NOVEIUBER, 1925 MONTHLY WEATHER REVIEW 475
partly on account of convection and partly perhaps on account of direct absorption. A consequence of these conditions is that a number of the meteorological elements observed at the ice show periodic and unperiodic changes which are of a ver local character because they take place within the col J layer
directly above the ice. This circumstance seems to be of fundamental importance for the understanding of many of the meteorological conditions over the Polar Sea, and will be taken into account in the fuller discussion of the meteorological observations of the espedition.
METEOSOLOQICAL CONDITIONS IN THE EURASIAN SECTOR OF THE ARCTIC
[n summary of the data and mncluslons prassnted by Karl Schnelder, A. Berson. L. Breltluss, M. Robitrsch. R. Biiring. A . Wegmcr, and K. Wegener, In "The airship BS a means of explorntIon In the Arctic." I]
By BURTON M. VARNEY
[Weather Bureau, Washington, D. C., Novembrr, 19251
It is perhaps not widely known in this country that an organization called the International Society for the Study of Arctic Exploration by Means of Airsiips is actively en aged in working toward a solution of this problem. ft IS composed of some 80 European scientists, including leading meteorolo ists, oceanogra hers, geog-
Nansen is its president. There were, a t the time t e memoir here summarized was published (October. 1924).
For the border region of the Arctic in the Eurasian sector, cloudiness data are presented in Table 2 (Franz Josef Land and Spitzbergen), and in the large table a t the end of this paper appear diLta for the five months MarchJuly a t 19 stations corering various periods
(mostJlp less than 5 years) from 1 to 33 pais. The
i
raphers, geologists, and PO P ar explorers. 6r. Fridt'of distribution of these stations is shown in Figure 1.
., one American member and no%nglish. The problem of air navigation in the Arctic is essen- tially a meteorological one. es of the
nent available meteorological data, with special reference to the Asiatic sector. Cloudiness and fo and wind
ma'or attention. bi'ovdiaess and fog.-For the area north of SOo the only cloud data are from the traverse of the Fram in 1893-1896 from near the mouth of the Lena River to Tromsii in northern Scandinavia. The mean values are set out in Table 1. They indicate clearly a summer maximum of cloudiness, and the fact t.hat the period of the long night had somewhat less than half of the summer amount of
cloudiness . Fog, while showing a summer m&ximum, was never- theless nearly absent throughout the autumn, winter, and
Hence some 18 p 60-page memoir are devoted to sumplarizing Tl t e perti-
directions, togetrher with the controls over t 'd: em, receive
spring.
TABLE 1
Jan. Feb. Mar. Apr.
Cloudiness I io)
Days with fog 3.7 4.4 5.6 5.71 7.21 8 .5 \-R 8 l 8 .8 8.2 6.4 4.4 3.7 6.2
0 0 2
1 1 2 1 101 201 I6 101 5 1 1 0 67
The intensity of development of clouds, fog, and precipitation
* * * is, for the polar re ions proper, very limited. According to the Fram observations &e monthly amounts of precipitation
FIG. I.-Stations represented by data in Table 8.
TABLE 2
were about 3 mm., although in one exceptional case in July there was a fall of 20 mm. in a day. * * * There is no month without snowfall. b i n falls mostly from May to September only, in any case in those a r m which lie far from the oDen sea. The snow cover
Jan.
