Cloud and Weather Symbols in the Historic Language of Weather Map Plotters

Abstract

Weather mapping began in the nineteenth century when telegraphs began sending simultaneous observations of conditions at the surface of Earth to weather stations around the world. Indicating the complexity of the clouds and weather seen at a site needed a common naming system and simple symbols that were independent of language, since telegraph signals crossed international borders. The first symbols representing clouds were abstracted and stylized versions of their artistic representations in naturalistic drawings and paintings. By the end of the nineteenth century, however, photography began to replace hand-drawn illustrations. Before the advent of color film, black and white photographs were sometimes even reproduced in colored inks using new mechanical printing processes. Nineteenth-century meteorologists developed symbols for various cloud types in the form of simple lines and curves suggestive of the pictures. In contrast, weather symbols (for rain, snow, fog, hail, etc.) were drawn largely from a lexicon of nonalphabetic written symbols, such as punctuation marks. Skilled map plotters used these simple symbols, suggestive of complex weather and clouds, to transfer telegraph and Teletype codes to visually meaningful hand-produced maps. The craft of manual weather map plotting reached an apex in the 1940s–60s. With advances in digital and satellite technology and automation of surface weather observations, the symbols used in traditional weather mapping have largely disappeared from daily use.