At all modern BAROGRAPHS Recording aneroids with continous meteorological stations charts; adopted for over 40 years by the French Meteorological Service. Standard equipment in the French THE PRECISION Navy. INSTRUMENTS OF THERMOGRAPHS Which can 'be combined with our barometers a nd hygrometers. These JULES RICHARD instr uments ore outstandingly sen­ sitive. provide a permanent answer HYGROGRAPHS Direct recording of air humidity on ruled charts. All types of indicators and recorders, including upper-air and dew-point instruments. SOLARIMETE RS Direct reading and recording ins­ truments for measuring the intensity of solar radiation. Pyrheliogrophs. ANEMOGRAPHS All types of a nemometers, includi ng " Popillon" electro-magnetic ins tru­ ments for recording instantaneous wind speed at a distance. RAINGAUGES All types of float, balance and syphon raingauges, both recording and non-recording. upon request lit\ IS I I OFFICERS OF THE WORLD METEOROLOGICAL ORGANIZATION President : Mr. A. VIAUT First Vice-President Dr. M. A. F . BARNETT Second Vice-President : Prof. Dr. H. AMOR IM FERREIRA EXECUTIVE COMMITTEE Mr. A. VIAUT Mr. F. X . R. DE SouzA Dr. A. NYBE RG Dr. M. A. F . BARNETT Mr. A. THOMSON Dr. F. vV. REICHELDERFER Prof. Dr. H. AMORIM FERREIRA Dr. C. DEL ROSARIO Mr. A. A. SoLorouKHINE Mr. J. RAVET Prof. Dr. Ing. J. LUGEON Sir GRAHAM SurroN Mr. S. BAsu Mr. L. DE AzcARRAGA Mr. M. F. TAHA TECHNICAL COMMISSION PRESIDENTS REGIONAL ASSOCIATION PRESIDENTS Aerology: Prof. Dr. J. VAN MIEGHEM Africa (I): Mr. J. RAVET Aeronautical Meteorology : Mr. A. H. N AGLE Asia (II) : Mr. S. BASU Agricultural Meteorology : Mr. J. J. BuRGOS South America (Ill) : Bibliography and Publications: Dr. M. MEZIN Mr. F. X . R. DE SouzA Climatology: Dr. C.\¥. THORNTHWAITE North and Central America (IV) : Instruments and Methods of Observation : Mr. A. THOMSON Mr. A. PERLAT South-\¥est Pacific (V) : Maritime Meteorology : Dr. C. DEL ROSARIO Cmdr. C. E. N. FRANKCOM Europe (VI): Prof. Dr. Ing. J. LUGEON Synoptic Meteorology : Prof. Dr. W. BLEEKER SECRETARIAT Secretary-Gene·ral: Mr. D. A. DAVIES Chief, Technical Division : Dr. K. LA NGLO Deputy Secretary-General: Mr. J. R. RIVET Chief, Administrative Division : Dr. H. SEBASTIAN THE PURPOSES OF THE WORLD METEOROLOGICAL ORGANIZATION (a) To facilitate world-wide co-operation (c) To promote standardization of meteo­ in the establishment of networks of rological observations and to ensure stations for the making of meteorolog­ the uniform publication of observ­ ical observations or other geophysical ations and statistics ; observations related to meteorology (d) To further the application of meteor­ and to promote the establishment and ology to aviation, shipping, agricul­ maintenance of meteorological centres ture, and other human activities ; and charged with the provision of meteor­ (e) To encourage research and training in ological services ; meteorology and to assist in co­ (b) To promote the establishment and ordinating the international aspects maintenance of systems for the rapid of such research and training." exchange of weather information ; From the Convention of the \¥orld Meteorological Organization, Article 2. THE CONSTITUENT BODIES OF THE ORGANIZATION (a) The World Meteorological Congress one of the six meteorological Regions which meets at least once every four of the world. They meet as often as years; necessary to ensure compliance with (b) The Executive Committee, which the policies of the Organization. meets at least once annually ; (d) Technical Commissions composed of (c) Regional Associations made up of experts in the various meteorological Members of the Organization the fields which meet at least once every networks of which lie in or extend into four years. THE SECRETARIAT The Secretariat of the Organization is located at Campagne Rigot, Avenue de la Paix, Geneva, Switzerland. W 0 R L D METEOROLOGICAL ORGANIZATION ~~~ ~~~~~[~~ JANUARY 1956 VOL. V NO. THE PICTURE ON THE COVER TABLE OF CONTENTS Page Man's interest in thunderstorms elates International G eo physica l Year 1957-58 . 2 back long before the first recorded essays in meteorology ; the fo lk-lore of many coun­ tries is rich in a llusions to the awe-inspiring A ctivities of the Technical Commissions . 10 nature of lightning. But as Gilbert, the celebrated English li brettist, so ably express­ Tech nical Assistance Programme . 12 eel it in th e light opera The Mikado, the scientist has a different attitude to natural phenomena: Second world comparison of radiosondes . 17 "But to him who's scientific, There is nothing that's terrific World Climatic Atlas 18 In the falling of a flight of thunderbolts." To meet a request from the International Telecommunications Union (ITU), the WMO Membership of WMO . .. .. .. ... 19 Secretariat has over the past three years been collecting information from a ll over the Activities of Regional Associations . 