52 MONTHLY WEATHER REVIEW. F ~A R Y , 1917
h e r dust cloud, with its accompanying brilliant twilight colors, might well be observed in the clear atnios here of southern California some days in advance o f the denser lower cloud, and, indeed, before the latter had been observed in States farther east. It also seems fair to assume that this volcanic dust waa at least m part the cause of the high haze observed over the South Atlantic States at the end of July.; and it ma have been a contributmg cause ?f the brilliant twilig E t colors observed on July 30-31 ui the eastern part of the United States.
si/. 5 0 6 : 62-( 96 9 )
FREE-AIB DATA IN TEE H A W A W ISLANDS, TIJLY, 1916.
By Col. WILMOT E. ELLIS, Coast Artillery Corps, U. S. Army.
[Dated: Fort Ruger, H. T., Jan. 23. YS. received Feb. 7,1917.1
The tit.le of t’his article suggests that the usual parn- pheriialia of sounding balloons, captive balloons, or
standard kites with self-reg~stering instruments were utilized in making OUT explorations, but such was licit
the case. Our explorm a paratus consisted. of twi? “home-made” kites an% o f cast-won projectlles fired from lz-inch sea-coast mortars. Alt!iough our esperi-
mental S n g s were conducted .primarily with a view to obtaining ballistical inforni+m, we incident,dy ob- tained considerable infonnatlon of interest t.0 tslie aero- logist. The purpose of this article is to discuss the result8 obtained with specia.1 reference to aerologv. Ex lorations of the upper air within the fiopics have een very limited in number and in the extent of
the territory covered. There has been nonc whatever in our insular ppssessions? Systematic exploration work has been carned on at Batavia in the Dutch Enst Indies. The chief of the 11. ,S. Weather Bureau in a
letter to the commanding officer, Fort, Ruger, under dabe of September 10, 1915, states:
A typical pilot balloon obeervation made by Mr. Van Benlmt?len, in charge of the observatory there [Bataxin], shows the brarle winc!s t,o Iw about 3 km. deep. with a velocitv of 5 m. p. R. The anti-t.rades exten:l from 3 to 17 km., their velocity increaaing gradually from 5 m. 1). s. at
3 km. to 23 m. p. 8. at 14 km. The u per Drade winds extend from 17
to 18 km., and have low velocities lib the surface trades. Between the 18-and 23-km.levels,ahigh westerlywind, velocitylOtol5m.p.s.,
tv88 found. Above this level, to the highest level explored, emterly
winds again prevailed, reaching velocities of 40 m. p. s. in the vicimty of the 30-km. level.
In the Hawaiian Islands, the prevailing winds are the northeast trades snd have a temperature of about 7oOF. The relative humidit averages 65 per cent. These condi- tions are greatly moified by mountains and local convee tion currents. There are two principal ranges on the island of Oahu. The Koolau extends along the nortli- eastern or windward side. The Waianae range is on the .southwestern side. Both ranges are covered with dense vegetation. The elevation averages between 2,000 and 3,000 feet, the highest altitude being about 4,000 feet. Between the two ranges is an elevated tableland. The moisture carried by the trades is largely p p i t a t e d upon these mountams, but they are not hi
deep valleys on the leeward side. The trades are a t least 4,000 feet deep, and-as will be shown later--our
keep the wind from sweeping over them an f throiig enouP the to
~ ~
1 See however 0. L. Fa&: Kite flyingin theTropics. MONTELTWEATHEX REVIEW^
Der. I h , 31:5&567. 5 figs., for an aceoiint of uppr-air observations h means of kites during the expedition to the Bahiunss in 1903,under the aiispiccs of tzc Geogr~phir31 SOClety Of Baltimore.-EDITOR.
