BhaH, 1984 MONTHLY WEATHER REVIEW 157
bility,. or frequency of its occurrence, P, is given by the equation?
where h and k are constants. If the law of probability does actually govern t.hc distribution of the velocities of the different winds, the graph of Figure 3 must conform to the above general equation. A convenient method of determinin this is by means of what is known as “arithmetic pro % abilitj paper,” whereon a robability curve, or curve of fre- quency, when plottei, will at pear as a straight 1ine.O The frequency of east an5 west component winrls of Werent s eeds as found by kite and pilot-balloon records has there P ore been replotted on probability pa er and
the result is shown in Figure 4. lie re-
markably closely along a strai ht line, the greatest cle- viation in observed frequency %eing 2.5 per cent, while the deviation in general is less than 1 per cent. articular route, therefore, we have experi- mental evi a ence that the probability of occurrence of an east or west wind component of given s eed may I>P
speeds. If this relat,ionship between the velocit,y of a
free-air wind and the probability of its occuimnce can be shown to hare general ap lication for other routes
of minds of different speeds when suficient (1at.a are at,
hand to determine the t.rend of tlie probability curve.
A plrliminary examination of free-air wind data for other parts of the counpj- indimbes the correctness crf
this h potheisis.
an increasing number of air niatil flights, tend to apyroadi more and moir closely the wiiids as found by kite and pilot balloon observa.tions. This is esuctly what we should expect if tlie act.unl winds (us would be disclosed from nn indefinite number of obstmntions), really do n r y in cw.cord t1.1ice wi t. ti the la.\+- of yrohuhility .
p e Pe-h’fl
The points
For this
redicted wit-h sui rising accuracy, by the I! aw of proha- {ility, from the o x seiretl frequency of winds of other
BS well, a powerful method is c P isclosed for the prediction
In & e present instance t,he winds, as determimd from
SUMMART AND COSCLUBIOKR
1. An extension of the a.ii:Llysis of air mail records t,o
coyer two consecutiivc -ye:i.rs of operation between New York and Chicago indic.at.es that the winds as deter- mined in the re-rious analysis from more limitred d a h
2. In general, the winds deterniined from an increasing number of flight records tend to conform more closely to the winds as found by kite and ilot balloon observa-
a.re substantial Y y correct.
determination of the wind P actor. tions. The tendency is articu P nrly evident in the
in general to be overned by the robability law, in which
frequency of a given wind speed when complete informa- tion is not at hand.
case a powerfu k method is disc P osed for predicting the
~~ ~ ~~~~
Merrlman. Maasfleld. Method of Least Equm. New York:,1915, p. 2.5 For a dfseussion of the wnstructlon and use of thls pap Storage to be Pro- vided in Impounding Reservoirs for Munldpal Water upply’’ by Allen Bamn. Trans. of Amer. Em. of Clvil E neers, vol. 77, pp. 1530-1687,19lrf also “The Element d Chanm in EanitstiOn,” byveorge C. Whlpple. J m . Franklln’Inst., rol. IR2, PP. a 7 4 , %am, 1016.
4. ,4n interesting improvement in the general per- formance of the air mail planes is revealed by an increase of several miles per hour in the average cruising speed. This is indicative of the type of improvement which may be expected in an air trans ortation service as experience in operation is accumulate fl . 5. In view of the importance of an accurate knowledge
of wincls alon routes where regular aircraft o erations
results emphasize again the urgent need for a material extension of aerologcal investigations to cover all parts of the country.
are likely to % e initiated in the near future, t % e above
.SS-/. 596. 2 (zS/)-@‘+-- -/’
RESULTS OF MEASUREMENTS OF SOLAR RADIATION AND ATMOSPHERIC TURBIDITY OVER THE ATLAN- TIC OCEAN AND IN ARGENTINA.-PRELIMINARY REPORT By Dr. FRANZ LINKE
Il’r;rnslaled from in:ninscript text in Qerman by W. W. Reed, Weather Washington, D. C., January 7,19241
1. Dada on, the e x edition..-April 5, 1923, departure
rival a t Buenos Aires; beginning of Ma.y to the begin- ning of July, journeys in Ar entina; July 15, departure from Buenos &res on the k n d m 6 t .q ; August 15, ar- rival at Hamburg.
