a note of clyimalogical normals - wmo-208

7/27/2019 A Note of Clyimalogical Normals - WMO-208

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WORLD METEOROLOGICAL ORGANIZATION

TECHNICAL NOTE No. 84

A NOTE ONCLIMATOLOGICAL NORMALSR e p o r t of a w ork ing g roup of the Commis s ion for Climatology

prepared by P. J A G A N N A T H A N , chairman - R. A R L R Y -H. T E N K A T E - M. V. Z A V A R I N A

W M O - N o . 2 0 8 . T P . 1 0 8etar ia t of the World Meteorological Organizat ion - G e n e v a - Sw i tze r land
http://wmo-no.208.tp.108/http://wmo-no.208.tp.108/


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THE WMO

The World Meteorologica l Organiza t ion (WMO) is a specia l ized agency of the Uni tedNa t ions o f which 125 Sta tes and Terr i tor ies are Members.I t was created :

to fac i l ita te in terna t ion al co-opera t ion in the establ i shm ent of ne tw ork s of s ta t i ons andcent res to provide meteorologica l services and observat ions, to p rom ote t he e s t ab li shment an d ma in t enan ce of Sys t ems for t he r ap id exchang e ofme teoro log i ca l i n fo rma t ion , t o p r o m o t e standardizatiou of meteorologica l observat ions and ensure t h e nniformpub l i ca t i on o f obse rva t i ons and s t a t i s t i c s , to fu r the r t he app l i ca t i on of me teoro logy t o av i a t i on , sh ipp ing , ag r i cu l t u re , and otherhuman ac t i v i t i c s , to enco urage research and t ra inin g in meteoro logy.T h e machinery of the Organiza t ion consists of the following bod ie s .T h e World Meteorological Congress, th e suprme body o f t he Organ iza t i on . b r ingstoge the r t he delegates of ail Members once every four years to dtermine gnerai policies forth e fulfilment of the purposes of t he Organ iza t i on , t o adop t Techn ica l Rgulations r e l a t i ngto internat ional meteorologica l practicc and to dtermine t h e W M O p r o g r a m m e .T h e Executive Committee i s composed of 21 di rec tors of na t ional meteorologica l servicesan d meets at least once a year to conduct the activities of t he Organ iza t i on and t o implementth e dcisions t aken by i t s Members in Congress , to s tudy and make r e c o m m e n d a t i o n s o nmatters affecting i n t e rna t i ona l me teoro logy and t he opration of meteorologica l services.The s ix Rgional Associations (f r ioa , As i a , Sou th Amer i ca , Nor th and Cen t ra l Amer i ca ,Sou th -West Pac i f i c and Europe ) , which are composed of Mcmber G o v e r n m c n t s , co -o rd ina t emeteorologica l ac t ivi ty wi thin the i r respect ive rgions and examine from t h e rgional po in tof view ail quest ions referred to them.T h e eight Technical Commissions composed of exper ts designated by Members a reresponsible for s tudying the spcial technica l branches re la ted to meteorological o b s e r v a t i o n ,ana lys i s , forecasting and research as well as to the appl ica t ions of meteo rology . T echn ica lCommiss ions bave been established fo r synop t i c me teoro logy , c l ima to logy , i n s t rument s andme thods o f obse rva t i on , a e ro logy , a e ronau t i ca l me teoro logy , ag r i cu l t u ra l me teoro logy ,hydromeleorology and mar i t ime me teoro logy .T h e Secrtariat, located a t G e n e v a , Swilzerland, i s composed of an internat ional sc ient i f ic ,technica l and administ ra t ive staff under the direction of th e S c c r e t a r y - G e n c r a l . I t u u d e r t a k e stechnica l s tudies , i s responsible for the numerous technica l assistance and other t e chn i ca lco-opera t ion projec ts in meteorology throughout the world a imed a t con t r i bu l i ng t o conomiedevelopmcnt of the countr ies concerned. I t also publishes specia l ized technica l notes , guides,manua l s and repor t s and i n gnerai acts as the link between the meteorologica l services of thewor ld . The Secrtariat works in close collaboration with t he Uni t ed Na t ions and o the rspecia l ized agencies.


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WORLD METEOROLOGICAL ORGA NIZATION

TECHNICAL NOTE No. 84

A NOTE ONCLMATOLOGICAL NORMALSR e p o r t of a working g r o u p of the Commis s ion for Cl imato logy

prepared by P. J A G A N N A T H A N , chairman - R. A R L R Y -H. T E N K A T E - M. V. Z A V A R I N A

Price : Sw . fr. 4.

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c^/^xN 0 T E

T h e dsignations employed and the prsentation of the nia ter ia l in this publ icat ion do notimply the expre s s ion of any opinion wha t soeve r on the pa r t of t he Secrtariat of the Wor ldMeteorologica l Organiza t ion concerning th e lgal s t a tus of any count ry or t e r r i t ory or of i t sauthor i t i e s , or conce rning the dlimitation of i ts f ront icrs .


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III

TABLE OF CONTENTSPage

Forevord VSummary (English, French, Russian, Spanish) VII1. Introduction 12. The prsentation of climatological data 33. The nature of climatological time sries 44. The stability of normals5. "Standard length of record" and "rfrence period" 66. The rfrence period vis--vis the purpose of normals 87. The influence of climatic fluctuations on rfrence period ... 98. Review of results 109. Short-period averages and "adjusted normals" 1410. Statistical parameters to be mapped in climatic atlases 1511. Concluding remarks 15List of rfrences 17


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VII

SUMMARY

The problem of fixing the optimum length of record for stable climatic statistics is essentially a statistical one and could be solved if thenature of the climatic time-series vere knovn. The length of record available,the homogeneity of the data, the variability of the climatic lments and aboveail the nature and extent of climatic fluctuations hve been the obstacles toa satisfactory solution of this problem.henever the heterogeneity in the climatic record is due to changesin station location, instrument exposure, observing standards or instrumentation, it should be eliminated as far as possible and only the resulting sries

treated as the climatological time-series. However, non-randomness in the sriesdue to genuine climatic fluctuations, inasmuch as such fluctuations are part andparcel of climate, should be incorporated in the derived climatic statistics.It is very difficult to specify a uniform period to use as a rfrence period for ail the lments vhich can be adequately reprsentative for thewhole vorld. It vould be dsirable if monthly and annual climatic statisticscould be compiled for every aecade uniformly for ail countries. Thse data couldbe treated as synoptic for purposes of comparison. Thse dcade statistics couldbe combined according to the requirements of individual research projects. Theclimatic statistics required for CLIMAT reports should continue to refer to the30-year rfrence periods, 190 1-30, 1931-60, etc.Climatic sries should be reconstructed as far back as possible by

rfrence to climatological data of other stations in the same homoclimaticzones. Por studies in climatic fluctuations and for the prparation of climaticatlases, it is dsirable to use such reconstructed sries.Mean maps are usually published in climatic atlases , but other fre-quency parameters vhich could provide valuable auxiliary information should alsobe published.


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VIII

RESUME

La dtermination de la dure optimale des relevs d'observationpour l'tablissement de statistiques climatiques stables est un problme essentiellement statistique qui pourrait tre rsolu si l'on connaissait la naturedes sries chronologiques climatiques. La priode pour laquelle on dispose derelevs d'observation, l'homognit des donnes, la variabilit des lmentsclimatiques et surtout la nature et l'ampleur des fluctuations climatiques ontt autant d'obstacles s'opposant la solution satisfaisante de ce problme.Chaque fois que l'htrognit des relevs climatologiques rsultede modifications apportes l'emplacement des stations, l'exposition des instruments, aux pratiques d'observation ou aux types d'instruments utiliss, elledevrait tre limine dans toute la mesure possible, et seules les sries ainsiobtenues devraient tre traites comme sries chronologiques climatiques. Toutefois, des variations de caractre non alatoire, releves dans les sries, etqui rsultent de relles fluctuations climatiques, devraient tre incorporesdans les statistiques climatiques drives de ces sries, dans la mesure o cesfluctuations font partie intgrante du climat.Il est trs difficile de spcifier une priode uniforme comme priodede rfrence utiliser pour tous les lments, qui soit suffisamment reprsentative pour l'ensemble du globe. Il serait souhaitable de pouvoir tablir danstous les pays, et sur une base uniforme, des statistiques climatiques mensuelles

et annuelles pour chaque dcennie. Aux fins de comparaison, ces donnes pourraient tre traites comme des donnes synoptiques. Ces statistiques dcennalespourraient tre combines selon les besoins particuliers de chaque projet derecherche. Il conviendrait que les statistiques climatiques destines aux messages CLIMAT continuent avoir trait aux priodes trentenaires de rfrence 1901-1930, 1931-1960, etc.Les sries climatiques devraient tre reconstitues aussi loin enarrire que possible par rfrence aux donnes climatologiques des autres stations situes dans les mmes zones homoclimatiques. Pour l'tude des fluctuationsclimatiques, ainsi que pour l'laboration d'atlas climatiques, il est souhaitabled'utiliser des sries reconstitues de ce genre.Les atlas climatiques comportent gnralement des cartes de moy ennes,mais il conviendrait de publier galement d'autres paramtres de frquence quipourraient apporter de prcieux renseignements complmentaires.


