telegraphic codes and message practice, 1870-1945
It was evidently possible to study with advantage, the progress of atmospheric changes only when the telegraph lines had become widely extended over the earth's surface.
Cleveland Abbe, "Historical Notes on the Systems of Weather Telegraphy, and especially their Development in the United States." American Journal of Science and Arts, 3rd. ser. 2 (1871) 81-88
Meteorology developed in the nineteenth century on the back of telegraph and cable networks, by which widely scattered stations could submit their observations to a central point. Those "synoptic weather observations" were — and are today — made periodically, e.g., 8:00 am and 8:00 pm, and cover data on sky cover, state of the sky, cloud height and description, maximum and minimum temperatures, wind speed and direction, special conditions, &c. It is hard to imagine meteorology and weather prediction in the absence of the intelligence exchanged over telegraph networks.
Aeronautics was a second factor that pushed meteorology in new directions — mainly up; in so doing, aeronautics also vastly increased the need for observational data. Conventional land-based observations and their telegraphed transmissions weren't up to the new requirements; telegraphy, it was charged, imposed restrictions on the number of observations that could be transmitted, so complex and expensive was a telegraphed message (Friedman 1989: 146-49). This might be debated : witness the density of data that could be packed into a single word or 11-figure cipher by use of a cotton or chain and sectional cipher code, for example. But telegraphy was not static, and continued to evolve and even morph into different forms. Examples include the gradual transition to numeric codes in the 1930s, and the logical move toward telemetry from radiosondes.
Coded telegraphic messages involved structuring of data, if only by virtue of the structure provided by the codebook's tables and sequences. Meteorological codes represent the summa of that structuring : sequential assembly of formulaic message components, in a rule-bound process that would evolve through teletype symbol weather reports and on to telemetric rulesets like the National Weather Service's .
Gathered on this and linked pages are transcriptions of historical material on the role of telegraphy in meteorology, extended descriptions of some weather and related codes, and some annotated links to material available elsewhere. These are arranged chronologically below.
It might be said that meteorological telegraphy would come to abandon human users at the level of coding and decoding, as sensor devices and processing itself became automated. SHEF is a "documented set of rules for coding of data in a form for both visual and computer recognition... designed for interagency sharing of data, visual and machine readability." It takes data fed from automated sensors — data sequence identified in a header line — and "fully qualifies the data so that receiving databases have all the necessary information to describe the data."
Telegraphy is woven into the literature of and on meteorology, including —