-
I l l I I
grows during the course of the winter to a-very heavy mass through
the condensation of atmospheric moisture on its surface, the tem- perature of which is mostly below that of the air. This form of precipitation it is not possible to measure. Rime and hoarfrost, on the other hand, while found on a few days, in general are observed only in limited quantity and in regions near the sea. Hoarfrost as we observe it in EuroDe. is to be classed among the rarities in the
Franh Josef Land
aal 8.1 I 8.0 I 5.2 I 5.3 I 5.8 I 7.4 i
I a 3 I I I
'03
I 7'8 .I I 7.g
Spitrbergen
Arctic, because the witer content of the atmosGhere, on account of the low temperature, is BO much smaller. The danger of an ice SO far as Ch.ldiness is concernec& Franz JoSef Land
deposit on a traveling airship is therefore less likely than in Europe. and Spitzbergen are dreariest in summer, with little to An airship journey in the Arctic summer seems, therefore, as far as choose between them. In midwinter, however, while
the meteorological factors are concerned, not seriously more diffi- at F~~~~ Josef Land has declined to *bout 5 , cult than a similar trip in the European winter. at Spitzbergen nearer the o en sea, it has decreased only
1 Publlshed by the Internationden Studiengesellscbait rur Erfonehung der Arktls
altitude of the clouds. At Dickson Harbor, in longitude mit dem LuftschiE, Oct. 7 1924. (Co y received by the U. 8. Weather Bureau Library tmm the ~ase~lschait fiir Brmnde, L n .)
to 6. These data are for c s oudiness without respect to
476 MONTHLY WEATHER REVIEW NOVEMBER. 1925
Height (km.) ______ 1 \ 2 3 4
----- I NE ______________________ l i I 10 19 13 11 8 SE ....................... SW ...................... E 31 38 NW ...................... 24 j 38 39 , 41
about 80' E. at the mouth of the Yenesei River, pilot-bal- loon ascents weremadein 1917betweenJanuary 12 and Au- gust 31. They throw light on the fre uency of cloudiness above certainahitudes at that point in t x esector,as follows:
TABLE 3
5
19
13 27 42
I / Jan.-Apr.
~~
41
16 24 25
50 1s
No ascents on account of bad weather-- --. . . -.. _____ - _______ thelow 0.5 tm _____._.... _____._._._
Measurements of balloon between 0.5 and 2. __._____________
I lover 2 km _____._.. .. . .._._________
The most striking facts shown by Table 3 are (1) t,hat during the period JnnuaiT-April iliglits were either omitted or reached but a half kilometer of measurable altitude only one-quart,er of t,he t.inie, and t,hat they made better t1i.m 3 kilometers of measurable altitude half the time; and (3) t1ia.t the May-Bugust period was quite the worst on t.he scoreof bnclweatlierandlowcloucls, ody l8per cent of t,he flig1it.s bein mensurable beyond 3 kilomet.ers.
we have some evidence from Alesanc rovsk (longitude about 34' E.) in tlie lar e t.able st the end of this paper, showing that the periof Mnrcli-April, 1909, was one of bad weather with much cloudiness mid rain, though with- out winds of storm velocity and without. fogs. This short period may or may not have been representative.
It is at least suggestive. Prevailing ur.tnds.4inc.e these will be the areatest factor in determining an air route from westernkurope across the polar basin to the west coast of North America and the east coast, of Asia, a knowledge not only of tlie general features of the ressure distribut,ion and t.he
changes of wind and weather are of prime importance.
On the coasts of northern Asia the winds are strikingly regular. This rim of the polar basin may be briefly described as an area of dominating monsoon winds. This appears with great clear- ness st almost all the north coast stations, at which in the winter months the southerly wincls prevail, indicating the outflow of air from the central Asiatic hyperbar, while as early as the spring months a profound change in the distribution of the winds takes place in such a inanner that now ~iorthcrly and northeasterly winds predominate. Clearly, the wind conditions of the Asiatic side give thc impression of a marked monsoonal development.
Evidence of the existence of these monsoons a t the sur- face in the Arctic fringe isgircn on the basis of four stations in theEura.sian sector and one in ~heNortli Americanscctor.
9
For the general con( 7 it,ions in tlie re ion farther west,
resulting winds but also o e thmcyclonic and antmicyclonic
TABLE 4.--FVind frcqurirries in pereentagcs
Ix.(NE./ E. JsE.1 s. Ifiw.Jw.bw./cms
-
___ .______
I Franz-Josef's Land
* TABLE C.-Wind frequencies in percentages-Continued
Winter __ __ - - _. Summer ____ __ -.
Winter _.______
Summer _______
.. .
