MAP,.2931 MONTHLY WEATHER REVIEW 187
I
THE RADIATION CONFERENCE AT BERLIN AND POTSDAM,' FEBRUARY 23-26, 1931
By H. H. KIMBALL
[Westher Bureau, Washington, D. C ., April 30, 13311
Minutes of the first three sessions have been abstracted
by H. H. Kirnball from a manuscript furnished by A.
Angstrom, R. Siiring, and K. Biittner. Minutes of the
last two sessions have been translated by W. W. R e d .
The first session of the conference was held in the
meteorological observatory a t Potsdam, on February 23.
The following were present: A. Angstrom, Sweden; W. Morikofer, Switzerland; F. Albrecht, K. Buttner, P Dubois, G. Falckenberg, K. Fuessner, H. von Ficker, FV.
Huhl, F. Linke, VI'. Marten, and R. Suring, Crermciiy. At later sessions, T. Burgeron, K. Hahler, A. Defant, H.
Hergesell, C. Muller, F. Schmidt-Ott, and K. Stuchtey were also present.
Dr. Angstrom opened the session with remarks relative to the objects of the conference, and stated the reasons for
giving atmospheric turbidity such a prominent place on the pro ram. He then presented Dr. Suring as presiding
Professor Linke found hiiiiself in accord with hgstrom
in questioning Fowle's determinations of the scattering of solar radiation by aqueous vapor in the atmosphere. He
held that the vital point of the discussion is whether the
amount of turbidity shall appear as n factor (I= Ioe-RT"L) or as an additive term (I=Ioe-""-~"). He also pointed out that the turbidity must be capable of ecisy and accurate determination, and be independent of the air mass.
Angstrom considered it advantageous not to include atmospheric absorption in the measurement of turbidity.
Also, in agreement with Buttner, the dependence of tur- bidity upon wave length is recognized Therefore, he
recommends that the definition of turbidity be in such form that the reduction to a known wave length is easily
accomplished. The turbidity coefficient, j3, fulfills the*e
conditions, and under mean conditions is independent of
the wave length. The dependence of the total tux-bitlitg
estinction on the wave length is espressed by the exponent
P a in the term -. xa At the second session of the commission Linke, Dubois, and Fuessner again discus ed the dependence of turbidity
on the wave length, and hgstrom emphasized the fact that by the use of suitable measurements and computa-
tions the turbidity factor, the total turbidity extinction,
and also the amount of precipitable water above the sta- tion can be determined. A discussion on the use of
Schott glass filters in actinometric measurements fol-
lowed. The third session met at 10:30 a. in. of February 24
in the room of the "Notgemeinshaft der Deutschen Wis- senshaft" in Berlin. Professor Siiring proposed that the
morning session be given up to a discussion of the yues-
tion "What apparatus or what method should one rec-
officer f uring the session.
1 To readers not familiar with rerent literature on atmosphric turbidity. n briefstate- menf of views held by difierent in\wtigators niay be helIiful in interpreting the ,:is-
cussion at the conferenre. Linke would include in atmospheric turbidity, T all atmospheric depletion of solnr radiation ercept that due to molecular sratterinp, n h h lntter IS e A s .1 ~ com~~uted frbln
Raylelgh's equetions.
kn(rstr8m represents atmospheric depletion by d 0 i r o a J n , in whirh a, is the IW
eflirient of scattering due to causes other than gas molecules, and including lhat which 6 E'omle found associated with ammspheric water vnpor. lie expressas at in the formi,
in wbirh 6 IS the atmospheric turhillity. The term docs not include depletlon throligli absorption by atmoslheric gases, 1,rlnripally by water vapor. Under average condirionP
Angstrijm Ends a== 1.3, which, in contrast with A' in the erprsssion for molecular scatlw ing, indicatw that the d iameters of the scat teringparlicles are appreciably lager than the diameters of gas molecules.
He represents Rtmospheric depletion by r e i T-.
oniniend for t,he polar year? " Emphasis was laid on the
importance of nieasurements of the in tensity of solar
radiation wit,h hhe sun at, different heights, using radia-
t'ion filters controlled by t'he Potasdam observatory, so
13s t,o insure uniformity of results at different stabions.