20 world on the number of thunderstorm clays which have been observed. These data have now been presented in a series of I 7 world Increased efforts to deve lop the arid lands . 21 maps giving the average number of thun­ derstorm days for each month, for the quar­ ters and for the whole year. These maps Collaboration with other international organiza - wi ll be published, together with a brief intro­ lions . 23 duction, at about the same time as this issue of the Bulletin ; a fu ller account of t he publication will be given in our next issue. Artificial control of clouds and hydrometeors 28 On examining the part of t he annual map which is reproduced on the cover, many will News an d Notes . • . • . 32 no doubt question the use of this particular projection ; the answer is that t his p rojec­ tion has been standardized b y the ITU for News from the WMO Secretariat . 34 ionospheric predictions. The general ques­ tion of projections for climatic maps was Reviews . reviewed recently at a meeting of the \•Vork­ . • . • . • . 38 ing Group on Climatic Atlases, a report of which will be found on p. IS. Calendar of coming events . 40 The purpose of the WMO B ulletin is to provide a summary of the work of the \~' or iel Meteorological Organization and of developments in international meteorology of interest to Members of the Organization and others concerned with the application of m eteorology to human activity. The WMO Bulletin is published quarterly in two separate editions : Engli sh and French. The price is I Swiss franc per copy, including postage. Annua l subscriptions ( 4 Swiss fra ncs) and a ll other correspondence a bout t he B ulletin should be addressed to the Secretary-General, World Meteorological Organization, Campagne Rigot, Avenue de la Paix, Geneva. Signed contributions do not necessa·rily represent the views of the Organization. WMO Bull eti n Jan uary 195S IN TERNATIONAL GEOPHYSI CAL YEAR 1957- 58 METEOROLOGICAL PROGRAMME Foreword The historical background of the International Geophysical Year (1957- 58) and some information about the programme were given in earlier articles in the vVMO Bulletin (Vol. IV, No. r , p. 6 and Vol. IV, No. 2, p. 52) by Prof. J. Van Mieghem, chairman of the vVMO Working Group on the International Geophysical Year. A report has now been prepared by Prof. Van Mieghem giving fuller d etails of the meteorological work to be undertak en . The full report is being distributed to meteorological services, but in view of the g reat importance of this progra mme a nd of the wide interest which it has aroused, it was decided to reproduce the main sections of the report in the Bulletin. PURPOSES OF THE IGY HE organization in 1957-58 of an the object of which was not clearly T International Geophysical Year specified. On the other hand, it ac­ (IGY) is intended to increase our cepted problems likely to be solv<:d by knowledge of the phenomena which means of a temporary increase can be observed in the tropical zone (r8 months) in the volume of obser­ and in the upper l ayers at all latitudes. vations. Meteorologists should direct their efforts firstly to the systematic exploration, Finally, the programme of meteor­ on a global scale, of the upper tropo­ ological observations has been based sphere and the stratosphere up to the on the problems included in the pro­ maximum bursting level of sounding gramme of investigations (see below). balloons. There is therefore an urgent It has been drawn up in such a manner need to fill the important gaps in the that meteorologists will possess at the upper-air network between the parallels end of the IGY a coherent set of basic of approximately 35° N and S and to data relating to the general circulation improve considerably the performance of the atmosphere. of vertical soundings. PROGRAMME OF INVESTIGATIONS GUIDING PRINCIPLES Improvements in the techniques of Top priority has been given to prob­ upper-air soundings, the increase in lems which are fundamentally world­ the number of radiosonde stations and wide in character, that is to say prob­ the extension of the upper-air network lems whose solution calls for effe ctive make it possible at present to carry international collaboration. out a daily three-dimensional analysis The Special Committee for the In­ of the earth's atmosphere over large ternational Geophysical Year (CSAG I) areas up to a level of about roo mb. has been guided in its choice of prob­ The progressive development of the lems by a desire to a void dispersal of upper-air network has been the main efforts and means. This is why it has factor contributing to the substantial declined to consider local or regional progress made in meteorology during questions of limited interest. the last t en years. Meteorologists have become more familiar with the It goes without saying that the com­ flow patterns associated with various mittee rejected any draft programme, synoptic situations.