March ________ .4 ril__________
June. ___. _____
d a y - __. - - ~. . -
I
--
Ustjansk (E s t Siberia)
I
Pitlekaj (Chukchl Peninsula)
Point Barrow (Alaska) Average wind form
I
18
9
16 12
The verticil estent of the monsoons is important, but the only esisting data on this point are not sufficient to form a basis for conclusions. They are the summary
of pilot-balloon observations above Diclison Harbor, shown in Table 5. The ninnsoon is, of course, not evident, since the data cover both sunimer and winter nion ths.
TABLE 5.-Percentnge distribution of high-altitude winds above Dickson Harbor (nftfr P . Ilfoltechnnofl
Numberofcmes---I 103 74 I 54 1 37 1 26
Cyclonic winds .in the Arctic.-According to the Fram observations, tlie nrerage ma..rimir.m wind velocity in the polar basin proper was scarce.1-j over 10 m./sec..; only rery seldom were velocities over 15-15 m./sec. observed. In brief, the basin appears to be practically storm free. Cyclones ap ear to be phenomena of the rim of the
but infrequently. What are the wind velocities in this border region 1
For the sector which includes Spitzbergen, Franz Josef's Land, and Nova Zembla one may usually count on the region being overlaid with a low-pressure circula- tion. We have data (in the large table at the end of t,his paper) for Alexandrovsk and Mdy Karmakuly showing for the earth's surfaco mean wind forces (Beau- fort) rangin from 3.2 to 7.5, with calms a t the latter station (on %ova Zembla, 33 years) ranging from 13 to 17 per cent of the time. With respect to the winds aloft, data are presented in Table G for maximum wind veloci- ties u to 5,000 meters over Spitzbergen in the sunimer half &prilSepteniber) of the years 1912-1913. They show that the lowest niasinium velocities occurred not at ground level but at some elevation less than 1,000 nieters (13 ni./s. a t 500 m.)
bnsin rather t R an of its interior, penetrating the basin
NOVEMBER, 1921 MONTHLY WEATHER REVIEW 477
TABLE 6.--Maximum wind velocities over Spitzbergen, sicmmer half, years 1918-15
Altitude ________ I ,“I 500 I 1,;
1
1,;
1
2,;
I
3,:
1
4,;
1
&a00
-.___
-- -- -- Velocity (m./s.) _______ I 121 24
This point is of interest in connection with the question of the robable thickness of the polnr cap of surface cold
of the rim does not appear to be excessively windy. This is in spite of the fact that, so far as thev hare been mapped: the traveling c clones in this region have notice- ably steep gradients. ft is pointed out that allowancc must be made for the great poleward increase in the deflective force of the emth’s rotation and the conse- quent decrease of the gradient wind, as shown by Table 7.
TABLE O.-Gradient wind velocity in relation to pressure gradient and latitude. (Wind in ?n/a.)
air, to \ e referred to later. In general, then, this sector
Pressuregradlent _____________ I 0.5 1 1.0 1 1.5 I 2.0 1 2.5 1 3.0
--__----
36.7 55.0 18.6 27.9
127 19.0 9.9 14.9 8.3 125 7.3 10.9 6.8 10.8 6.5 9.8 6.4 9.6
________-----______.____ 37.2 46.5 ________ 25.4 31.7 3S.L
19.8 ?4.8 29.1 16.6 2C.8 24.0
14.6 18.2 21.9 13.6 17.0 20.4 13.0 16.6 19.5 12.8 16.0 19.2
That is to say, in the Arctic strong pressure gradients produce only moderate winds. In the climatological observations of the Cerman Spitzbergen Observatory [is found] an illustration of this in the fact that a pressure change is not always correlated with a .@eat increaae in wind velocity. In October, 1912, the nionthly minimum pressure (737.7 mm.) was observed about 60 hours ahead of the monthly maximum (772.3 mm.). The surface wind in connection with this change amounted to S Beaufort (det.er-
mined by the value 1P16 m/sj, while the velocity at 4,000 meters altitude only rarely exceeded 20 m/s.