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IX

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RESUMEN

El problema de determinar la longitud dptima de los registros enlos que se han de fundar los datos climticos estadisticos es principalmentede carcter estadistico tambie'n y podria resolverse si se conocieran las caracteristicas de las sries climticas. La longitud de los registros disponibles,la homogeneidad de los dat os, la variabilidad de los elementos climticos ysobre todo la naturaleza y magnitud de las fluctuaciones climticas son los obs-tculos que se han opuesto a la solucidn satisfactoria de este problema.Siempre que la heterogeneidad de los registros climticos se deba a

los cambios de emplazamiento de la estacidn, a la instalacidn de los instrumentes, a los procedimientos de observacidn o a las caracteristicas instrumentales,debe eliminarse dicha heterogeneidad y solo las sries corregidas deben serconsideradas sries climatoldgicas. Sin embargo, las variaciones no aleatoriasde las sries, debidas a las verdaderas fluctuaciones climaticasj deben ser in-corporadas en los datos estadisticos rsultantes, siempre que dichas fluctuaciones sean parte del clima.Es muy dificil especificar la longitud del periodo uniforme que hayque utilizar como referencia para todos los elementos reprsentatives del mundo.Sria preferible elaborar datos estadisticos mensuales y anuales para cada de-cenio y con carcter uniforme en todos los paises. Estos datos pueden ser con-siderados como datos sindpticos para los efectos de comparacidn. Los datos estadisticos de cada decenio podrian adaptarse a las necesidades de cada uno de

los proyectos de investigacidn. Los datos climticos estadisticos requeridospara los informes CLIMAT podrian continuar refirindose a los periodos de 30aos, es decir , 190 1-1930 , 1931-196 0, etc.Se deben reconstruir las sries climticas, llegando hasta las fe -chas mas antiguas que se pueda, refirindose a los datos climatoldgicos deotras estaciones que pertenezean a las mismas zonas bioclimticas. En los es -tudios de las fluctuaciones climticas y en la preparacidn de atlas climticoses conveniente utilizar dichas sries reconstruidas.En los atlas climticos se publican habitualmente mapas de los va-lores medios de ciertos elementos. Se deben publicar tambie'n otros parmetrosde frecuencia que contribuyan a suministrar informacidn auxiliar util.


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A NOTE ON CLIMATOLOGICAL NORMALS

1. INTRODUCTIONThe problem of the length of the rfrence period necessary for thecalculation of mean climatological values, in viev of its practical importancein the various fields , has engaged the attention of climatologists for a longtime. At many international gatherings, recommendations hve been put forwardfor the prparation of multi-annual means of climatic lments (vide CE, Vienna1873, Resolution 2 0 ; CMI, Upsala 1894, Resolution 2; CD, Varsaw 1935, Resolution 111; CCI, Toronto 1947, Resolutions 13 and 1 4) . At the Warsav confrencethe period 1901-1930 vas recommended for vorld-vide establishment of normals

of climatic lments. In 1956, WMO recommended the use of the most rcent avail-able period of 30 years, starting on 1 January of a year ending vith the digit 1(for example 1921-1950), and that thse standard normals should be recomputedeach dcade, i.e. at the end of i960, 1970, etc. Thse dcisions hve been crit-ically examined at each of the three sessions of the Commission for Climatology,at the sessions of rgional associations, in vorking groups and in several articles. The difficulties encountered and the diffrences of opinion that hve re-sulted hve essentially been due to the realization that the whole Earth hasbeen experiencing a climatic change vhich has a diffrent character in diffrentparts of the world. Further, the large variety of purposes for vhich such long-term averages hve been used has demanded diffrent orders of stability ofthse averages.The failure to evolve an internationally acceptable solution hasevoked considrable concern, and studies hve been intensified in several coun-tries. Although the multi-annual averages of climatic lments are used for avide variety of purposes, they can be broadly grouped into tvo catgories.In one class of problem, vhat matters is not so much the absolutevalues of the averages, but rather the relative values the diffrence orrelationships of the values at diffrent points or parts of the area under considration. A fev examples of this type are the relative climates of coastalandinland districts; valleys and slopes of hills; the diffrent aspects of hills;and rural and urban environments.Second, there are problems vhich call for a sufficient degree ofabsolute accuracy in the values used. This is the cas e, for ex ample, vith the

compilation of climatic atlases. Vhen climatological data are to be used forthe design and construction of major engineering vorks such as dams and canals,vhich hve to last for at least a century, one vill hve to vork on probabili-ties. In addition to serving many such practical purposes, thse climatologicalstatistics are the basis on vhich a satisfactory theory of climate can be built.Though the problem is essentially scientific it has not, oving tothe many practical difficulties, been satis factorily solved. First and fore-most among thse is the unavailability of the required length of continuous andhomogeneous data in respect of ail the relevant lments. Since the year-to-year variations of the diffrent lments are diff rent, the length of the


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2 CLIMATOLOGICAL NORMALS

sries necessary to calculate stable values of the statistics will also vary.The prsence of inhomogeneity in the available data, and also of non-random-ness in the climatological time-series due to climatic fluctuations, has posedformidable problems.As a universally acceptable solution has not been found, there ex-ists a considrable diversity of practice in diffrent countries. This has na-turally given rise to discrepancies betveen similar investigations carried outin diffrent countries, thus hampering the development of climatic thories.If the problem is to be tackled from the fundamentals, it will beappropriate to define our conceptions of the diffrent terms. Ve should firstbe clear as to what ve connote by such terms as "climate" and "climatologicalnormal", and also as to their need.Any particular locality or rgion expriences a variety of veatherconditions from moment to moment, day to day, month to month and year to year.The gnerai atmospheric circulation (resulting from the multitude of processes

converting nergies in the atmosphre) and the local modifications dterminethe "climate". Further, climate has geographical extent, and this important dimension should not be forgotten. The influences, inter-relationships andinteractions of the various processes are very complex and no analytical quantitative treatment of ail the causes underlying climate is yet available.group property of the complex, comprising individual veather events and themeteorological lments characterizing them, their sequential character, theirinter-relationships and the geographical pattern, is vhat ve mean by climate.To get a true picture of climate it is necessary to paint it in ail its colours,the constant variations of the veather and the changes of the seasons.A satisfactory spcification of the climate of a locality or rgioncalls for several statistical measures such as the mean, the range, the frequen-

cy vithin the various intervais and the sequential character of the several climatic lments vith their variations and the various veather types that go tomaKe up thse statistics.Among the important climatic lments are physical properties ofthe atmosphre such as vind, temprature, moisture-content and pressure; various phenomena observed vithin the atmosphre or at the surface of the Earthsuch as rainfall, snov, the amount of cloud, the chemical character of the atmosphre and prcipitation; and the duration of sunshine and radiation balancecomponents such as the amount of incoming and outgoing radiation. Besides thseve hve the derived climatic lments, especially those vhich are closely re-lated to the energy and moisture exchange processes. Ail meteorological datauseful for climatological purposes are climatological data. Elments observedat the diffrent meteorological stations are climatic lments. Thse stations

are classified as synoptic stations, climatological stations, agricultural meteorological stati ons, aeronautical meteorological stations and spcial stations,specified in WIO Technical Rgulations (1959) and amplified in chapter 3 of theVMC Guide to Climatological Practices (i960).Climatology has a dual rle to play. First, it should provide information, as accurately as the available observations varrant, about the stateand the behaviour of the atmosphre. Second, because of its great conomie importance to a vide range of human activities, it has to provide a correspondingvariety of information to meet the needs of specialized user s. Risks hve to beassessed for engineering design and construction, for agricultural purposes,and for health and human velfare. Another important use of climatological information is in veather forecasting.


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CLIMATOLOGICAL NORMALS 3

The main aim is to abstract, from the varied and rapidly changingveather squence, the underlying patterns that characterize the atmosphericenvironment for particular rgions and for the Earth as a vhole. Most important of ail is the study of dynamic climatology, vhich aims at the understand-ing of the gnerai circulation. Such an understanding can subsequently help inlong-range forecasting.

For ail thse purposes, the climatological data of the past villhve to serve as a guide.

2. THE PRESENTATION OF CLIMATOLOGICAL DATAOne of the major responsibilities of national meteorological Services is the prsentation of climatological information in forms that vill satisfy the user. To meet a large variety of demands, climatological tables andmaps hve to be published summarizing the Knowledge of climate in forms vhichdpend upon the particular climatic lments. Climatic atlases enable the ma-jority of users to obtain a broad picture of those aspects of climate vithvhich they are most concerned. For planning purposes and for the understandingof atmospheric processes, averages and relative frequencies over the range ofvariation of the various lments are required.The choice of climatic lments for vhich normals are to be pre-pared and the form in vhich they are presented dpend upon the application forvhich they are intended. Agriculture vas naturally one of the earliest activi-ties in vhich climatological data vere used extensively, and there are nov manyothers. Among them are various branches of engineering, architecture, planninggroups and other technical enterpriseso The private citizen, vhose requirementsrange from gnerai curiosity about the atmospheric environment and its vagariesto the more serious interest stimulated by home gardening, travel or health prob-

lems, is also an important user. Further, there are the various research pro-jects in biological, physical and social sciences in vhich climatic environmentplays an important rle, and for vhich climatological data are required in avariety of forms. In particular climatological data are of fundamental value asfeedback material in meteorological research.