Angstrom pointed out t>he iriiport>ance of reducing the
angular opening of the pyrhelioimter to about So, or at
least all observers should give accurltt,e information on
t,he size. of t,he ope,ning of their pyrheliometer. Upsda, Washington, and Potsdam were designated as pointas a t
w1iic.h pyrhelionie,t,e,rs might be st'andardized in known
pyrhelioiiiet,ric units. I n the. afternoon a new absolut,e pprhe,liomete.r was
inspected at t,he Physikalisch-Technisclien Reicha,nstalt,
a t Charlo ttenburg . Fourt,h session, Wednesay, February 25, 10:15 a. ni.
at t,he iiie teorological obse.rva tory, Po tsdain. The following subjects were discussed:
1. Discussion of the term air mass. By air mass there
can be designat,ed eit,her the true air mass
in - -. sec. z, or sec,. e. *- 760
In this sec. z is to he taken as the synibol for t,he Bem-
porad funct,ion. Both measures have their advantages.
A decision (between the t,wo definitions) was not reached.
2. Aft,er a review of all the u de,terminations, the value
u = 8.26. lo-" was designated as t,he most probable, since
botQ t,he most, re,c.ent measureiiient,s as well as the theo-
rebical ctLlculrxt'ions give t,liis value.
3. Report, of Doct,or Bergeron, of Oslo, on the eye observations of t,he opale.scent t,urbiclitfy in t,he service
of synoptics. The, following proposals we.re formulated for. presenta-
t,ion t,n the int,ernat8ionn.l me.t,eorologicrtl organization;
1. The measurements of direct'. solar radiation are to
be organized in such manner t,liat i n addition to blie total
deple.tion of t,he atmosphere. there can be calculated from them t,he t,urhidit,y free from selec tfive absorption by
water vapor. To this end it is recomniended that all
st8at,ions employ glass filters of the same coniposit,ion and t,liickness. The meteorological observatory, Potsdam, is ,willing t,o procure and gage such filters. Special instruc-
tions on the nabure and use of the fi1te.w will be prepared.
2. Since the investigations relative to a decision on a
st,anclard scde for pyrheliometric measurements are as
yet unc.omplete,d, it is reconmiended for the present to
refer all nieasureiiie,nts to the Srnithsonian scale of 1913.
Readings from in~t~runien ts standardized in terms of the
Angstrom scale can be reduced to bhe Smithsonian scale by bhe addit'ion of 3.5 per cent.
It is recommended that t,he standard pyrheliometers
to be used during t,he pohr year be compared before and
a.fter the expedition at Upsala, Pot,scla.m, or Washington. In order to eliminate at a later date the falsifying
influences of skylight in the mea.surements of direct solar rndiat,ion it is necessary to give, in additmi t,o the type of
instrument used, as exactly as possible the aperature condihions of the actinometer (length of tube, size of outer
orifice, size of inner orifice, or size of t'he object-glass
surface).
3. It is recommended that a t favorably located polar
st,a.tions, where there is available ti sufficiently scientific
personnel, there be carried out measurements of total
b
5M M!mT$fl,Ya WEATHER' IXBXI'EW MA*, 1932
instruments used are to be adjusted to standard appa-
ratus. Suggestions for carrying out such measurement's
will be specially prepared.
clewnass af, air, @or of sky, qaomalous refraction (meas-
ihlhtioh ahd ~d/d&k~&' o u h h d - radihtim. The . "~=8;%3 r.lO!?J:~bM/i-Tt 1
(5.76. 10-12-watt/cm2. T4).
In conclusion Herr M orikofer reported his experiences in the g+ging of cadmium cells and the advantages pre-
(as a filter), Later, 3 .~ Kubl presented ~~urvea ~k ~m
measurements bee' up by Qn Thursday, February 26, fgom 5:30 b .7 p. m..&iere
discussion of theIrnatho& of messwements cadmium cdl; those taking part were Mesars. BOttqaY,
Dubois, Feussner, Kubl, Morikiofer, and Siirmg.
4* Abtsstipq is cdled to the Of Of
wemen@, of, the dip of the horizon), t d i g h t , earthlight
sented by t&ing into c~~sldemtian f i l a t h d of IrYes%ke-
Mld diOhm't the emP'oYmdnti Of Mihos dassd
(Nachtwhein), and zOdhca1 khb. Details On the his ne^ a h e d potaHium cell.