There is a distinct seasonal difference in the behavior of the cyc.1onic centers after they leave Europe on their eastward journey. In the colder season those remnants of cyclones which manage to get beyond Europe move mostly north of the Asiatic coast, from the region of BarentJs Sea, proceeding thence slowly eastward to Bering’s Strait, on account of the dominance of the Asiatic hi h pressure. They intensify the coastal south- west win& which are the winter monsoon flowing from this high pressure. The summer cyclones move mostly over the northern part of the continent (hence not over the polar basin proper) and serve to intensify the easierlg and northerly winds which are the summer monsoon flowing. from the relatively high pressure in the polar area toward the relatively low pressure over dsia. At all seasohs, from this polar storehouse of cold air, come the quasi-periodic southward thrusts of that air which, operatin in conjunction with warm air streams
cyclones or to produce new ones. Weather ch.;rts for the polar rcgion.-It is not practicable to reproduce here the five series of synoptic weather maps presented in the pa er under consideration. These
international polar year 1552-83, and are of partlcular interest because it ap ears that of the many manuscript
from more sout E ern latitudes, serve to energize existing
charts are based on t R e observations made during the
charts drawn on the K asis of these observations only a
very few have ever been published? The five series are based on the North Atlantic charts referred to in the
footnote, plus data from 21 high-latitude stations, includ- ing 6 polar stations all but one of which are north of 70’. The polar cold cap.-Evidence is presented by the authors to show that in all probability the cap extends to no great height above sea level:
Disregarding the thermal influence, atmospheric pressure must decrease * * from the Horse Latitudes toward the pole. The cold due to radiation, however, causes a collecting of cold air in the lowest atmospheric strata within the polar region proper. The equatorward boundaries of these cold air masses at the earth’s surface Bjerlrnes has called the polar front. * * * This polar front does not estend symetrically about the pole. In the transi- tion months the center of gravity of the cold air cap lies somewhere between the North Pole and the North American Archipelago, corresponding to the larger land masses there present. We have here on a large scale the same features as those shown on s small scale by the weather situations over every Arctic Archipelago, such, for example, as those shown for Spitzbergen by Hurt Wegener. According to that view the island produces a local high-pressure area which overrules the effects of the general pressure distribution, and clearly reveals itself by causing its own chsracteristie weather conditions. The wind blows from the interior through the fjords to the sea. The general movement of the air along the coasts is anticyclonic; and corresponding to this, the surface movement of the ocean also is anticyclonic, which consequently maintains the west coasts ice free, in contrast to the other coasts. Some aerolog- ical data will serve to make this clear, which we take from the dis- cussion of G. Renipp and A. Wagner, “Temperature conditions over Spitzhcrgen ” (publications of the German observatory in Spitzbergen). They present the temperature distribution on the occasion of several ascents. On the ascent of the 8th of March, 1912, which took place within the zone of influence of a low pressure area, a cold stratum ex-
tended to some 200 meters above the earth’s surface; during a
transition weather type on the 15th of April it extended to only about 100 meters. Even on the ascent of March 23, 1923, when surface temperatures were much higher, the cold surface stratum estended to some 300 meters. * * * Aerolog-
ical records will probably confirm the fact of the slight vertical estent of the cold-air masses. As a corollary to this, it is likely also that the low-pressure areas of the far north extend to but a
moderate height, and t h a t their progression depends only upon the temperature conditions on their two flanks. In these regions
the effectiveness of the general west-wind drift is inferior to that of the kinetic energy derived from the juxtaposition of air masses having different temperatures. That is, we must conclude that the velocity of progression of cyclones in the Arctic is less thanin lower latitudes. In harmony with this forward motion. the cold air in coastal cyclones over northern .4sis must originate in the polar basin proper, while the warm air from the southwest-. energized by the strong cyclonic activity in the region of Greenland, Franz Josef’s Land, and northern Scandinavia, streams thence eastward along the coasts. The storehouse of cold for these low-pressure areas iS
* * * not the “Asiatic center of action.”