2. 1?1s~~~~ments.-~nirersal actinoiiieter of Hartmann & Braun of Frankfort on the Main, made according to specinl plans with H red-glass filt.er having a thickness of
3.02 inm. (Scliott. F. 4512) and range of t,ransmissibility from 600 to 2,000 p ~. Incandescent-lamp photometer with sodium c.e.11 of Giint,lier & Tegetmeyer, Brunswick, with Wulf’s 1)ifila.r electrometer and condensers of Siemens & IInlske having capacity of 2, 0.5, and 0.1 microfarads. Blue scale for t.ho estimation of sk color (inisture of white and Prussian blue) issued t! y the Unesma, Leipzig. Portable aspirat.ion psychrometer of
R. Fuess, Steglitz. Previous to the departure from Hamburg, frequently in Argentina, and after tlic ret.mm from the expedition t.he act,inomoter WBS corn ared with :tn ihigstrom corn-
revised (1913) Smit.hsonian scale by W. Marten at Pots- clam. Unfortunately the condensers, which are neces- sary for incandescent-lamp radiation ineasurements with electrometciy ( alvanonieters .of rec1uisit.e sensitiveness
state of 1nsulat.ion in the Tropics, so that great difficult is met with in the work.
3. Jfeth.od,q of obsem.thn.- Measurements were made only when the sun was unquestionabl free of cloud and at every favorable time of the day. % hese were carried out more frequently in the mornings and evenings; during the midday hours long interruptions occurred. The apparatus for measuring radiation was exposed on shipboard on the roof of the pilot house on a table hav- ing Cardan’s method of suspension (swinging table). All observations were made b me. At each reading the
Observations of air pressure, temperature, and relative humidity were made several times daily. On the out- ward and on the return voyage when the sun was at its zenith position measurement was made of sky bright- ness for the spectrum range of the sodium cell (maximum sensitiveness about 360 pp.
The blue scale contained 8 color tones from white to ultramarine blue, and estimation was made to halves of the scale. No. 3 \vas white; No. 10, ultramarine blue.
from Hamburg on t K e General San Martin; May 2, ‘ar-
pensation pyrheliometer t. P iat had been ttcljusted to the
atre not practica % le on expeditions), gradually lose their
altitude of the sun WM (9 eterniined with the sextant.
158 MONTHLY WEATHER REVIEW MAEOH, 1924
The deepest blue (No. 9) was observed in La Quiaca at '9 If we assume with J. Hann that the total water content the boundary between Argentina and Bolivia, about of the atmosphere over a s uare meter of surface is on an average 2.38 or, as F. E. 9 owle computes i t in depth of 3,700 meters above sea levelT
4. Methods of calc&tion.-The air mass (m) through which radiation passed was determined, for the measured altitude of the sun, from Bemporad's table with reduc- tion to a pressure of 760 mm. The turbidity factor (T) was measured accordin to the extinction formula' de- veloped by me on the f asis of a solar constant value of 1.932, takmg into consideration the earth's solar distance. From the obscrvations with the actinometer and the photometer there were interpolated, as far as the observ- ations might permit, both the vdues for m= 1.0, 1.5, 2.0,
2.5, 3.0, 4.0, 5.0, 6.0, 8.0, and 10.0, and also, with good daily series, those for the different hours of the day. The interpolation was made graphically on the logarithmic paper of Schleicher & Schull, No. 3673 ST. K. For the zones and points designated in Table 1 meltn values wcre derived from these interpolated values in the usual way.
TABLE 1.-Radiation intensihy, turbidity, and sky color
- -.
I j .... ___!
j
i---- ____ ____ .- . .. . . ____
Dunkelm~ar 1 ___________
brgemtjna, cities I-. . ___, Argentina,mtrp a.--- 1.590 !