Some users can be satisfied by gnerai reports, vhich are periodi-cally published in the nevspapers. Most of them, however, require some interprtation of data to meet their particular problems. Engineers dtaling vithheating and air conditioning, highvay maintenance, vater supply, drainage,house construction and city planning need climatological tables and brief descriptions of practical value relating to major centres of population. For planning purposes in fields of activity vhere climatic environment plays a signifi-cant rle, as also for the purpose of understanding atmospheric processes, therelative incidence of the diffrent values over the range of variations of thelments vill be required. They are needed by the veather analyst in his day-to-day veather analysis. Similar monthly parameters are required for the revievof monthly veather. Hovever, modem requirements are much more sophisticatedand demand a variety of specialized summarizations and statistical parametersfor direct applications.

WMO indicated the need for the prparation of multi-annual statis-tics and of normals in its Technical Rgulations (M0, 1959). The prparationof CLIMAT reports is intended to give the synoptician, the reviever of the


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preceding month's weather and the analyst using the methods of dynamic climato-logy a means for evaluating the dviation of the value of a climatic lmentfor the current month from that for a rfrence period. Long-period averagesare intended for ail purposes of pure and applied climatology where currentclimatological data are to be compared vith what is to be regarded as a standard for international comparison and for use in planning.

The climatological normals are the climatological statistics wnichrepresent adequately, in ail their essential features , the "population" fromwhich they hve corne. Thse normals are needed for a variety of purposes inpure and applied climatology and serve as rfrence values.The stability of the statistic derived naturally dpends upon thesample size, which means the number of independent observations. As the climatological data are an ordered time-sequence of events occurring one after theother, the sample size is determined by the time interval. It is important tounderstand in this connexion that besides the "ave rage", which has been indi-

cated in the WMO Technical Rgulations (1959), there are other important statistics, for example standard dviation and other frequency characteristics,which are to be taken into considration for characterizing the normal featuresof the climatic lment. Further, as will be seen from the discussions whichfollow, longer-period statistics will also be required for some other purposes for example, planning.Anapolskaya and Gandin (1958), Lebedev (i960), Alekseev (1960,1962),Drozdov and Rubinstein (1962), Kuznetsova (1964), Sapoznikova (1964) and othershve worked out methods for obtaining thse characteristics which can be appliednot only to the data of individual stations but also to those of whole rgions,and which make it possible in many cases to obtain more accurate dtails of thediffrent characteristics.

3. THE NATURE OF CLIMATOLOGICAL TIME SERIESThe continuous record of any climatic lment or observations re-corded at intervais constitutes an ensemble of signais and noises, which areapproximately stationary but not strictly Gaussian. The aim is to extract thevarious signais and discriminate between them against the background of noise.Of the many statistical properties, the averages and auto-covariance functionor the power spectrum are generally the most useful for providing informationon the signais. In most cases the noise may be approximately a stationaryGaussian random process with zro mean, so that ail the relevant statisticalproperties could be obtained from the auto-covariance or power spectrum. Inmany cases the signais may also be approximately a stationary Gaussian random

process. For a proper understanding of the signais it is necessary to extractthe various non-random components from the noise or random component.In climatological time-series, the random component usually formsa large part, mixed up with some non-random components. The non-randomness maybe in the form of persistence, oscillation (periodic or aperiodic) trends orother forms, or perhaps some combination of several or ail of thse. Even ifthe variations are only random, in some cases the sries may appear to containfortuitious trends or cycles over a relatively brief period. Statistical testsapplied to this record may demonstrate the lack of significance of any trendor cycles. On the other hand, a relatively large trend or cycle that may beprsent may not reveal itself if the length of the record is rather short.


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Non-randomness can arise in a variety of vays. For example, thelocations of stations, instrumental exposure and observing standards are de-termined largely by operational requirements, and thse may hve changed fromtime to time oving to the increasing sophistication of requirements, of instruments, or of their applications. Thse in fact introduce inhomogeneities of record. Obviously, vhenever documented changes in station, location , instrumentsor procdures exist, the inhomogeneities introduced should be evaluated as faras possible and the records corrected.

Urbanization, landscaping projects, draining of swamps, construction of artificial lakes and rservoirs and many other man-made changes of local environment can create inhomogeneity in the climatological record. Thetransformation of natural land cover by soil conservation measures may influence climate on a rgional scale significantly. In industrial rgions the ex-tensive spread of air pollutants may affect the climate of the area signifi-cantly. In such cases, the inhomogeneity introduced should be eliminated as faras possible by a priori reasoning (in consultation with station inspection reports, etc.). If a particular station is still under the influence of certainof thse changes (for example urban area, artificial l akes, etc.), the earlierdata could be reconstructed as far as possible by the average mass curve method.In the Guide to Climatological Practices (WMO, 1960), it is recommended thatspcial attention should be given to the problem of homogeneity and that itmay be worthvhile to homogenize a long sries or combine several sries intoone. An exhaustive treatment of the methods for homogenizing climatologicaldata is given by Mitchell (1961 ) , Alisov, Drozdov and Rubinstein (1952) andDrozdov (1957).

The most important and unavoidable component of non-randomness inthe climatological time sries is that due to climatic fluctuations. For themost part, large-scale climatic fluctuations consist of non-linear variationsthat oscillate in an irregular long-period manner round a long-term climatological average. In a short sries, a long-period oscillation may show up as anillusory linear trend and if a diffrent period is take n, it may indicate adiffrent type of trend. Short records may reveal only the grossest sorts ofinhomogeneity, and many genuine ones may escape dtection.

4. THE STABILITY OF NORMALSBecause of sampling effect, the random "error" of normals based ona short period vould usually be relatively larger than that from a longer one.The magnitude of this error vill also dpend upon the variability of the lment under considration (for example the temprature values of a particularmonth are much less variable than those of rainfall). The prsence of non-ran

domness in the climatological time sries introduces systematic errors. If asystematic trend is involved, the systematic error increases with the lengthof the record period. The stability of any statistic derived vill naturallydpend on the nature and extent of non-randomness prsent in the sries aswell as on the volume of data utilized. Thus the study of non-randomness in theclimatological time sries helps in indicating the statistical significance ofthe various statistics and their confidence intervais (Sneyers, 1963).Some rcent investigations hve shovn that the combined effect ofrandom errors and those associated vith linear trend hve a broad minimum forperiods of the order of 20 to 30 years. Hovever, the various studies on climatic changes hve shovn their more or less fluctuating character. Further, due


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to the variations in the phase of fluctuations in diffrent parts of the world,a period which may be reprsentative for one place may be totally unrepresenta-tive for another. Thse considrations make one sceptical about finding a uni-versally uniform period yielding a stable normal.

5. "STANDARD LENGTH OF RECORD" AND "REFERENCE PERIOD"The optimum length of period is that which.when utilized for the prparation of statistics at any part of the climatological time sries, can serveas the best yardstick for comparison with subsequently observed features. Howcan one best dtermine the optimum length of record for yielding the requiredstatistic with an appropriate margin of safety? What amount of data of a givenaccuracy vould be required to attain a specified degree of accuracy for a par-ticular statistic? Any one period vhich could yield comparable statistics overwide areas of the world could be termed the "rfrence period".The problem is essentially statistical, and the statistical techniques evolved for the theory of sampling can give quite satisfactory resultsunder certain conditions. The question can be reduced to: "When does a frequencydistribution become essentially stable, so that adding a further year or yearsof observations would not add significantly to the resuit?" or, in other words:"When do the frequency characteristics such as average and standard dviationbecome essentially stable, so that the addition of further data would not changethe statistics significantly?" In symbolic forrn, if S is the statistic derived

on the basis of n terms of the sries, when is S ^s&S for any positive m?n + m^^ n J *

If the forrn of the frequency distribution is known, the probabilitythat any further value will lie within specified ranges can be indicated. For agreat many practical purposes, the values in a climatological time sries canbe treated on probability premises as if they had occurred by chance. Thus ifwe assume that the climatological time sries is composed of random componentsonly, i.e. that the values of the lment are distributed in the Gaussian form,then the mean and the standard dviation completely define the distribution andthe required probability of future values can be indicated.

We are interested in the probable variation of future values (of thestatistics) which represent the frequency distribution, namely the arithmeticalmean and the standard dviation; that is, we are interested in the standarderrors of the mean and the standard dviation.*Thus the larger the sries, the greater the confidence with whichfuture statistics can be estimated. The best statistic is that obtained by tak-ing ail the available data. Further, as the sampling error of normals based ona short period is relatively large compared with that based on a longer period,one might be tempted to use as long a period as possible and hence the longestavailable sries of data. However, the longer we make the standard period, thefewer will be the number of stations for which we can calculate the desirednormals directly from the data. An important point to bear in mind is that before

If a certain limit is set for the standard error for example, suppose thestandard error of the mean monthly temprature is set at 1 C we can testif the chosen normal period will fix the mean within this accuracy with aconfidence of 68 per cent. Alternatively, one can see how many years (n) ofobservations would be needed to give a standard dviation of /~nC.