Diaausion..-It is of interest to compare the altitudes of the to of the cold stratum on various occasions,
at which occurs the miiiimum of win velocity over
S itzhergen (Ttlble 6). The figures point to the inference t K a t this zone of minimum wind may corregpond to that of transition from the polar cold cap (believed by the
-4 similar condition holds for the polar “anticyclone.’J
Experience confirms this conclusion.
given in t B. e above quotation, with thelrobable height
2 Charts for the 1st snd 2d of February I S 3 after A. H. Hazen, are to be found in the Eann-diirlng thirdedition of the LehrbuAh de; Meteorologiw for March 8and9as asup-
plelnent to the Observation of the Lady Franklin Bay Exdeditlon and for April 30 to Mav 3.1683. in Eqlouzrd Vincent’s On the mnrch of barometric deb-sslons of the Arc- tk -polar reEion from the month of September 1882 to the month of August 1883. Academie Royale de Belglque Classe des Sciences Memoires, Deuxiame Serie, 111. R V Z I ~S P I ~. isin. Vincent avidektlv drew dvilv ch& for the whole of the international
&i-$iir-bit puhikiiid i n i i t h i s i i o t d . -The-most complete published charting of the reauldofthis year’s observation3 are the “Synchronous weather charts of the North Atlantic and the adjacent contlneqts for every day from,AuguSt 1. .lF l o August 31, 1883 published under the authority of the Meteorologlcal Council. London, 1885. Thdsechartseitcnd onlv to 70’ north latitude. hut are esuocially valuable onaccount of -- thssh~observatios from the North Atlantic;
478 MONTHLY WEATHER REVIEW Nom-, 1925
E.
7 1
6
authors to be very thin) to the overlying body of warmer air. Detailed knowledge of the conditions and changes in altitude of the zone are of considerable importance. If the assumption be correct that the polar ca averages
logical results cited leave little opportunity for doubt on that score), the question arises as to whetrher the southward displacement of such very thin slabs of cold sir could function adequately in the energizin of cyclones in the manner described by the authors. there seems to be a difficulty in harmonizing this view with that
but a very few hundreds of meters thick (an a the aero-
recently the effect that when they appear to
S.
--
5 5 0 39 15 10
boundary surface between this cold layer and the rels- tively warm layer above. That similar conditions exist north of northeast Asia also is shown by Doctor Sverdrup in the preceding paper in this issue of the MONTHLY WEATHER REVIEW. He points out that there is little ossibility of an intewhange of air between the lower col It would appear, then, that the PO ar cold-surface stratum exercises a quite secondary function in the mechanism of polar cyc.lones and anticyclones. It may be regarded as a lubricant between the rou h earth's surface (ice
cyclones. Doubtless when an outbreak of polar air pushes the polar front into lower latitudes, the thin surface layer partici ates in the movement to some extent. But one fin& it difficult to believe that its cold front is the cold front. The observed depth of polar air streams on the occasion of outbreaks of polar .air in middle latitudes seems entirely against such a view.-
layer and the u per "warm" one.
P $
surface) and the air streams in t E ese cyclones and anti-
B. M. V. \
Msch.. A ril ___ day_-. June ____ July-----
TABLE S.-Extract from observations on the north coast of Russia (L. L. Breitfuss)
-----
-8.6 +1.8 -a8 -6.0 +2.5 -19.8 +0.6 +a8 -10.2 +4.9 +3.4 -0.6 +12 2 +26.9 +2 7
6 tationa
3.2 4.2
4.1
3.3 4.5
Waigatz 1911-1917-- -
6 0
a 1)
2 i ti
41 3
28 a
Jugor Sohar. 1914-1917-
I \l ~C h -- A p r I L - May-..- June ____ July _____
Mora Sale, 1914-1917-.-.
-19.3 -4.5 -34.5 -12. 4 +l. 7 -32 1 -9.5 +3.0 -%4 -0.5 +3.2 -6.4 +1.7 +4.9 -2.4
Obdorsk, 1891-1808----.