Andes 4 __________._____ _, Bolirianplatenu G......' 1
1.481
222 '
2.14 2.17
353
1.36 ,
i
1:46 1
mnr iii i 19.: I
9. 1
15.0 ; 14.2 I
18.0 I
6.0 1 3.0: 2 2 ;
0. R
4.7 s.7 5.7 L 7
6.9 6.5 7.1 8.0
8.0
a. 6
2.61
1. a 1.21
0.51
0.86 0.41
0.38
ao4 n. 50
a 21
1 Off CapeVerdeIslands. : La Plata and Mendozn. a PUar new Cordoba.
4 Pue& del Fuca, 2.700 metera. La Qui-, 3,WO meters.
5. Results o measirrements of totd rudiution.-Colurs
radiation values in gram calories per square centimet,er per minute for the zenith dist.nnce of the sun corres ond- ing to ni= 1 and m= 3; column 4 gives the turtic1it-j- factor for the solar altitude 19.3' (zenith distance, '70.7'). corresponding to m- 3, which is almost always reached in the Temperate Zone. Column 5 gives the mean absolute humidity (e) in mm. of vapor pressure; column 6, the blueness of the sky. It is noted how well the blue coloring runs opposite to the turbidity factor. However, in the, upper portion of the accompanying Figure 1, the turbidity factor and the absolute humiditr show no significant connection.
In the regions where the turbidity was evidently caused by dust and other dry particles (trockener Dunst) as on the Dunkelmera on account of the desert dust carried from the Sahara by the northeast trade wind, in the north Temperate Zone in the English Channel, and on the coasts of France and Spain on account of winds from the land, and in the cities of Argentina, the observa- tions show a degree of turbidity whch exceeds that cor-
:r!ttgdi%e turbidity factor .inmtwwa 0.0.47e .for Pacf
mz B imeter of vapor presmrs.
3 and 3 in d &le 1 give the means of the intmpolatecl
to the degree of humidity . In the remainin
I Meteorologische Zeitschrilt 1923 S. 161 If.
3 DuukeZmeer, th,e name give; to the portion of the .4tlantle Ocean between the Eqne tor and the Madeira Islands extending from the coast of Africa to 3Q0 west longltude .Wyrrr h'onccrsationcLrztkon .
- 2 38 water in cm., w =A then there results an increase in 10 9
the turbidity factor amounting to 0.20~. This agrees fairly well with a purely theoretical calculation in my first pn er on the turbidity factor,J in which on the basis
coefficients of dry air and of water vapor I found T,= 1 +O.lGw(formultw 8 and 10). Thus the influence of the water vapor contained in the air may be eliminated, and since for ideally pure air tho turbidit? factor is b~ definition equal to 1, the influence of the 'dry" turbidity (dust., smoke, salt, etc.) mtly be e3timated if we subtract from the observed turbidity factor the value 1 +O.l6w.
or 1+0.037e. The art of turbidity due to particles of dust, etc. (trockener %umt), thus uppew in column 7 of Table 1. In Table 2, I add some observations of the turbidity factor for central Europe in order to make a
comparison possible.
'raam 2.-Turbidity i n central Europe
of the : ata by F. E. Fowle relative to the transmission
Station
- . . __ - .... - - . .. . ._ - . . . . . ___I ___ :---I
Frankfort on the Main: mnr. '
Kolllerg:
Winter
~
3 .M : 4.g: 1.90
dummrr ._____ 3.79 ' 9.9 2 6 2
Winter _____..__.____
~ ! 2.18: 4 3 1 1.0
Pummrr.. ___ ~. . . . . -. . . . . . . _. . __ -. -. . -. . . :. . . ____ la 3 , 1.6;
Potsdam: i Winter _______ ______________
~
1.99 ! 4 0 ; 0.84
3iimmer _____ 1.35
'I'nuuus Obuervalnry: Winter _______________.__.._.___
~
___.__...._________ 1.40: 4.0: ax, 8.6, 1.34 Summer.. ___ __. . . ___. ---: __ ____ .- __ -. . . ___ ___ __
Winter ____________________---...--.