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processing the climatological data it is necessary to homogenize the sries.The longer the period, the more difficult it is to maintain homogeneity. An -other factor is that, because of secular variations in climatological timesries, climatological statistics obtained from too long a period may not beadequately reprsentative of the contemporary climatic conditions.

Paucity of data can to some extent be minimized by reconstructionof the climatological time sries backwards , whenever comparable neighbouringstation data are available. This point will be discussed in a subsquent section.It is well knovn that, even though the random component usuallyforms a large part in the climatological time sries, there may still be somenon-random components mixed up to varying extents. If the non-randomness isdue to inhomogeneity introduced by changes of location, exposu re, instrumentation, etc., it could be estimated on a priori considrations from documentedrecords and eliminated beforehand. The important source of non-randomness isthat due to genuine fluctuations in climate, which embraces small-scale to

large-scale fluctuations of varying durations intermingled in a fashion soseemingly chaotic that it has not so far been possible to sort out the variouscomponents completely. Inasmuch as the climatic fluctuations are due to atmo-spheric or planetary causes they are an intgral part of the climate, and theclimatological statistic should therefore incorporate this feature as well.The climatological time sries may be in the form

where jA is the mean,^^. is the non-random component due to climatic fluctuations, and S-j. is the random* component. X- + c a n ^ e evaluax,ed and establishedby fitting polynomials of the appropriate degree, individually for each sries.

In the actual climatological time sries, we are interested to knowhow far the climatological statistics derived from a record of n years remainreprsentative during the test period of m years (n < m ) . What are the optimumvalues of n and m for the diffrent climatological statistics for the diffrent geographical locations?Considrable statistical knowledge is available as to how the nature of the frequency distribution or other frequency characteristics are mod-ified if the time sries involves any persistence or some other type of non-randomness. However, inasmuch as the physical causes of climatic fluctuationsare not understood, no idea can be had of the nature of such fluctuations indiffrent parts of the world. Whatever knowledge we hve is only from empiricalstudies of climatological time sries, and it is thus not possible to lay downany spcifie rule of procdure to deal with the problem. The only way appearsto be to study the frequency characteristics for diffrent lments over thediffrent parts of the globe. Particular attention should be given to the areaswhere the variation of the lment in question is large and also where climaticfluctuations hve been considrable.

From the statistical point of view.


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6. THE REFERENCE PERIOD VIS-A-VIS THE PURPOSE OF NORMALSThe diffrent purposes for which climatological statistics are re-quired put differing demands on the stability or the reliability of the statis

tics used. Inasmuch as thse statistics dpend on the volume and representative-ness of the data used in their drivation, the optimum length of record re-quired for a specified level of stability will dpend upon the lment concern-ed and also on the geographical features.In studies of local influences on climates for example the influences of urban or rural areas, sea coasts or inland a rea s, valleys or slopesof hills, etc. what is required is not so much the absolute value of thelments but rather the diffrence or relationships between such values at diffrent points. Comparative observations under the same synoptic situations willhve to be studied. The significance of the statistics derived will hve to bestatistically tested. Naturally, the differential behaviour under diffrentsynoptic situations, times of the day and seasons would hve to be estimated.A sufficient number of estimtes at each of the locations should be availableto provide statistical parameters whose relative magnitudes could be adequatelytested. The length of the record will obviously dpend upon the density of incidence of the particular phenomenon and its variability. In gnerai, for mostof the common climatic lments a period of 10 years would provide sufficientdata.Vhen the climatological normal is required to serve as a yardstickfor international comparison in synoptic analysis, comparability between syn-chronous features at the diffrent points over the area is necessary. For synoptic analysis on a monthly as well as a seasonal scale, what is essential iscomparability over wide areas, perhaps hemispherical or global. In some coun-

tries monthly maps are prepared on the basis of CLIMAT repo rts. Maps of anomalies regarded as synoptic (i.e. dviations from the multi-annual mean for eachmonth and year) are used for the slection of analogues for the purpose of long-range forecasting and/or studies in climatic fluctuations. Such dviations arealso published in "Monthly Climatic Data of the orld" (U.S. Veather Bureau).For thse purposes it is obviously necessary that the period should be as un i-form as possible and common for ail stations in the area. It should be longenough to eliminate local short-term variations (the 30-year periods, recommend-ed by VMO for normal s, appear to be appropriate) but it may happen that thislimination can only be achieved at the expense of the gnerai representative-ness of the period as a rfrence period, and it may thus lead to the ignoringof some additional information.

In pure and applied climatology and for analysis in dynamic climato-lgy> ^he actual climatological data will hve to be compared with those thatcould be regarded as standard; the anomalies and the relative probabilities inthe diffrent ranges of values of the individual lments hve to be taken intoaccount. For planning purposes in the various activities in which climatic en-vironment plays a significant rle, the normal climatic features are important.The climate of one place will need to be compared with that of another in orderto dtermine their relative suitability for several purposes. In connexion withthe design of major engineering works, climatic risks will hve to be assessed.Many structures hve to be built with a knowledge of extrme weather to ensureadquate safety for a specified amount of conomie risk. The maximum wind re-corded or anticipated in a locality has to be taken into account for construction of houses, hangars or bridges, the highest snow load for a roof, the heav-iest rain intensities for culvert design, etc. The probabilities of the various


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contingencies ha.ve to be estimated from the available observations. In thsecases ail available information at the station, as also at the neighbouringstations, should be used in order to drive the maximum benefit from the sta-tistics.In the prparation of climatic atlases it is essential that theclimatological statistic should hve a sufficiently high degree of accuracy.In this connexion a point worth remembering is that over a short period oftime there may exist a ngative corrlation between climatic variation in onepart of the globe and that in another: the relationship may hve an entirelydiffrent character over a diffrent period of time. Obviously, a picture ob-tained on the basis of such short sries cannot be reprsentative. It may appearthat maps prepared purely for national purposes need not conform to any inter-nationally adopted spcifications. However, inasmuch as maps may be used byneighbo\iring countries and by international agencies of many kinds, it is infact dsirable that national maps should be readily comparable with those ofneighbouring countries and should be capable of being joined together to pro

duce sub-regional and rgional maps. There is a plan for the prparation of aworld climatic atlas in the form of a collection of rgional maps supplementedby maps of marine areas and of the upper air. In this case it will be necessaryto use the maximum information recorded at the stations and also circumstantialvidence provided by other climatological stations in the saine homoclimaticzone. This vill mean that ail available data, those recorded at the stationsplus the reconstructed portions of the sries, will hve to be used. The lengthof the sries at the diffrent stations may not , however, be the same. Alisovet al. (1952) hve proved that climatological averages derived from periods ofover 50 years, even if they are not ail of equal lengths , vill be more mutuallycomparable than the averages for a single but shorter period; and they hvefurther proved that, where the distances between stations make conversion to along sries impossible, a long sries of observations and a shorter sries aremore comparable than two short synchronous sries. The data available in certainareas may be for a short period and conversion to longer sries impossible dueto the lack of comparable stations and in this case one has to be content to dothe best thing possible and await the building up of the climatological recordsin the course of time.

Studies of climatic fluctuations are fundamental in climatologicalresearch, providing the necessary insight into the nature of the volution ofclimate and hence throwing light in the physical processes involved. Everyavailable bit of record should be used. The sries should be as long as possible, restricted of course to the period for which the homogeneity of the datacould be evaluated. It should be remembered that even the reconstruction ofpast climates from historical, archeological and geological vidence has yieldedmaterial which has given valuable glimpses into the mechanism of climate.

7. THE INFLUENCE OF CLIMATIC FLUCTUATIONS ON REFERENCE PERIODIt is now well known that climate changes, and that there are fluctuations varying from the small scale, with periods of ux> to a century or so(so-called secular changes, established from recorded climatological observations), to the large-scale ones which take place over millions of years, forwhich vidence has corne from geological and other sources.Various types of climatic change are taking place throughout theworld. Climatic fluctuation is a phenomenon of formidable complexity, and inasmuch as it is part and parcel of climatology, the over-all theory of climate


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can scarcely ignore it. Naturally, it further complicates the problem of cli-matological normals as the solution of the rfrence period, and the optimumlength of the latter must dpend upon the nature of changes in the climate.The most striking feature revealed by studies in climatic change is the gneraiwarming in many parts of the vorld vhich started in the middle of the last cen-tury and vas maintained until about 194 0, at vhich time there appears to hvebeen a levelling or even a fall of temprature in some places. It vould appearthat the varming started in the high latitudes and vas slov and irregular atfirst, but became more rapid at the turn of the century, reaching a peak inthe thirties. The data also indicate that the rise has not been uniform or sym-metrical in respect of the ples. It has been least or nil in the middle latitudes of the southern hmisphre and greater in the higher latitudes of thenorthern hmisphre, especially in the areas bordering the Atlantic. The rain-fall picture is much more complicated. Hovever, the vidence is conclusive thatin the subtropical and tropical rgions there vas a sharp decrease of rainfallfrom a peak at the end of the last century to a minimum around 1930-1940 , andthereafter an increase. The decrease of rainfall vas accompanied by a contraction of the equatorial rain belt and a shortening of the vet seasons. A featureof the rcent return of vetter conditions has been the increase of tropicalcyclones. In the light of the many studies of pressure patterns and vind data,it is generally agreed that since the turn of the century until recently therehas been an increase in atmospheric activity, a greater exchange of air betveenthe Equator and the ples, and greater turbulence, i.e. an increase in the circulation of the atmosphre.