5.0 5.7 4.9 5.0 4.8
Steamship Dymphna 18838 (in souther; ham Sea).
9 9 18 16 5
Steamshlo St. Anna. March-
~
p i ]----
June ____ July _____
March-. April----
JUIE---.
BY ....
May ____
Muly-..
1913 (betwecn pGc 77O-7Q0 N. and long. 7l0-77O E.).
-22.6 I -6.2 -39.0 -a6 I +6.2 -s o
C3.0 i+20.0 +1.2
+3.4 .+IS. 7 -1.2
-2i. 2 ' -4.9 -41.0 -ZO. o 1 +a I -38.4
+as : +s.2 -24
-3.0 +RS -13.7
-4.6 ! +2. 3 -13.1
4-6.2 I+lQ.O -1.7
Dickson. 1916-17-.. ____.
Doudlnlca, 1912-1914.--.
I Tcmperature
Mean Max. Min.
Month
I I I
March. - -15.1 I +O. 9 .i p r i ~-- -io. 3 I +L 7 May---. -4.4 i+13.2 June-.-- 4-1.1 l+16.1
July ____. 4-6.4 I+??. 1
March.. -20.0 I -1.0 .4pri1____ -9. o I +3. o Yay -... -3.0 I +L O June--.- +3.0 I+lO.O
July----. +7.0 I+W 0
March. - -21.0 I 0.0 April--.- -9.0 +3.0 May--.. -2 0 +6.0
June--.. +5.0 +PRO
I
'
JUIY---.. +io. o +3. o
-36.1 -31.5
-7.4
-9. 6
-37.0 -31.0 -15.0 -10.0 -3.0
-4 2 0 -36.0 -1% 0 -6.0 -4.0
-42 0 -33.0 -17.0
-2 0
-1.0
I
Wind I Days with-
21 13 14 9 8
14 20
3 11
0
..
7
33
IS 13 11 8 17
4
5
14 19 21
21
22
4 4 5
7 15
4 13 11 3 5
11 15 3 14 22
1 19 28 17 37
.--.
Frequency (in per cent)
__
E.
-
1 13 8 9
8
18 12 10
16
10
m
._-_
13
; I
7 5
7
12
5 5 7
7 9
8 3 9
6 18
17
8 8 7
7 33 19 P 24
14 20 6
9 6
._-_
?a
a
19 15 12 16
.__.
5
2.3 27 15 12 4
14
8
7
4 5
5
5
10 4 2 5 5
15
10 12
13 8
10 1 14 8 4
13 I 6
16
3
.__.
8
12
13 I1 7 7
13
5
24
31 17 18 15
8
2
14 13 9
7 10
I7 16 3 2 5
5
13 7 4 2
3 0 13 2 5
13 6 10 8
3
nv.
10 2 3 4 2
9 9 Y
1)
8
21
-
12
5 5 1: 14 6
28
9
13 12
11 9 11
5 15 3 6
7
4 13
19
22 33
33 13 23
9 13
11 10
15 8 a
_.
W.
-
1 11 11 4 4
4
7 8
10
10
5 2 14 6 2
21
12
9 12 16
15 10
6 8 7 13 4
7 11 13
11
18 9
11
16 11
1 Q g
11 B
:
._-_
.__-
?a
-
w.
0 4
22 15
3 4 11 18
12
19
10
4
4
8
. 13 20
l?
20
5 7
9 14 10
3 7 13 9 2
17 8 16 18 15
1 3 8 11 4
I2 10 9 12 la
-
i n
._-_.
____.
Cloud-
,redp- Clear Cloudy iness :ation weath- weath-
I
er
I
er
I --1-1-14
7.0 4.6 10.2) 6.1 5.7 4.3 11.6 6.3 7.8 7.5 ;: ;;:: 7.5 7.4
9.8 2.3 14.1 7.1
1 5.5 5.6 7.5 7.4 a 3
____--- _____-. _____-. ___---.
6.7 6.4 9.8 9.7 9.3
5.1 6.5 7.3 8.6
8.7
1 Wind velocities in mls.
I Precipitation refers tb the year 1908.
