History of the ICA

With this new, thoroughly revised edition of Volume II of the International Cloud Atlas a key publication is once again made available for professional meteorologists as well as for a wide circle of interested amateurs. For meteorologists this is a fundamental handbook, for others a source of acquaintance with the spectacular world of clouds.

The present internationally adopted system of cloud classification is the result of work which started in the nineteenth century. The first studies on the topic were published by J. B. Lamarck (1802) and L. Howard (1803). The first attempt to use photography for cloud classification was made by H. Hildebrandsson (1879), in Uppsala, who prepared a cloud atlas of 16 photographs. The further development of this work, following the recommendation of an International Meteorological Conference which took place in Munich in 1891, resulted in the publication in 1896 of the first International Atlas, containing 28 coloured plates accompanied by definitions and descriptions of clouds and instructions on cloud observations in three languages (French, German, English). The first International Atlas, which was then adopted in almost all countries, was a great step forward in making internationally comparable cloud observations. This Atlas was reprinted in 1910, without substantial amendments. The subject of further refinement of cloud classification still remained to the fore, however, during the following decades. As a result the International Atlas of Clouds and Study of the Sky, Volume I, General Atlas was published in 1932 by the International Commission for the Study of Clouds. A modified edition of the same work appeared in 1939, under the title lnternational Atlas of Clouds and of Types of Skies, Volume I, General Atlas. The latter contained 174 plates: 101 cloud photographs taken from the ground and 22 from aeroplanes, and 51 photographs of types of sky. From those photographs. 31 were printed in two colours (grey and blue) to distinguish between the blue of the sky and the shadows of' the clouds. Each plate was accompanied by explanatory notes and a schematic drawing on the same scale as the photograph, showing the essential characteristics of the type of cloud.

When the World Meteorological Organization (WMO) came into being in 1951 in place of the non-governmental International Meteorological Organization, the First Meteorological Congress noted the need for a new International Cloud Atlas and referred the task to the Commission for Synoptic Meteorology. Within a relatively short time very substantial work was accomplished and the new Atlas was published in 1956 in two volumes: Volume I contained a descriptive and explanatory text on the whole range of hydrometeors (including clouds), lithometeors, photometeors and electrometeors; Volume II contained a collection of 224 plates (123 in black and white and 101 in colour) of photographs of clouds and of certain meteors. Each photograph in Volume II was accompanied by an explanatory text, to enable the pictures in Volume II to be understood without the detailed technical definitions and descriptions contained in Volume I.

The 1956 edition of Volume II has not been reprinted or revised until the preparation of the present edition. A revised version of Volume l, however, was published in 1975 under the title Manual on the Observation of Clouds and Other Meteors. ln the meantime there have been substantial advances in techniques of cloud photography and a growing requirement for more photographs taken at locations outside Europe.

ln 1981 a WMO Informal Planning Meeting on Volume II of the International Cloud Atlas drew up a plan for the preparation of a new edition. It recommended the deletion of 26 black-and-white plates and eight in colour, and their replacement by 41 new colour plates selected from a large number of photographs received from various countries. The section containing illustrations of certain meteors was also expanded by the addition of nine more plates. The legends for the new plates selected by the Informal Planning Meeting were edited by the chairman of the meeting, Mr. R. L. Holle, of the U.S. National Oceanic and Atmospheric Administration, and those for the new plates in the section on meteors by Mr. C. S. Broomfield, of the U.K. Meteorological Office.

Later it became apparent that many of the original photographs of the 1956 edition had deteriorated with time to an extent excluding the possibility of their inclusion in the new edition. Moreover, it was felt that the geographical distribution of the photographs was still somewhat restricted and that the balance between the various sections could be improved. With the approval of the president of the Commission for Basic Systems, it was therefore decided to revise the Atlas extensively, bearing in mind the urgent requirement for the new edition, and Mr. Holle kindly agreed to undertake this complex task, including the soliciting at short notice of new photographs from specialists. The final editorial work was carried out by the WMO Secretariat. The result of the work, the present Volume II of the International Cloud Atlas, contains 196 pages of photographs, 161 in colour and 35 in black and white. Each illustration is accompanied by an explanatory text.

The excellent work of the consultants and the authorization willingly given by all contributors for publication of photographs in both the original volume and this new edition are gratefully acknowledged. Particular thanks are due to the printer, whose painstaking work permitted much of the original material to be conserved and blended harmoniously with the new contributions.

It is felt that this new edition of the Atlas, besides being a most valuable reference work for meteorologists and those working in aviation, in agriculture and at sea, will also be a fascinating addition to the amateur's bookshelf.

(G.O.P. Obasi)

Secretary-General