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Fifty years ago ...

From WMO Bulletin 5 (1), January 1956



To meet a request from the International Telecommunications Union, the WMO Secretariat has over the past three years been collecting information from all over the world on the number of thunderstorm days which have been observed. These data have now been presented in a series of 17 world maps giving the average number of thunderstorm days for each month, for the quarters and for the whole year.

The main article in the January 1956 Bulletin concerned the International Geophysical Year  (IGY) 1957-58 (eight and a half pages). A report on the IGY had been prepared by Prof. J. Van Mieghem, chairman of the WMO Working Group on the International Geophysical Year. In view of the importance of the programme and the wide interest it had aroused, it was decided to reproduce the main sections of the report in the Bulletin. Other articles covered activities of the technical commissions, the Technical Assistance Programme, the second world comparison of radiosondes, the World Climatic Atlas, activities of the regional associations, increased efforts to develop the arid lands, and artificial control of clouds and hydrometeors. 

International Geophysical Year 1957-58

Meteorological Programme 

The organization of an IGY is intended to increase our knowledge of the phenomena which can be observed in the tropical zone and in the upper layers at all latitudes. Meteorologists should direct their efforts firstly to the systematic exploration, on a global scale, of the upper troposphere and the stratosphere up to the maximum bursting level of sounding balloons. There is therefore an urgent need to fill the important gaps in the upper-air network between the parallels of approximately 35°N and S and to improve considerably the performance of vertical soundings. 

Programme of investigations 

Improvements in the techniques of upper-air soundings, the increase in the number of radiosonde stations n the extension of the upper-air network make it possible at present to carry out a daily three-dimensional analysis of the Earth’s atmosphere over large areas up to a level of about 100 hPa. The progressive development of the upper-air network has been the main factor contributing to the substantial progress made in meteorology during the last 10 years. Meteorologists have become more familiar with the flow patterns associated with various synoptic situations. Certain aspects of the thermal and mechanical processes which maintain the general circulation of the atmosphere have also been revealed, such as the seasonal variations and the variations with height of the momentum and energy exchanges between zones of different latitudes. Nevertheless, many questions are still unsolved and for many others only a very unsatisfactory solution exits. The Special Committee for the International Geophysical Year (CSAGI) therefore recommends that the IGY investigations should be devoted to the large-scale physical, dynamic and thermodynamic processes of the general circulation ... 

(There followed a list of problems in synoptic and dynamic and physical meteorology.) 

Programme of observations 

… it should be pointed out that the term observing station here means any station carrying out synoptic observations of weather conditions. These stations include land sations located in low country, in the mountains, along the coasts and on islands, as well as stations on board weather ships and selected ships. 

To ensure that observational data are as comparable as possible, CSAGI recommends that the instruments used at stations which will be carrying out observations during the IGY should be checked without delay against national standards. Standardization of records and methods of observation is also desirable. Moreover, it is essential that WMO should organize in good time, well before the beginning of the IGY a worldwide comparison of the radiosondes in use. 

(There followed under “Synoptic and dynamic meteorology” a description of surface and upper-air observations and, under “Physical meteorology”, measurements of radiation, atmospheric ozone, atmospheric electricity, radio meteorology, composition of the air and precipitation and exceptional phenomena (noctilucent and mother-of-pearl clouds.) 

Network of observing stations 

The history of meteorological progress is inseparable from the history of the successive developments in the observing network. In spite of the considerable improvements which have been made during the past 10 years, the network is still inadequate because of the planetary nature of meteorological phenomena. The main effort must therefore be directed towards extending the network over the oceans and undeveloped areas. 

(There followed a description of the synoptic network, covering vertical cross-sections, requirements of the IGY synoptic network, gaps and deficiencies in the present synoptic network.) 

Action to be taken 

The need for upper-air data is so great that any plans for the establishment of new aerological stations in areas where the network is inadequate should be warmly encouraged. Where extensive gaps exist, it is better to increase the number of stations rather than increase the number of launchings.

In view of the well-known inadequacy of the aerological network over the oceans and the importance of the oceans, where most disturbances orignate, maximum advantage should be taken of all possibilities offered by large or small islands for the improvement of the aerological network. 