* Observations of wind velocity, days with cloud and days with precipitation are from the steamship Vnma, whlch at thI8 same time was drifthg in the harp Sea.
reclp ation
(19 im.)
NOVEMBER, 1925 MONTHLY WEATHER REVIEW 479
TABLE 8.-Eztract from observations on fhe north coast of Russia (L. L. Breitfuss)-Continued
Stations
Steamship Eclipse. 1915 (Taimyr Coast near Cape Wlld 75O 40' N.. 91' 25' I&).
Stenmshlp Sarja. 1901 (Talmyr coast, 76' 8 N., 95's' E.).
Bulun, 1914 ____________
Karatchb, 1801-1905-.-
Steamshi Sarja 1901 (Nxpnich H'srbor, Siberia Island, 75= 22' N.. 137O 10' E.).
Rousskoe Oustle, 1895 1903.
Nizhne Kolymsk, 1901- 19a.
Pitlekai, 1879
1 Temperature
I
March.- -29.7 I -4.8 -45.1 April ____ -13.3 +1 Y 35.4 May.--- -7.0 I +,7 115.0 June ____ +1.4 ,+10.2 -3.9
h$arch-- -228 -10.4 -40. Y April ____ -23.1 -7.2 -39.1
June ____ +0.4 '+10.4 -8.2 July--.- +2 S lf12.8 -1.7
July _____ +2.S 1+15.1 -3.0
Mny-.-. -S. S I +2 4 -20.6
March.. -34.3 I-18.6 -47.5 April ____ -21.6 I -4.3 -37.4
June-.-. +a0 4-125 -126
March-- -30.1 -124 -426 April ____ -17.9 I +3.0 -41.4
June-.-- +lO.O 1+264 --4:6
July _____ +15.6 I+28.9 +2.9
May -... -Y.B I +3.3 -27.3
July _____ +4.9 +El -0.2
May .... -4.6 +7 5 23 3
March. - -32.7 '-24.6 -40.1 .4pril____ -21.Y 1-11.8 -36. 2
Mav-.-- -11.0 -0.9 -220
Junk ____ +0.7 I +4.4 -9.S July _____ I +2. 1 j +i. 8 -1.7
March. - -31.0 '-14.1 -48.0 April ____ -21. 11 -3.0 -44.8
May ____ -6.4 +6.2 -2Y.9 June ____ +4.8 +29.6 -11.7 July _____ +10.8 ,-t?S.5 -1.3
March.-I-27.1 1-0.8 -48.6
April ____ -15.4 ' +?. 2 -38. U
May ____ -2.0 ]+IS. 4 -31.3 June..-- +lo. 1 +25.0 -a8
March-. -21. G -4.2 -39. B April ____ -18.9 -4.6 -38.0 May ____ 1-6.8 +1.S -20.8
JuIJ- _____ t l 2 .l -tZ8.7 +0.4
June..--! -0.6 +6.8 -14.3 July _____ +2 7 +11.5 -1.0
I 1 .-
relocm
Wind I Days with- I I
2 4 5.6 5.5 2 7 2.8
4.8 5.2 7.0 7.1 6.4
4.7
6.8 8.9
6.1 3.6 5.3 5.7 5.4
2.7 3.5 3.9 4. 8
5.2
5.4 6.8 4.3 6.8 5.8
3.8 3.0 4. 1 5.2 5. 2
2 4 3.2 3.2 3.4 3. 1
-. . - - - - - - - - - - - - - - - - - - - - - - . - - - - - - - - - - - - -
-
N.
-
1 4 9 10 15
2 3 1 7 5
1 2 5 4 16
35 17 40 13 23
1 7 9 9
13
2 11 14 8
12
4 4 6 11 10
6 9 16 15 20
20 37 24 29 10
- -
-
rlE.
