 MEAS ALL SIZE 512 NEWS

(Updated January 1995)