23 March is World Meteorology Day. A day when there will be many scientific discourses on the science of the atmosphere and the weather. While not many adults may look up at the sky and marvel at the beauty of clouds as they drift up high, children will look up and imagine, in the continuously changing cloud shapes, everything from elephants to cotton candy! Perhaps few will make any links between the poems and paintings of this beauty with any form of scientific study.
While clouds are almost as old as the earth when it was formed, the science of clouds is much younger. Before the 19th century, the general understanding was that each cloud was unique, unclassifiable and in a state of temporary existence. Instead of strict descriptions clouds, were recorded by colour or individual interpretation. The scientific study of clouds may have said to have begun at the dawn of the nineteenth century, when a young man did more than admire the shapes of clouds, and set out to observe, study and devise a classification system for clouds. This was Luke Howard a London pharmacist and amateur, but ardent, sky gazer.
Luke Howard was born in London on 28 November 1772, the first child of a successful businessman. When he completed school Luke was apprenticed to a retail chemist, and went on to develop his own business, setting up a firm that manufactured pharmaceutical chemicals. While he ran his business, Luke also indulged his childhood fascination for nature, and especially the numerous facets of weather. He built a laboratory at home to observe, collect weather-related data and analyse this; he also maintained meticulous records of his observations.
In 1802 the modest young Luke made a presentation to a small gathering of young science-minded intellectuals in London who called themselves The Askesian Society. The lecture was titled On the Modification of Clouds (Modification referring to classification). In the talk, Howard proposed a common system for naming the recognisable forms of clouds. In order to enable the meteorologist to apply the key of analysis to the experience of others, as well as to record his own with brevity and precision, it may perhaps be allowable to introduce a methodical nomenclature, applicable to the various forms of suspended water, or, in other words, to the modification of cloud.
Howard proposed a common vocabulary to describe different forms of clouds. The proposed system used Latin names like those that were being used for plants and animals in the Linnaean system. Combining detailed observations with imagination Howard introduced three basic cloud types:
Cirrus (Latin for ‘a curl of hair’) which he described as “parallel, flexuous or diverging fabrics, extensible in any or all directions”.
Cumulus (meaning ‘heap’), which he described as “convex conical heaps, increasing upward from a horizontal base”.
Stratus (meaning ‘something spread’), which he described as “a widely extended, continuous, horizontal sheet, increasing from below”.
He combined these names to form four more cloud types:
Cirro-cumulus, which he described as “small, well-defined roundish masses, in close horizontal arrangement”; Cirro-stratus, which he described as “horizontal or slightly inclined masses, attenuated towards a part or the whole of their circumference, bent downward, or undulated, separate, or in groups consisting of small clouds having these characters”; Cumulostratus, which he described as “the cirrostratus blended with the cumulus, and either appearing intermixed with the heaps of the latter, or super-adding a widespread structure to its base” and Cumulo-cirro-stratus or Nimbus, which he called the rain cloud, “a cloud or system of clouds from which rain is falling”. He described it as “a horizontal sheet, above which the cirrus spreads, while the cumulus enters it laterally and from beneath”.
This was a historic lecture for many reasons. His classification brought a sense of order and understanding to a subject that had lacked coordinated thought. There were at the time no documented theories as to how pressure, temperature, rainfall and clouds might be related. Howard’s observations and classification marked the beginning of meteorology, a previously unrecognized area of natural science. The three families he proposed—Stratus, Cumulus and Cirrus , are today included as examples of the ten main cloud types – known as the cloud genera, which are defined in terms of their shapes, their altitudes and whether they are precipitation bearing. Howard’s simple, science-based system of classification was accepted by the international scientific community, and the terms that he coined are still used by the meteorological community across the world.
Howard was not just an observer and recorder, he was also skilled at painting skyscapes with clouds. He was however not adept at painting landscapes and people and a painter friend used to fill in these to complete the picture. He used these paintings to illustrate his talks and publications about cloud classification. Howard’s 32 page cloud book The Modifications of Clouds, published in 1803, is illustrated with his water colours.
Even as Luke Howard was studying clouds, for three decades he also kept daily recordings of temperature, rainfall, and atmospheric pressure in and around London. His comparison of the data allowed him to detect, describe, and analyse the fact that average temperatures are higher in cities than in the countryside. As he described it, the temperature of the city is not to be considered as that of the climate; it partakes too much of an artificial warmth, induced by its structure, by a crowded population, and the consumption of great quantities of fuel in fires. Through his observations Howard was the first to recognise the effect that urban areas have on local climate, many decades before the phenomenon of Urban Heat Islands became the hot topic that it is today.
He published his findings for his “fellow citizens” as volumes titled The Climate of London deduced from Meteorological Observations at different places in the Neighbourhood of the Metropolis in 1818 and 1820, followed by an extensive second edition in 1833. Howard thus became one of the pioneers of urban climate studies.
Luke Howard was elected a Fellow of the Royal Society on 8 March 1821 and joined the British (now Royal) Meteorological Society on 7 May 1850, only a month after the society was founded. He died in London on 21 March 1864.
As we look up at the clouds in the sky, let us remember the one who gave them names.
–Mamata
Millennial Matriarchs 