~
1.84 2 5 1 a59 Bummer ________________________________________----' 1.78: 7.61 a50
2. U4
__. -. . . ___ __ ___ ____ __.
~
__._. _________I L 72 ' 10.3 ,
2. BB i
I k T O S :
I I . - .. -. . - . . . -- .. . - __ .-. - - . - . . .. -
Tlic ralucs obta.inet1. showing the part plrtyed by the dry constituents in the degree of turbidity of the atmos- phere, appear to me to be not improbable. In any case this first attempt to divide the turbidit into the effect
by tlic larger, solid particles (dust, smoke, salt, eto.)
encourages further steps in this direction.
6. Results of t7r.a m.wsurements of red radktion..--The percenta e of the radiation of ~t given spectrum region
radiation passes. We must, therefore, consider the dependence of the nmoimt of red radiatwn on humidity and other factors for given n:ir msses. The lower portion of Figure 2 shows the dependence on vapor pressure measured at the ground. It is noted that with air musses 1, 3? and 5 t-here exists
dmost the same relation, namely, that ,with each milli- meter of vapor pre.ssu.re t7r.u ercsntuge of rcd radiation. decreases 0.2 per cent. W i d greater air masses this value is ap arently somewhat larger, but close1 propor-
eliminate this thus determined influence of water vapor
oil the amount of red radiation then no influence of the dust, smoke, etc.. (trockener Dzmst), is longer recognizable. turbidity *a pears to in. umce the percentage
of thr absorption by water vapor and t T l at of reflection
IS depen c7 ent ohiefly on the air mass through which the
tional to t g e percentage of red radiation. I?we now
?f red "dY" ra zation very lztt r e or not at a e .1. -~
(a) Belt&@ EW Phynik der freien Atmosphh, B a d 10.8.81 8.
MARCH, 1924 MOXTHLY WEATHER REVIEW 159
dski,’ who by chance made radiation measure- ments at t e same time while on a voya e to Siam and L. Java, wrote me that the Equat,or and sout of it he found a lower percent e of red radiation, which he is inclined to view as a pec8iarity of the Tropics. A4ccording t.0 niy measurements it is explained that this is only an effect of the greater amount of water va or in the aw. 7. Results of the measurements ?~,hort-zWue radiutwn..-- As already stated the constants of the incandescent- lamp photometer (with sodium cell) changed, unfortu- nately, many times. It seems, however, that this short- wave light is influenced chiefly b the (Ius!, smoke, etc.
by the water content. Pet I do not renture to give a
numerical statement.
8. Seledve ahsorption by wuter vapor..- -From t.hc results mentioned in section 6 it is nlso possible to de- termine the influence of selective absorption by water vapor, which lies almost entirely in the red and intra-red regions of the spe.ctrum, on the water content. On the basis of the values for each wave length of extra-terre~t~rid radiation and for the transmission coefficients of pure air and of water vu.por determined by C. G. Abbot and F. E. Fowle there may be found for each mass (m) a theo- retical value for the dependence of the percentage of red radiation on the increasing amount of water vapor content, which (value), according to the values of aa derived by E. F. Fowle, doel not include. however, the
If me designate the red coiitend by r, when the water content is w (in cm.) and by ro when the air is dry, then r,,-ro= Ar= am,. Instead of this theoretical vdiic
a, which for m= 1 would have the value 0.0097 we now h d the value a’ = 0.0145, in which a’ includes the sekctive ccbsorptwn. The influence of the selective absorption (dark bands) on the percentage of red radiation is thus
AT= (a’- cy)m0= 0.004S.tur0, in which r0 with this red- glass filter has for m=l the value 56.2, and for m=3
and m=5 the values 62.5 and 66.6, respectively. Un- fortunat,ely this result. for AT is uncertain by about 5 per cent.
9. T?LC daily march oj- the turbidit? factor.-Measure-
almost always an increase in turbidity factor till mi day followed by a decrease till evening: on an average the values for the afternoon ar~~greater than those for the forenoon, whence it follows that over the ocean also there ooours a.n increase during t,he day.
TABLE 3.-Daaly march of the trrrbidity factor (T.)
%
(trockewr Dmst) , contained in t g e stmosphere and less
selective absorption. !#a;
fs
inents of this kind extending over t i e whole day ave
..
4
p. m.