It has been vell established that climatic changes, especially theslover fluctuations that span several dcades, are vorld-vide in extent , andthat they arise primarily from changes in the large-scale components of thegnerai circulation. Thse in turn are dynamically inter-related over intercontinental distances, as shovs clearly vhen they are statistically correlated.Oving to climatic fluctuations the statistics based on 30 years oreven 50 years may not be so absolutely stable throughout the vorld as to betermed normal. Further, as climatic fluctuations vary in magnitude and phasein various parts of the vorld, a period vhich may be reprsentative at one placemay be totally unrepresentative at another unless the period is long enough tocontain intgral multiples of the diffrent significant periods. Summing up fromhis studies on climatic change, Lamb (1959) significantly remarked that "ourattitude to climatological normals must clearly change",

8. REVIEW 0P RESULTSAs previously stated, the problem of normals has been extensively

studied in many countries, particularly those vhere the climatic changes hvebeen spectacular.Rubinstein (1962), Kuznetsova (1964) and Shvec (1964) hve givenconsidrable attention to the problem of selecting the most rational periodfrom the point of viev of obtaining stable and mutually comparable values ofmeteorological lments leading to certain significant global studies.(a) Temprature. Ten-year monthly averages vary as much as 10 Cin some places betveen tvo dcades. The diffrence betveenthe averages of the monthly mean temprature determined for


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(d) Humidity. Data for 30 to 35 years provide sufficiently stable average values. The conversion of short sries of observations of absolute humidity to a longer period in a lovlandarea in the temperate zone is possible for distances of 250-300 km and in the case of relative humidity in summer fordistances up to 200 km. In vinter the relative humidity is sostable from one year to the next that even 20 - to 25-yearsries provide the necessary degree of accuracy.

(e) Vind. Mean vind speed, as well as maximum vind speed occur-ring once in ten, tventy or fifty yea rs, can be calculatedvith a sufficient degree of accuracy on the basis of 20 to 25years.(f) Radiation, Radiation characteristics, as well as characteristics of a number of other atmospheric phenomena, can becalculated on the basis of 25 to 30 year s.Similar studies hve been carried out by Berkes (1956), Steinhauser(i960) and Mitchell(1961), vho also concluded that 30-year averages are unstableand therefore poor indicators of climate. The fluctuate to such an extentthat they can be used as an index of climatic change rather than as a basis forclimatic maps. It va s, hovever, suggested (Berkes, 1956) that the existing climatic trend could best be kept up by choosing the preceding 30-year period atthe end of each dcade. This is especially important for agriculture.Pierson (i960) stated that time-series methods require lengthysample records for analysis. He emphasized the obvious instability of attemptsto extrapolate four- or eight-year apparent cycles into the future on the basisof data for only about 60 years .Shuh Chai Lee (1955) shoved that the period required to estimatethe average value of hydrological data to provide a certain desired accuracycan be expressed as N = P^t^/e^, where N is the number of years of record required, P the coefficient of variability, e the desired limit of accuracy andt the Student's t-value (limit of dviation of estimated mean expressed interms of standard dviation corresponding to a given percentage of probability).Benham (1955) shoved that the probable error of the mean (for a probability of50 per cent) is about 3 per cent of the long-term mean after a period of 10-15years, an order of accuracy at least as high as that attained in gauging. Heconcluded that the mean flov of most of the rivers could be reliably estimatedfrom a 15-year record.Enger (1956, 1959) and Beaumont (1957) studied the mean square er

ror and shoved that for temprature and prcipitation data (monthly as vell asannual) a 15- to 25-year period might be an optimum for the prdiction ofthse values one or more years ahead.De Portugal (i960) studied the data for Angola and concluded that:

(i) Five-year monthly and yearly averages are reprsentativefor atmospheric pressure, air temprature, relative humidity, surface vind speed, amount of cloud, sunshineand evaporation;


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( i i )

( i i i )


Ten-year monthly and yearly averages are reprsentativefor prcipitation at localities vhere the variabilitycoefficient is low;here the variability coefficient of prcipitation ishigh, the monthly and yearly averages are reprsentative only when they are obtained from very long sriesof observations (more than 30 years); and

(iv) Ten-year averages are not much more reprsentative thanfive-year ones. In Uganda a ten-year period was foundsufficient to show the characteristics of rainfall intropical are as, where the variability is lov.

The U.S. Army Air Force (1943) conducted a study of the length ofrecord needed to obtain satisfactory climatological summaries. An attempt wasmade to find the number of years needed to yield a relatively constant frequencydistribution (within 5 per cent) of the various meteorological lments signifi-cant for military aviation, such as visibility, cloudiness, cloud height, windspeed and persistence of rain. It was found that data for about seven to tenyears were needed for visibility, cloud and wind, while for prcipitation persistence the corresponding figure was about 20 yea rs. Landsberg and Jacobs(1951) hve indicated that the limit varies from lment to lment, from seasonto season and from rgion to rgion. From preliminary investigations they hveobtained the following provisional magnitudes.

APPROXIMATE NUMBER OF TEARS NEEDED TO OBTAINSTABLE FREQUENCY DISTRIBUTION

Climatic lment

TempratureHumidityCloudVisibilityPrcipitation

IslandsE.T.10345

25

T.5123

30

ShoroE.T.15645

30

T.8233

40

PlainsE.T.15585

40

T.10344

40

MountainsE.T.2510128

50

T.15666

50

Note : E.T. = extra-tropical, T. = tropical.Besides those mentioned above, investigations hve presumably beencarried out in several other countries.


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9. SHORT-PERIOD AVERAGES AND "ADJUSTED NORMALS"The value of any climatological statistic or any description ofclimate will dpend largely upon the value and extent of basic data utilized

in their compilation. However, for localities or areas vhere the observationalmaterial is insufficient for setting up tables and rliagrams, it may still bepossible to give some description on the basis of available data of the fewyears. In addition, vhenever data accumulate for at least five years, the short-period averages and a few other statistics such as extrmes should be preparedon the basis of the five-year data. As further data accumulate, the tablesshould be revised on the basis of additional five-year data periods.Monthly and annual climatological statistics for each ten-yearperiod (starting on 1 January of a year ending with the digit l) should alsobe prepared and published. Thse statistics can be used as such or in combi-nation with as many other ten-year period statistics as necessary, accordingto the requirements of particular investigations.We are frequently confronted with the situation of having only ashort record available for a locality in which we are interested, while a longer sries of data is available for another station in the same rgion. Owingto the fact that the climates of diffrent parts of a geographical rgion arerelated, the climatological information available at the latter station couldbe used to supplment that at the former. This property could be utilized:

(i) To check the relative consistency of the availableclimatological data at diffrent stations;(ii) To interpolate missing data in a recorded sries; and(iii) To reconstruct insufficiently long climatological sries

by referring to the data of a neighbouring comparablestation or stations for which a sufficiently long sriesis available.

The philosophy of this rests on the fact that either the diffrences or the ratios of relevant values of climatic lments are quasi-constant,and the relevant methods are described in dtail in several handbooks of cli-matology and also in Chapter 5 of the M0 Guide to Climatological Practices(i960). In areas where rfrence stations with sufficiently long records exist,the climatological data of stations with short sries can be enlarged; statistics derived from thse adjusted sries, which we may call "adjusted normals",should be used. Vherever such rfrence stations are not available, the statistics will obviously be limited by the available data. They are valuable as suchand can still be used within their limitations, stated in Section 1 above.

Inasmuch as the climatological time sries (made up of recordeddata plus the part reconstructed on the basis of information from neighbouringstations) contains more information than the recorded observations could givealone, multi-annual means based on long sries, even if they are not synchro-nous at diffrent stations, are more comparable than two shorter synchronoussries (Alisov, Drozdov and Rubinstein, 1952). As a corollary, it follows alsothat means based on a long sries at one station and a shorter sries at anotherstation are more comparable than two short synchronous sries at the two stations. This suggests that for the purpose of compiling climatic atlases it would


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be dsirable to use as long a period of data as possible after any necessaryreconstruction, even if the periods are not of the same duration or synchronousfor ail the stations.

10 . STATISTICAL PARAMETERS TO BE MAPPED IN CLIMATIC ATLASESUsually mean values of climatic lments are mapped in climatic at-lases. In addition, there are several frequency parameters which could providevaluable auxiliary information and supplment the maps of mean values. Thestandard dviation or coefficient of variability or range, as measures of dispersion of the lment, provide valuable information on the variability of thelment and thus indicate the degree of confidence which can be given to themean value s. This is particularly relevant when we consider mean atmosphericpressure maps. Thse mean pressure maps for calendar months may include two ormore distinct populations and may therefore yield rsultant circulation. As themean pressure map averages out the diffrent variations, it obscures the wind-iness. Maps could be added representing standard dviation of monthly and annu-al mean temprature and pressure as well as the coefficient of variability ofrainfall, vind and cloud amount, and indeed such maps hve been prepared by someServices. The extrme values of lments are use ful , as they indicate any co-herency existing in the incidence of certain magnitudes of extrmes in the diffrent parts of the rgion mapped. In using thse maps a point worth rememberingis that, in areas of peculiar orography such as hills, isolated values of extrmes may occur and attempts to draw isolines over the whole range may not beappropriate; such values could be indicated as spot values.