Meteorological Services of countries with whaling fleets should seek the cooperation of the whaling companies in order that surface weather observations may be made on board whaling ships during the 1957-58 whaling season and that meteorologists may accompany some of those ships in order to carry out the aerological soundings. 

It is recommended that automatic weather buoys be used in the southern seas where no surface synoptic observations are available. These buoys can transmit sea temperature, air temperature, pressure and the wind close to the sea surface. 

World Climatic Atlas 

Climatic maps are a means of presenting a summary of knowledge of the climte of a region in a form suitable for a wide variety of users, including meteorologists, agriculturists, hydrologists, civil engineers, biologists and those engaged in public transport. In a reasonably sized atlas it is impossible to present all the information required for specific purposes; some users are interested in detailed maps for small areas, others are satisfied with national maps and there is also a growing demand for regional maps. For certain investigations, world maps are required, as for example the world thunderstorm maps. 

At the second session of Congress, the need for an up-to-date World Climatic Atlas was recognized and it was felt that a certain degree of uniformity in national and regional atlases was desirable. 

The first task of the working group “set up to study these questions] was to prepare specifications of requirements to be met by national, subregional and regional climatic atlases. It was realized that for purely national purposes there is no imperative need to have national climatic maps prepared to a uniform, internationally adopted specification; such maps are however of use to neighbouring countries and to international agencies and should therefore be readily comparable with those of other countries and capable of being joined to them to produce subregional and regional maps. The specifications drawn up during the meeting were designed to serve two purposes, namely to provide guidance to meteorological services who are preparing or revising climatic maps, and to ensure that maps based on these specifications will provide reasonably uniform material for subregional and regional atlases. Points covered in the specifications are the map projection and scales, indication of topography and relief, isolines, layer tints, and the selection of stations. Details are given for maps of precipitation, screen temperature, humidity, atmospheric pressure, cloudiness and duration of bright sunshine, water balance and radiation. 

It was recommended that Members of WMO should be urged to prepare national maps and that regional associations should be asked to consider ways and means for compiling the corresponding regional sheets. For this purpose, diagrams showing how the work can be divided up into separate sheets on scales of 1 to 5, 10 and 20 million are being prepared. The projection recommended is such that, while distortion ofhte main land areas is kept to a minimum, the sheets can be joined together asrequreid for wall mounting. 

Climatic atlases should not be regarded as something static; however good they may be, they must be subject to revision both in the light of new data and of new ideas of physical and dynamic climatology, The first maps to be produced should be those which appear in orthodox climatic atlases—precipitation, temperature, etc.—but the target should be to produce maps of derived elements, for example of the radiation and water balance. These maps are in one sense the basic maps, for it is the radiation and water balance which determine the temperature and most other observed elements, than vice versa. Many users of climatic maps have already found that maps of evapotranspiration, water surplus, etc. are more suited to their needs than maps of some of the more usual climatic elements. 


The Kingdom of Cambodia became the 92nd Member of WMO on 8 November 1955. The United Kingdom of Libya became the 93rd Member of WMO on 28 January 1956. 

News and notes

Dr H. Theodor Hesselberg 

Dr Th. Hesselberg retired from his post of Director of the Norwegian Meteorological Service on 31 October 1955. During his 40 years in this position, the staff increasedfrom 15 to 310, an indication of the rapid development of this science and its many applications. 

Dr Hesselberg was the winner of the first IMO Prize in 1955. 

Dr Ragnar Fjörtoft 

Dr Hesselberg was succeeded by Dr R. Fjörtoft. Dr Fjörtoft had been Professor of theoretical meteorology at the University of Copenhagen from 1952 to 1955. Prior to that he worked for 12 years in the Forecasting Division of the Norwegian Meteorological Service and also spent 2.5 years in the USA, mainly at the Institute for Advanced Study, Princeton. His research was on theoretical meteorology, with special attention to numerical weather forecasting. 

WMO emblem 

A design for an emblem was submitted to all members of WMO for approval in September 1955. As the necessary majority of Members were in favour, it is now the official emblem of WMO. 



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