-
3. 73
~)oucneas&rraaes _____________ Argentlna,wuntry __________ Andesat2m)m ___________ B d i d b pl;teaU (3.600m.)..
-___-
(lac. ~it.) were inaccurate since on the one hand they are based on the by no means certain values for extra-tez- restrial radiation and transmission coefficient for pure, d air calculated at the Astro hysical Observatory,
absorption could not be taken into consideration for lack of data. So an explanation of the increase in tur- bidity around midday must be sought.
%shjngton, and since on the ot E er hand the selective
Vapor Pressure (mm.1
I have come to the conclusion that, as the result of the daily vertical convection in the lower air strata, there occurs at the upper limit of this convection stratum an increase in relative humidity and with it an increase in the size of the condensation nuclei whereby the latter
FIQ. I.-De~mndence of the turbidity factor (T) on vapor pressure (e)
Vupor Pressure (mm.1
PIG. Z.-Dependence OF the red content (r) of solar radiatloo on vapor pregsuw (e)
are enla ed be ond the wave length of light and there- after t o t s y redct a portion of the direct solar radiation. becomes recognizable even before the
8 Pearance 09 the Clouds though the Strong Tpdall
saturation (me-condensation stage).
If the aftmoon values were not higher than those for ’ This turbidit the forenoon there would be the obvious assumption that
the values of a, cited by me in the calculation of T. e li ect of such dust-filled air which is near the point of
4 9 3 ~1 la diminution de I’intensitd dans la partie rouge du wonnement solaire, ob- 1 hope to%e able to re ort in eeater detail on this and other results in Band 8, “Benchte des MeteoroZiqkch- .wvw entre 1’Empe et YEquataur” (Comptes Rendus, Paris. 1Q23. p. 764). See also Mn. WEATEER REV., October, 1823, SI: 528.
160 MONTHLY WEATHER REVIEW MARCH, 1924
geophy&d&chen Institutes,” Frankfort on the Main, as soon as funds for publication are available. Ody one result is to be given here. 10. RelaCive dues of sky radiation in the spectncm range of the sodium cell with the sun ut the zenith.-There are available four series of measurements which agree very well, so that the considerations reviousl men-
just at 30’ altitude radiates least strongly. If we desig- tioned do not hold for these relative v s ues. Tge zone
nate the value for this point by 100 then there appears the following distribution:
Altltude _____________ 5* 100 15’ 200 2 5 O 30° 35O 40D 45O 50’’ 65O 600 W 700 7 5 O (100
Sky rrdiatlon .----.... 114 112 1oB 101 101 100 102 1013 109 113 110 1% 144 aa0 319 *500
*Approximate.
Nom.-This expedition was su ported by the Minis- terio de
-
Republica l&mtina the Stinnes Steamship ines, and the Verein der Freunh des Taunus-
Obserz~atOriums, Frankfort on the Main.
THE PHYSICAL-METEOROLOGICAL OBSERVATORY AT DAVOS, SWITZERLAND
By Prof. Dr. C. DORNO, Director of the Observatory
For several years the MONTHLY WEATHER REVIEW has from time to time published contributions from the director of the above-mentioned observatory, and in its bibliography has referred to his works. Recently there has been organized in connection with the observatory a
medical research institute (Institute for Alpine Physi- and Tuberculosis Research), which, in collaborat,ion
the climate in high altitudes on both the healthy and bhe sick. Through this collaboration an institute for research unique not only in Switzerland, but a.lmost in the whole world has been created, which has for its object the combating of that most terrible scourge of
mankind, tuberculosis. In this work it will utilize the rich clinical material which is fre uenting the world-
medical institute is Professor Loewy, the collaborator for many years of Professor Zuntz and he is at the same
time in charge of the phvsiological laboratsory. The pathologic-bacteriological de artment, which will be
soon be completed. From the founding of the observatory in 1907, its investigations have been directed principally to radia- tion studies. These have included the radiation of the
sun, and of the sky, and of both combined, a.s to their total enerwy and as to the energy of restrirt.ed spect>rrd regions; &IO reflected radiation, and noct.urnn.1 radia- tion. Starting from the cliniatic points of view with tLw merely statistical problem of the quantities or intensities of the different, kinds of rays tshat reach the place of