,, Distribution functions of some lments (including extrmes andn order valu es) can be fitted by various functions. Prom thse, probabilitylevels of occurrence can be readily derived and mapped. Thse are useful asdesign values. It is realized that manual processing of the data for thse pur-poses is very time-consuming and laborious; but wherever machine-processing fa-cilities are available, such parameters could be mapped easily.

11. CONCLUDING REMARKSThe problem of finding the optimum length of record to providestable climatological statistics is essentially statistical in nature ; it couldbe solved if the nature of the climatological time sries could be specified.However, there are a few practical difficulties which stand in the way of asatisfactory solution. First and foremost is the lack of sufficiently long homo-geneous records relating to the relevant lments. Further, the stability ofthe statistics dpends upon the variability of the lment; a very variable onewill require a larger volume of data than one which is less so. Climatic fluc

tuations of varying intensifies and durations hve corne to light. The fluctuations vary in magnitude and phase in various parts of the world. The severalfluctuations are intermingled in a seemingly chaotic manner so that it has notso far been possible to sort out the various components completely. Owing tothe climatic fluctuations, the statistics based on a specified period may notbe of sufficient absolute stability throughout the wrld to be termed normal.Further, a period which may be reprsentative for one place may be totally un-representative for another, unless the period is long enough to contain intgralmultiples of the diffrent significant periods.


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The average is not considered the only climatological statistic,and to characterize the climate other frequency parameters are also judged ne-cessary. The term "normal" should therefore be redefined to incorporate thisenlarged meaning.Studies hve shown that lments such as temprature, humidity andcloud amount, vhich are less variable, require a smaller number of years ofdata than prcipitation, vhich is much more variable; stations in mountainousareas require a larger number of years of data than those in the plains. Stations in higher latitudes of the northern hmisphre, vhich hve experiencedconsidrable fluctuations of climate during the past half century and more , require a larger number of years of observations than those vhere climatic fluctuations hve been much more subdued.It is very difficult to specify a uniform period that could be usedas a rfrence period for ail lments and vhich could be adequately reprsentative for the vorld as a vhole. It is dsirable for ail countries to compilemonthly and annual climatological statistics uniformly for every ten-yearperiod, at least for a reprsentative netvork of stations. Thse data could betreated as synoptic for the purpose of preparing ten-year maps of the globe ormajor portions thereof, and thse in turn could serve as valuable material forstudies in climatic changes. The statistics could be used as they vere or incombination vith as many ten-year statistics as might be required for any par-ticular pice of research.Inasmuch as the climatological information available at a placecould serve as a guide for a neighbouring location even though regular climatological records vere not available for the latter, climatological data-sriesshould be reconstructed vith rfrence to the climatological data of other stations in the same homoclimatic zone.The climatological statistics required for CLIMAT reports shouldcontinue to refer to the 30-year rfrence periods 1931-1960, etc. , as hitherto,because the global maps of anomalies prepared on the basis of such CLIMAT reports are very valuable for studies of long-range forecasting and climaticchanges.Climatological statistics should be prepared on the basis of reconstructed sries and only thse adjusted normals should be used for prparation of climatic atlases. It may happen that the data used in the prparationof the statistics are not ail synchronous nor of the same length; in spite ofthis fact the statistics derived from such long sries are more comparable thanthose derived from short sries, even if the latter are synchronous.

Vhenever climatological data are required for planning or assessingrisks for major engineering projects, or vhen they are required for studies inclimatic fluctuations, the maximum information available should be used.Besides the mean maps vhich are usually published in climatic atlases, there should be maps of other frequency parameters vhich could providevaluable auxiliary information.


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17

REFERENCES

Alekseev, G. A, i960: Graphoanalytical methods of dtermination of distributioncurve parameters and their reducing to long-sries record. Proceedings ofthe State Hydrological Institute, issue 73, Leningrad.Alekseev, G. A., 1962: Dtermination of standard parameters of logarithmic normal curve of distribution by three basic co-ordinates. Proceedings of SHI,issue 99 , Leningrad.Alisov, B. P., Drozdov 0. A. and Rubinstein, E. S., 1952 : Course in climatology,Gidrometeoizdat, Leningrad.

Anapolskaya, L. E. , and Gandin L. S., 1958: Methods of dtermination of computedwind velocities . Meteorologiya i gidrologiya (Meteorology and Hydrology),No. 10 , Leningrad.Beaumont, R. T., 19 57: A criterion for slection of length of record for movingarithmetic mean for hydrologie data. Trans. Amer. Geoph. Union 3 8, 2 pp.198-200.Benham, A. C , 1955: Proceedings of Rgional Techl. Confce. Vater ResourcesDevelopment, U.N.Berkes, Zoltan, 1956: Harminc evi torzsallagok, mint eghajlat - jalem zoszamertekek. IDO JARS, Budapest, 60(6) : 382-3 84.Conrad, V. and Pollak L. ., 1950: Methods in Climatology. Harvard UniversityPress, Cambridge, Massachusetts.De Portugal, J. B., i960: Climate Veather and Time with Tropics. Munitalp andFoundation Pr oceedings, Nairobi.Drozdov, 0. A. et al , 1957: Methods of climatological data processing, Gidrometeoizdat, Leningrad.Drozdov, 0. A. and Rubinstein, E. S., 1962: Results of the study of the climateof the U.S.S.R. Proceedings of the ail-Union Scientific Confrence on Meteorology, Vol. I. Gidrometeoizdat, Leningrad.Enger, Isadore, 1956: An empirical investigation of the period of time requiredto dtermine the normal daily maximum temprature. Master of Arts Thesis,American Univers]ty, Washington, D.C., pp. 69.Enger, Isadore, 1959: Optimum length of record for climatological estimtes oftemprature. Jour. Geoph. Resear., 64, 7, pp. 779-787.Grisollet, H., Guilmet, B. and Arlry R., 1962 : Climatologie - Mthodes et pratiques. Monographies de mtorologie, Gunthier-Villars et Cie, Paris.


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18 REFERENCES

Kagan, R. L., 1965: On the accuracy of dtermination of the areal average bypoint measurements data. Proceedings of the Main Geophysical Observatory,issue 175, Leningrad.

Kuznetsova, L. P., 1 964: Application of summary probability curve in processingdaily maximum prcipitation. Proceedings of the Main Geophysical Observa-tory, issue 16 2, Leningrad.Lamb, H. H., 1959: Our changing climate, past and prsent. Weather, Lond. XIV,10, pp. 299-318.Landsberg, H. E. and Jac obs, V. C.,1951: Applied Climatology. Compendium ofMeteorology, Ed. Thomas Malone, Amer. Met. Soc. pp. 976.Lebedev, A. N., i960: Diagram and charts for Computing climatic characteristicsof various intgral probability on the territory of the U.S.S.R. Gidrome-teoizdat, Leningrad.Mitchell, Jr. , J. Murray, 1961: The measurement of secular temprature changein the eastern United States. U.S. Dept. of Commerce, Weather Res. Pap.No. 43.Mitchell, Jr. , J. Murray, 1963: On world-vide pattern of secular tempraturechange. Proc. Rome Symp. on Climatic Changes of Climate, UNESCO Arid ZoneRes. XX, pp. 161-180.Pierson, Jr., Villard, 1960: On the use of time-series concepts and spectraland cross-spectral analysis in the study of long-range forecasting pro-blems. Jour. Mar. Res. 1 8, 1-3, pp. 112.Rubinstein, E. S., 1962: Personal communication to the vorking group.Sapoznikova, S. A., 1964: On the methods of characteristic of the climate ofthe U.S.S.R. Proceedings of the Main Geophysical Observatory, Leningrad.Schu Chai Le e, 1955: Proc. Rgional Techl. Confce. Water Resources Develop. N.N,Shvec, M. E., 1964: Application of the method of conscutive changes and for

calculation of prcipitation normals. Proceedings of the Main GeophysicalObservatory, Leningrad.Sneyers, R., 1963: Sur la dtermination de la stabilit des sries climatolo-giques. UNESCO, Recherches sur la zone aride, XX. Les changements de climat, Acte du Colloque de Rome, p. 38.Steinhauser, F., 1960: Sulle Oscillazioni climatiche in Europa. Geofis . emeteorol., 8, 5-6.U.S. Army Air Force HQ, 1943 : Study of length of record needed to obtain satis-factory climatic summaries for various meteorological lments. U.S. Aireather Service Tech. Rept. 105.U.S. Veather Bureau: Monthly Climatic Data for the orld. Sponsored by M0. U.S,Department of Commerce, eather Bureau, Asheville, N.C.


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REFERENCES 19

VMO, 1959: Technical Rgulations. Volume I. VMO - No. 49.BD.2, 2nd dition,Geneva .i960: Guide to Climatological Practices. VMO - No. 100.TP.44, Geneva.