9 13 7 19 29
3 5 6
10 4
5 7 9 11 21
3 6 25 27 33
0 11 9 7 12
0 16 14 20 5
8 11 8 10 8
6 9 9
9 Y
6
6 18 7 16
-
- -
Frequency (in per cent)
-
E.
6
7 12 15 2
16 9 16 7 13
22 23 23 27 37
0 1 4 7 10
S 14
25 18
I8
20 2s 11
18
25 31 27
23
12 12 IC
1C
1c
-
m
40
1: I le
- -
-
$E.
9
2 7 4 2
13 3 10 10 11
25 14 16 19 18
1 0 1 2 2
21 5 15 11 9
55 16 8 8
16
6 10
17 14 13
20 27
21 25 19
6 2
3 2
7
-
- -
-
6.
-
5 16 10 4 4
9 2 17 20 7
14 7 9
7 0
10 9
1
14 8
13 5 6 4 6
16 3 11 5 11
2 3 3 5 Y
6
6 7 Y
7
13 5 8 14 15
- -
__
IW.
23 41 21 6 8
26 13 17 18 19
7 11 9
R
0
14 18 1
-
1;
12 8 4 3 5
1 2 3 2 5
26
17 6 5 5
11 6 0
7 9
8 8 5 ?o
18
- -
-
w. -
6 9 10 6 13
7 18 16 22 27
12 21 15 15 0
5 6 3 8 4
15 17 13
10
11
1 1 4 1
10
11 11 8 11 11
1 8 E
e 9
1
6
E 3 1
- -
-
IW.
-
1 2 12 4 8
1 17 3 4 9
3 10
11 10 8
1 6 5 3 4
6 14 15 18 23
0 3 12 21 23
4 6 7 10 12
5 8 8
12 12
24 28 19 16
8
- -
Cloud- Itation
:alm
THE EFFECTS OF A LIGHTNING STROKE
N. ERNEST DORSEY
[National Research Counclll
On the night of Sunday, Se tember 13 a tuli tree
ning. It was examined the next morning. %n the following day it was ins ected very carefully and photo- gra hs were taken. &her photographs were taken anfinspections were made €rom time to time, for the purpose of confirminu or of extending the memoranda previously made. TKe case is of considerable interest, as the efiects produced give uite clear evidence of the
to very restricted areas a t points not over about 8 feet
(Liriodendron tulipi era.) in t % e yard of All gajnt's Chapel, Annapolis f unction, Md., was struck b light-
direction of the stroke, and s 'b. ow that it was delivered
from the ground. Some rain had fallen earlier in the evening; it is not known Dositivelv whether it rained much after the
-
stroke, hut the "appearance, ound in the corner by the ste Rct that leaves and dirt were
but little after t 8' e stroke. of the tower (fi
The prominent objects in the nei hborhood of the tree are shown in Figures 1 and 2. %xcepting a one- story concrete building about 60 feet to the east, there is no other tree or other prominent object to the west,
6) indicate
north, or east within 200 yards of those shown in Figure
1. On the south there are trees, but the nearest is 75 feet distant. The group shown in Figure 1 is essentially isolated. The round is near1 level to the south, west,
east. The tree which was struck is A; it was 47 feet high, and 6 inches from the ground it had a girth of 49 inches. It stands between a 56-foot tower (wood, stone founda- tion, no lightnin rod) and three other trees of approxi- mately its own teight; of these, two are of the same kind as itself. The highest and most exposed tree in the ard is B; it was not damaged in the least. The
plane between C and D, each about 47 feet tall, and finally struck A about 8 feet from the ground. The most distant s linters were found a t K and L; they were small. &all splinters were on the roof of the chapel, one was sticking in the frame of the door. The on1 lar e section torn from the tree lay a t E; it was
Sg. 7). At%, was a splinter 11 feet lon inches in section. With the exce tion o a 4 foot sp inter
and north, an 8 slopes gradua 5 y downward toward the
stro z e ignored both B and the tower, passed in a vertical
14 S B eet one, and was bent about as indicated (see also
P a:d0-5 iy lm5
which was caught in the branc !l es, and which will be