Beaufort, Sir Francis (1774-1857)

Irish admiral

Sir Francis Beaufort, British admiral and hydrographer to the Royal Navy, was the first in 1805 to introduce and describe a scale of wind for estimating wind strengths without the use of instruments, a system based on subjective observations of the sea. Because expansions to land conditions were later added to the Beaufort wind scale , and quantitative wind speed values were also supplemented to each category in 1926, the scale is still widely used to describe the wind's speed and strength. As well as the Beaufort wind scale, the Beaufort Sea in the Arctic Ocean is named after Sir Francis Beaufort.

Sir Francis Beaufort was born in County Meath, Ireland. His father was well known in the areas of geography and topography : he published one of the earliest detailed maps of Ireland. Sir Francis Beaufort's nautical career began at age 13 as a cabin boy in the British Navy. Three years later, he became interested in the weather , and started to write down short comments about the general weather. He was only 22 years old when he was promoted to a lieutenant. In 1805, he was given his first command on the naval ship H.M.S. Woolwich, and he was assigned a hydrographic survey in South America .

During these years, Beaufort developed the first version of his wind force scale and weather notation coding, which he used for his meteorological journals. Because Beaufort's weather journal entries were written daily, eventually even as frequently as every two hours, he needed a simple yet effective system of abbreviations for the weather conditions. He created a notation consisting of the wind force number from his wind force scale, and a one, two, or three-character alphabetical code describing the state of the sky and weather, even describing cloud conditions and precipitation types. He continued writing these meteorological journals until the end of his life.

Beaufort's next assignments were for a hydrographic study of the Eastern Mediterranean, and a patrol mission. He did a major surveying and charting around the Turkish coast, but in 1812, he was wounded by sniper fire during a conflict with local pashas, and later that year the Admiralty ordered him home due to his injury. In 1817, he wrote his experiences about this expedition in a book titled Karamania. Although he remained in the British Navy until he was 81, he did not returned to active sea duty. In 1829, Beaufort became hydrographer to the Admiralty, where he promoted hydrographic studies for several British expeditions.

Between 1831 and 1836, on the voyage of the Beagle, Beaufort's scale of wind force was used officially for the first time. In 1833, after some slight modifications, the Admiralty prescribed Beaufort's weather notation for all log entries in the British Navy. In 1838, the Admiralty also officially adopted the Beaufort wind scale for all ships. Beaufort became a Rear Admiral in 1846, and he was bestowed the title Knight Commander of the Bath in 1848. After 68 years of service, Sir Francis Beaufort retired from the Admiralty in 1855, and he died two years later in 1857.

Originally, the Beaufort wind scale was meant for ships, specifying the amount of sail that a full-rigged ship should carry under the various wind conditions. It consisted of 13 different degrees of wind strength, ranging from calm to hurricane. In 1838, the use of the Beaufort wind scale became mandatory for all log entries on the ships of the British Admiralty. When steamboats replaced sail ships, certain modifications were necessary to make for the international use in meteorological descriptions. In 1874, the International Meteorological Committee revised the original scale, mainly for usage in international weather telegraphs. The original Beaufort scale numbers needed to be changed such that instead of the sails on a frigate, they referred to states of the sea or degrees of motion of trees. This change was still not satisfactory, since some ambiguities soon arose. The last modification came in 1946, when the International Meteorological Committee extended the scale to 17 values by adding five values to refine the hurricane-force winds, and defined the scale values by ranges of the wind speed as measured at a height of 10 meters above the surface for each category. This concluded the transformation of the Beaufort wind force scale into the Beaufort wind speed scale.

Sir Francis Beaufort was an accomplished hydrographer, making thorough surveys of uncharted coasts. Some of his charts are still used, even almost 200 years after he produced them. However, Beaufort's even more important achievements are the invention of the Beaufort wind scale, which today is still used worldwide, and the usage of the Beaufort weather notation code, which after several modifications, later became the basis for modern-day meteorology codes.

See also Cartography; Hydrogeology; Wave motions