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WMO TECHNICAL NOTES* N o . 1 Artificial inducement of prcipitation* N o . 2 Methods o f o b serv a t io n a t s eaPa r t I : Sea surface tempraturePar t I I : A i r temprature a n d h u m i d i t y , atmospheric p r e s s u r e , cloud heiglit,win d , r a in f a l l an d visibility* N o . 3 Meteorological aspects of aircraf t icing* N o . 4 E n e r g y from the wind* N o . 5 D iv er ses ex p r ien ces d e co mp a ra i so n d e r ad io so n d e s . Dr . L . M. Male t . . .* N o . 6 D iag ramm es a ro lo g iq u es . Dr . P . Dfrise* N o . 7 Rduction o f a tmo sp h er ic p r es su re (Prebminary r ep o r t o n p ro b lems in v o lv ed )* N o . 8 A tmo s p h er ic r ad ia t io n (Cu r r en t in v es t ig a t io n s an d p ro b lems) . Dr . W . L .G o d s o n* N o . 9 T ro p ica l c i r cu la t io n p a t te rn s . Dr . I I . Flohn* N o. 10 T he forecast ing f rom weather d a ta o f p o ta to bbght an d o th er p lan t d i seasesa n d p e s t s . P . M . A u s t i n Bourkc* N o . 11 T h e s t a n d a r d i z a t i o n o f t h e measurement o f ev ap o ra t io n as a cbmatic f ac to r .G . W . R o b e r t s o n* N o . 1 2 A tmo sp h er ics t ech n iq u es* N o. 13 A r t if icial contro l of clouds an d h y d ro meteo r s . L . Du fo u r - Ferg u so n Ha l l -F . H . L u d l a m - E . J . S m i t h* N o . 14 H o m o g n i t d u r s e a u e ur o p e n d e r a d i o s o n d a g e s. J . L u g e o n - P . A c k e r m a n n* N o . 1 5 T h e r e la t iv e accu rac y o f rawins an d co n to u r -measu red w in d s in r e la t io n top er fo rman ce c r i te r ia . W. L . G o d s o n* N o . 1 6 Su p e rad iab a t ic lapse r a te in th e u p p er a i r . W. L . Go d so n* N o . 1 7 N o tes on th e p ro b lem s of ca rg o v en t i la t io n . W . F . McDo n aldN o . 1 8 A v ia t io n asp ec ts o f mo u n ta in wav es . M. A . laka (reprinted 1967)* N o . 1 9 Ob se rv a t io n a l ch arac te r i s t i c s o f th e je t stream ( A s u r v e y o f t h e b t e r a t u r e ) .R . Berggren - W . J . G ib b s - C . W . N ewto n* N o . 2 0 T h e c l imato lo g ica l in v es t ig a t io n of soil t em p ra tu re . M ilton L . B l a nc . . . . \* N o . 2 1 M e a s u r e m e n t o f e v a p o r a t i o n , h u m i d i t y i n t h e biosphre an d so i l mo is tu r e . >N . E. Rid er j* N o . 2 2 P rep ar in g climatic d a t a for th e u se r . H . E . Landsberg* N o . 2 3 Meteo ro lo g y as ap p l ied to th e n av ig a t io n o f sh ip s . C . E . N . F r an k co m -M. Ro d ewald - J . J . Sch u le - N . A . L ieu ran ce

N o . 2 4 T u rb u len t d i ffu sio n in th e a tmo sp h re . C . H . B . P r ies t ley - R . A . McCo rmick -F . Pasq u i l lN o. 2 5 Des ig n o f h y d ro lo g ica l n e two rk s . Max A . Ko h le r IN o. 2 6 T ech n iq u es for su rv ey in g su r f ace-wate r r eso u rces . Ra y K . L in s ley /N o . 2 7 Use o f g ro u n d -b a sed r ad ar in meteo ro lo g y ( ex c lu d in g u p p er -w in d me asu re -m e n t s ) . J . P . H e n d e r s o n - R . L h e r m i t t e - A . Perlt V . D . R o c k n e y - N . P .Se l l i ck - R . F . J o n esN o . 28 Seaso nal pecu liar i t ie s of the temprature an d a tmo sp h er ic c i r cu la t io n rgimesin th e Arc t ic an d An ta r c t ic . P ro fesso r H . P . Po g o s janN o . 2 9 Up p er - a i r n e tw o rk r eq u i r em en ts f or numerical w e a t h e r p r d i c t i o n . A . E l i a s s e n- J . S . Sawy er - J . Smag o r in sk yN o . 30 Ra p p o r t p r l imin a i r e d u Gro u p e d e t r av a i l d e la Co mmiss io n d e m t o ro lo g iesy n o p t iq u e su r l es r se au x . J . B essem o u b n , p r s id e n t - H . M. De Jo n g - W . J . A .Ku ip er s - O . Lo n n q v is t - A . Meg en in e - R . Pne - P . D . T h o m p s o n - J . D .T o r r a n c eN o . 31 Rep r se n ta t io n s g r ap h iq u es en m to ro lo g ie . P . Dfrise - H . F l o h n - W . L .Go d so n - R . P n eN o . 32 Meteoro logical serv ice for aircraf t employed in ag r icu l tu r e an d fo r es t ry . P . M.A u s t i n B o u r k e - H . T . A s h t o n - M . A . Huberman - O . B . L e a n - W . J . M a a n -A . H . NagleN o . 33 Meteoro logica l aspe cts of the peacefu l uses of atomic en erg y . Par t I - Meteo ro lo g ica l asp ec ts o f th e sa f e ty an d lo ca t io n o f r eac to r p lan ts . P . J . Mead e . .N o . 3 4 T h e airflow o v er mo u n ta in s . P . Qu en ey - G . A . Co rb y - N . Gerbicr - H . K o s c h -mieder - J . Zierep ( r ep r in ted 1 9 6 7 )* N o . 35 T ech n iq u es fo r high-lcvel analysis and forecast ing of wind- and tempraturefields (Engbsh dition)N o . 35 T ech n iq u e s d ' an a l y se e t d e p r v is io n des ch am p s d e v en t e t d e tem p ra tu r e h au te a l t i tu d e ( d i t io n f r an a ise )

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N o . 36 Ozo n e o b serv a t io n s an d th e i r meteo ro lo g ica l ap p l ica t io n s . H . Ta b aN o . 37 A v ia t io n b a i l p ro b lem . Do n a ld S . Fo s te rN o . 38 T u rb u len ce in clear air and in cloud. J o s e p h C l o d m a nNo . 39 Ice fo rmat io n o n a i r c r a f t . R . F . J o n esN o . 4 0 Occu r r en ce an d fo r ecas t in g o f Ci r ro s t r a tu s c lo u d s . H erb e r t S . A p p lem an . .N o . 4 1 Cl imat ic asp ec ts of th e p o ss ib le es tab l i sh m en t o f th e J ap a n ese b ee t le in Eu ro p e .P . A u s t i n B o u r k eN o. 42 Fore cas t ing for forest f ire serv ices . J . A . T urn er - J . W . L il lywh ite - Z. Pies lakN o . 4 3 Meteo ro lo g ica l f ac to r s in f lu en c in g th e t r an sp o r t a n d r emo v al o f r ad io a c t iv ed b r i s . Ed i ted b y Dr . W. B leek erN o . 4 4 N u me r ica l me th o d s o f wea th er an a ly s is an d fo r ecas t in g . B . Bolin - E. M.Dobrisbman - K . H i n k e l m a n n - K . K n i g h t i n g - P . D . T h o m p s o nN o . 4 5 Per fo rma n ce r eq u i r em en ts o f ae ro lo g ica l in s t ru me n ts . J . S . Sawyer . . . .N o . 46 Me thod s of forecast ing t he s ta te of sea on th e basis of mete oro logic al d at a.J . J . S c h u l e - K . T e r a d a - H . Walden - G. VerploeghNo . 4 7 Prcipitation measuremcnts at sea. Review of the prsent s ta te o f th e p ro b lempreparcd by a working group of the Commission for Mar i t ime Meteoro logy .N o . 4 8 T h e prsent s ta tu s o f long-range forecast ing in th e world. J . M. Crad d o c k -H . Flobn - J . NamiasN o . 4 9 Rduction an d u se o f d a ta o b ta in ed b y TIROS meteo ro lo g ica l sa te l l i t e s . (P r e p a r c d b y t h e N a t i o n a l Weather Satel l i te Center of the U . S . Weatber B u r e a u )N o . 5 0 T h e p ro b lem o f th e p ro fess io n a l t r a in in g o f meteo ro lo g ica l p e r so n n e l o f ailgrades in the less-developed co u n t r ies . J . Van Mieg h emN o . 5 0 Le p ro b lme d e la f o rmat io n p ro fess io n n e lle d u p er so n n e l m to ro lo g iq u e d etous grades dan s les pay s insuff isamment d velopp s . J . Va n Mieghem . . .N o . 5 1 P ro tec t io n ag a in s t f ro s t d ama g e . M. L . B lan c - H . G es l in - I . A . H o lzb erg -B . Maso nN o . 5 2 A u t o m a t i c w e a t h e r s t a t i o n s . H . T r e u s s a r t - C . A . Kettering - M. Sa nuk i -S . P . Ven k i tesh waran - A . Man iN o . 5 2 S ta t io n s m to ro lo g iq u es au to ma t iq u e s . H . T r eu ssa r t - C . A . Ke t te r in g -M. San u k i - S . P . Ven k i tesh waran - A . Man iN o . 5 3 T h e effect o f wea th er an d c l imate u p o n th e keeping q ua li ty of fru it . . . .N o . 54 Mete oro logy and th e mig ra t io n o f Dsert Lo cu s ts . R . C. Ra in eyN o. 55 T he inf luence of weather condit ions on the occurrence of apple scab . J . J . Po s t -