observation, a.nd their variat,ion in intensitv with the hour of the day, the season of the year, and the weather. the observatory soon enlarged its series of problems t,owards geo hysics, and automatically to almost all the problems of atmospheric o tics. The contributions to the climatic questions on t Yl e mThole are given in the nionogra h published in 1911 by Friedr. Vieweg & Son,
hi h mountains,” and containing the constants of ra%iation of Davos together with several years’ records of the atmospheric-electrical elements and radioactive values. The former have been amplified and per- fected in the subsequent ears after the introduction of the hoto-electric metho$ The Meteorologische Zeit- s c d t and the Ph sikalische Zeitschrift have published re orts thereon. $he rogram adapted to the ‘ studies,”
publications, has been followed in the researches of the radiation climate of other places, such as Kolberg, St. Blasien, recently also Arosa, A a (Tessin), and even to
Atmospheric optics has claimed and obtained rightful recognition in the voluminous works ‘‘ Phenomena of twilight and corona around t,he sun” and ‘‘ Himmelshell-
wit “lo%? the observatory, will investigate tho influence of
renowned health resort of Davos. % he director of blie
entirely independent,, is st,il P being enlarged and will
Brunswic P , entitled “Studies on light and air of the
w E ‘ch has also been $ escribed and discussed in otaher
a certain extent in the United !T tates of North America.
i keit, Himmelspolarisation und Somenintensitlit in 8avosy 1911 bis 1918” which appeared in 1917 and 1919 in the Abhandlung des Preussischen Meteorologischen Institutes, Vol. V and Vol. VI. The latter work aims at uniformly comprehending the whole economy of at- mospheric light, that is to say, establishing what has become of the incident solar radiation, and what sort of chapges it has undergone with re ard to intensity,
Eave been devoted to the erfection of recording methods
measurements in the foregoing years. These efforts arrived at an almost coniplete success, as has been shown in “Pro ress in radiation measurements” pub-
ticcording to which Davos is the fist lace in the world t.o cont,inuously record the total exc K ange of lietit by roilitttion during the course of a whole yew. After such ~uc!cessfuI m-ork the Observatory, founded aud maintained by the director’s own means, would have been forced to close in consecuence of the depreciation
of his German propert.ies, hah not, it imty be said, all Switzerlnnd--te Swiss Association for Naturalistic Re- search, Swiss Society for Climat.ology and Balneology, Swiss Red Cross, cant.on and cominunity authorit’ies, Cantonal Medical Association and others-(the sub- vention on the part of the Swiss Confcderation is posi- tivelv promised) undert.aken to aid the observatory, and
H I ~ hfy i t by a medical institute, as already described. ,d a t e d with t.he inst.itute, but entirely free and inde- pendent with reference to its working methods, manage- nient, and name, as well as in its unaltered situation. the observatory exists independently by the side of the inst.it.ute. Professor Dorno has been named au liono- rary member of the institute and nieinber of the board. There is much to be hoped for in the future collabora- tion of meteorolo y, ph sics and physiology, more par-
tains, is to be considered t,he most favorable for such combined investigations. Dorno’s works published in the years 1922 and 1923, “About specific-medical clima- tology,” “On the connection between the extension of the ultra-violet solar spectrum and the formation of
’’ and others, indicate the first directives to be
T r t , o owed by these works of collaboration, by the side of which the old aims of the observatory are being pursued in an unaltered manner. About the foundation, organization, aiid the objects of the Institute of Ph siology it may be briefly said:
are to be medical men or naturalists. To the institute there is attached a scientific body giving advice and offering collaboration, being composed of ‘professors of t.he Swiss universities, not on1 of medical men, but also
olarization, and color. The years P rom 1919 to 1931
on the basis of the metho tl s employed only for individual
Jished in the !if ONTHLT WEATEER REVIEW in 1922,
ticularly as the p f P ace o observation, in the high moun-
‘
The board is compose 2 of nine members, of whom five
representrttives of the meteoro f ogiral and physical faculty