Professor Maurer (Zurich) and Dr. F. Schniid (Oberhel-
(Signed) A. ANQ~EOW. , I
R. SUI~ING.
I I
I(. ~BUTTNER. I I)
nstant there is
I
~Y !N G WEATHER IN THE CORPUS CHRISTI AREA I
I .
By J. P: MCAULIFPB.,
[Weather Bureau Office, Corpus Chrlstl, 'lbx.1
Month
JBduarp ____ - ___. ... ___. - ....
~
Pe@upy.--,. .__.___________ March ______ __ ._...__ - ._..___
April - -. - - ___. - - - - ___ ._ ._ - -
The "Corpus Chsisti mea'' as usually referred to by amiators in this section e x t d roughly from Beeville, 56
miles north, to Kingsville, 40 nliles suuth, and George
West, 70 miles west. In this small area there is consider-
able diversity of weather, usually eff ectiing visibility and
ceilj ng . There are three elements most vitally eflecting flyinn in
this. area namely: Fog, wind velocity, and thun8er- storms.' h e s e three'hnndicaps to flying should be care- fully studied by aviators in this men.
Records at the Corpus Christi Weather Bureau show
that during the 44-year period, 1887-1930, inclusive, the average number of dense fogs 'has been as follows during
the months indicated :
Numher of ddnw iogs Month Number of dense fogs
3 October __..__ . __._______.._
2 Navember ________.._...___._
2 December .._.._._......._._
1
Durin
A peculiar condition exists at Beeville.
the other months of the year fog occiirs so
Fogs are much mope frequent there, and within 5 to 10 miles each side,
thdn the &re at' Corpus' Christi. Mnhy mornings when Corpus &risti and Srtn Antonio report peilfect visibility
Of
Christi at hand they fly high and soon come out into clear weather. Occasionally aviators have left Corpus Christ,i withotkt &st getting weather data, and in many of these
cases they were forced to turn back when new Bee~ille,
not attempting to fly farther, because they assumed that
the fog continued northward.
The cause of lthese re uent fogs in tihe vicinity of Bee- ville seems to be due to %e slope of tihe land eastward t o
tihe Gulf, the presence of San Antonio and Copano B q s
that'indent the coast line sharply in the latitude of Bee- ville, and ppobably dso the kransas River that flows past
Bseville. These lowlmds and water meas here cause air cwrents from the Gulf to flow westward, meeting the cold
interior air, and causing fogs. In thickness and their local1 chamcter these fogs reeemble the mists and fogs of
the, 'eastern mountain regions. The frequency of these fogs leaves no doubt (that a sharp temperature gradient
exists in that locality, especially in the winter months.
seldom t % at it is practically negligible.
course and ceilink wit weather reports from San Antonio and Corpus &viators rim into dense fog at Beeville.
These fogs are not confined to any parti
weather, but occur with b h pregmre, ps w
barometer is low. They cf issipate usuyll about 10 a. m.,,
but occasionally persist yntil noon or t& miaafterpoop.
The average thickness of these fogs is 1,00d,feet., I I ,
The second great handicap to safe byiqg i s tb velocity on this coast. The writer's attention was first directed to the erratic
wiud velocities in this section by a letter from one of the' officials of the T. A. T. Corporation. h ' h i s letter the official mentioned $he fa at reports from San Antopio
were requently mislea beqause the weathqr ,was
subjeqt to such erratic chazlg mentioned strong head urn&
elements. This would be, of coqrse, s
or south wind for the pluneg that 'were c
Antonio. The prevalence of these w h d justment of schedules by the T. A. T. I t was noticed
tlihc the planes would enter these winfly regions sudded from a regiQn that had given qnly modqrpte soqtheq P y breezes, and this windy condition almost' invariably
occurred within 10 miles of Kingsville. (The planes
Sometimes it reaches 30 niiles per hour. This annoyance can be avoided. somewhat, by aviators either going far inlmd and avoiding Kingsville, or swing-
ing Gulfward north of Corpus Christi. The wind velocities are not PO great on the Gulf beaches as they are on the shores of the bays. The sea breeze also cames
another peculiar atmospheric irregularity, thunderstorm
that are difikult to forecast. From direct observation at Corpus Christi it has been found that thunderstorms occur two or three times more
frequently at Robstown, 14 miles westward, than they