C. C. A l l iso n - H . B u rc k h a rd t - T . F . P r eeceN o . 5 6 A s tu d y o f ag ro c l imato lo g y in scmi-arid and ar id zones of the Near E a s t .G . Per r in d e Brichambaut and C. C. WallnN o . 5 6 U n e t u d e d'agroclimatologie dans les zones ar ides et semi-ar ides du Proche-Or ien t . G . Per r in d e B r ich a mb au t e t C . C. Wal l nN o . 5 7 U t i l i za t io n o f a i r c r a ft m eteo ro lo g ica l r ep o r t s . P . K . Ro h an - H . M. d e Jo n g -S. N . Sen - S . SimplicioN o . 58 Tidal p h e n o m e n a in t h e u p p e r a t m o s p h r e . B . H a u r w i t zN o . 5 9 W i n d b r e a k s a n d s h e l t e r b e l t s . J . v a n Eimern - R . K a r s c h o n - L . A . R a z u m o v a -G . W . R o b e r t s o nN o . 6 0 Meteo ro lo g ica l so u n d in g s in th e u p p er a tm o sp h re . W. W . Kel lo g gN o . 6 1 N o te o n th e s tan d ard iz a t io n o f p r es su re rduction methods in the internationaln e two rk o f sy n o p t ic s ta t io n s . M. Schiiepp - F . W . B u r n e t t - K . N . R a o -A . R o u a u dN o . 6 2 P ro b le ms of t r o p ica l meteo ro lo g y . M. A . AlakaN o . 6 3 S i tes f or w in d -p o wer in s ta l la t io n s . B . D a v i d s o n - N . Gerb ie r - S . D . Pap ag ia -n ak is - P . J . Ri jk o o r tN o . 64 High-level forecast ing for turb ine-engined aircraf t oprations over Afr ica and theMid d le Eas t . P ro ceed in g s o f th e Jo in t ICAO/WMO Seminar, Cairo-Nicosia , 1961N o . 6 5 A su rv ey o f human b io meteo ro lo g y . Ed i ted b y F red er ick Sarg en t , I I , an dSolco W . TrompN o . 66 WMO-IUGG sy mp o s iu m o n r esear ch an d development asp ec ts o f lo n g - r an g efo recas t in g . B o u ld er , Co lo rad o , 1 9 64N o . 6 7 T h e prsent s i tu a t io n w i th r eg ard to th e ap p l ica t io n o f n u mer ica l meth o d s fo rr o u t i n e w e a t h e r prdiction an d p ro sp ec ts fo r th e fu tu r e . B o R. Dos - E . M.D o b r i s b m a n A . E l i a ss e n - K . H . H i n k e l m a n n - H . Ito F . G . Shuman

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N o . 6 8 M t o r o l o g i e s ! asp ec ts o f atmospheric r a d i o a c t i v i t y . E d i t e d b y W. B l e e k e r . Sw.fr. 18 .N o . 6 9 Meteo ro lo g y an d th e Dsert Lo cu s t . P ro ceed in g s o f th e WMO/FAO Semin ar o nMeteo ro lo g y an d th e Dsert L o c u s t . T e h r a n , 2 5 Novemb er-1 1 December 1963 Siv.fr. 30 .N o . 7 0 T h e c i r cu la t io n in th e s t r a t o sp h re , msosphre an d lo wer t h e r m o s p h r e .R . J . M u r g a t r o y d - F . K. Hare - B . W. B o v i l le - S . Tew eles - A . Ko c h an sk i Siv.fr. 18.N o . 7 1 S ta t i s t i ca l an a ly s i s an d p ro g n o s is in meteo ro lo g y . P ro ceed in g s o f th e WMOintcr-rcgional Semin a r o n S ta t i s t i ca l A n a ly s i s an d P ro g n o s is in M eteo ro lo g y .Par i s , 8 -2 0 Octo b er 1 9 6 2 Sw.fr. 4L N o . 7 2 T h e prparation and use of weather maps b y mar in er s Siv.fr. 18 .N o . 7 3 D a t a p r o cc s s in g i n m e t e o r o l o g y . P r o c e e di n g s o f t h e W M O / I U G G S y m p o s i u mo n Meteo ro lo g ica l Da ta P ro cess in g . B ru sse l s , 19 6 5 Sw.fr. 11 .No . 7 4 Data-processing b y m ach in e m eth o d s (R ep o r t o f th e CCI W o r k i n g G r o u p o nData-Proccssing b y Mach in e Meth o d s p r ep ared b y J . F . B o sen , ch a i rm an -P . E . K a m e n s k a j a - K . N . Kao - E . J . Sumner - T . W e r n e r Johannessen) Siv.fr. 5 .N o . 7 5 T h e u se o f sa te l l i t e p ic tu r es in wea th er a n a ly s i s an d fo r ecas t in g , b yR . K . A n d e r s o u - E . W . F e r g u s o n - V . J . Ol iv er ( A p p li c at io n s G r o u p , N a t i o n a lEnvironmcnlal Sate l l i t e Cenler o f th e En v i ro n men ta l Sc ien ce Serv icesA d m i n i s t r a t i o n ) Siv.fr. 24 .N o . 7 6 I n s t r u m e n t s a n d m e a s u r e m e n t s in h y d ro m e t e o r o l o g y . L e c t u r e s gi v e n a t t h eseco n d sess io n o f th e Co mmiss io n fo r Hy d ro meteo ro lo g y , War saw , 2 9 Sep -t ember -15 October 1964 Stv.fr. 7. N o . 7 7 Lo wer troposphre s o u n d i n g s (Report of a working group of the Commissionfor In s t ru m en t s an d Meth o d s o f Ob serv a t io n p r ep ared b y D . H . Pa ck , ch a i r

ma n - G . Cen a - A . Va len t i n - M. F . E . H in zp e te r - P . Vo c k ero th an d P . A .V o r o n t s o v ) Stv.fr. 5.N o . 7 8 (Rev ised v er s io n o f T ech n ica l N o te N o . 2 7 .) Use o f g ro u n d -b ased r a d a r inmeteo ro lo g y (excluding u p p er -w in d mcasuremeiits) (Rep o r t b y two wo rk in ggroups of the Co mmiss io n fo r In s t ru men ts an d Meth o d s o f Ob serv a t io n , p r e p ared b y R. F . J o n es , ch a i rman - J . P . H en d er so n - R . L h erm i t te - H . Mi t r a -A . Perlt - V . D . Ro ck n ey - N . P . Sellick an d r ev ised b y S . G . B ig le r , ch a i r m a n - H . N . Brann - K. L. S . Gunn - I . Imai - R . F . J o n es - L . S . Math u r -H . T r e u s s a rt ) Stv.fr. 14 .N o . 79 Climatic ch an g e (Rep o r t o f a wo rk in g g ro u p o f th e Co mmiss io n fo r Clima-to lo g y p r ep ared b y J . M. Mi tch e l l , J r . , ch a i rman - B . Dzerdzeevskii - I I . Flohn -W . L . llofmeyr - H . H . Lamb - K . N . Rao - C . C. Wal l n ) Sw.fr. 7.50N o . 8 0 U t i l i za t io n o f a i r c r a f t me teo ro lo g ica l r ep o r t s (A r ev ised dition o f Tech n ica lNo te No . 5 7 , p u b l i sh ed u n d er th e sa in e title) (Repor t of a working group ofthe Commission for Aeronautical Meteo ro lo g y p rep ared b y S . S imp b c io , ch a i r m a n , a n d V . Hoem) Stv.fr. 6.No . 8 1 Some me th o d s o f c l imato lo g ica l an a ly s i s . H . C. S . Thom Stv.fr. 6.N o . 8 2 A u to m at ic w ea th er s ta t io n s (P ro ceed in g s o f th e WMO T ech n ica l Confrenceo n A u t o m a t i c W e a t h e r S t a t i o n s , G e n e v a , 1 9 6 6 ) (In prparation) Sw.fr. 32 .No . 8 3 Mcasurcnient an d es t imat io n o f evaporation a n d vapotranspiration ( R e p o r tof the CIMO W o r k i n g G r o u p o n E v a p o r a t i o n Measurement, p r e p a r e d b yM . G a n g o p a d h y a y a , c h a i r m a n - G . Earl Harbeck, J r . - T o r J . N o r d e n s o n -M . H . O m a r - V . A . U r y v a e v ) Stv.fr. 15 .
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a note of clyimalogical normals - wmo-208

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