mortar firings indicate that they are about the same
depth as the southeast trades at Batavia-approximately
~O ,O O O feet. The trades are generally interru ted by
part of March. The konas are damp and blustering winds, warmer and more humid than the trades. As might be espected, the winds on the leeward side are- during tshe prevalence of the trades-more or less capri- cious. There is considerable diversity in wind directions well above the surface of the earth. True cirrus clouds, whose altitude ran es about 26,000 feet, are not common;
with an anti-trade component. In our systeiii of seacoast mortar firing, we use a series of imaginary zones described about the mortar
“konas” or southerly gales, from November to t % e latter
but, when observec s , they generally indicate a movement
encounters in
001. Rcferty’s e x p r i m n t s , J d y , 1016, at Oahu.
In February, 1915, Col. W. C. Rafferty, Coast Artillery Coi-ps, commander of the coast defenses of Oahu (lo- cated in and near Honolulu) obtained authority from the War Department to fire a series of 74 shots from the 12-inch mortars. The pu ose of the firing was:
in the ninth zone, and the 824-pound projectile m the eigh tnh zone ;
2. To determine the law which governs the devia- tion due to mind; 3. To discover any other information relating to mortar firing which may be useful to the service. The shots were distributed between two batteries, Battery Harlow a t Fort Ruger near Diamond Head Crater, and Battery Hasbrouck a t Fort Kamehameha Pearl Harbor. These batteries are about 11
the former being about 53 miles east of and the latter about the same distance
1. To determine the dri T t of the 700-pound projectile
west thcreof.
FEBRUARY, 1917.
The following was the program:
FIRBT DAY, JULY 8, 1915.
Fire 12 shots from Battery Harlow.
Bhot numbers.
..................................................... .......................................................
1..
a 3. ...................................................... 4 1 ....................................................... 6.. ..................................................... 7.. ..................................................... 8 ....................................................... 9 .................... : .................................. 10. ..................................................... 11.. .................................................... la.. ....................................................
.......................................................
MONTHLY WEATHER REVIEW.
Zone. Azimuth.
55 8 100 8 3 8 0 65 55 8 100 8 280 55
aso 65
8 100' 55 9 aao! 55 9 100 1 55 9 55 55 9 a a o 55
53
Zone. Zone llmits.
Fire 27 shots from Battery Harlow, mid the same number from Battery Hasbrouck in series of nine shots, each series to be in accordance with the following table:
weight
Shot numbers.
Eleva- tion.
315
............................................... x 815
............................................... 5 315
............................................... 9 1 45
I O
81 ;:
...............................................
............................................... ............................................... I 5 I
...............................................
..............................................
Range.
Yards. 5,580 11 920
l O ' l l a 15'000 14:115 12,700
11'256
55 55 55 55 55 55 65 55 55
--
Maxi-
0 t h -
lwhv.
lzzt
--
Yard#. 2 as5 4'251
1'706 5'047 5'928 d774
4*!m
Shots of the same serial number a t each battery were fired as nearly simultaneously as possible.
THIRD DAY, JULY 10, 1915.
Fire 8 shots from Battery Hasbrouck.
Azl- muth.
10 10 10 10 10 10 10 10
Bhot numbers. Zone.
-~
Eleva- tlon.
--
60 50 Bo Bo 50 50 Bo Bo
1.. ..................................................... ' 8
a .............................. :- .......................
1. ...................................................... a 6. ...................................................... 9
...................................................... ..................................................... a. 4.. I !
..................................................... 7.. 8. ...................................................... 1 ; I
Yardr. 4 455-5 976 .......................... daec1S 150 ......................... 8'694-13'150 ......................... 8: agkia: 150.. ....................... 8535~ g;. ........................ ......................... 10: rU4-15:aSl.. .......................
Pounds.
824
700
I
Col. W. E. Ellis, C. A. C., fort commander a t Fort Ru er, was in cha e of the firin a t Battery Harlow,
a t Fort Kamehameha, was in charge of the fking at Bat- te Hasbrouck. The target point for each shot was a point on the sea ~urf&c8 at the range-table ran e corres onding to the ele-
for height of site were made. Correction for tabular drift was applied to each shot. The following aerological stations--some temporary, some permanent-were utilized :
No. 1, at Kupikipikio Point.-This Point is about 13 miles east of Diamond Head Summit. From this station, we noted the direction of the upper wind by kite.
as c f Lieut. Col. Fran % W. Coe, C. % . C., fort commander
vation!-and at the prescribe f B azimut . No corrections
No. 2, a t Diamond Head Summit.-At this station, we took the direction of the upper wind b kite, and the velocity of the [lower] wind as indicated T3 y an anemom- eter located about 40 feet above the
Russy.-This station is on the beach, 30 feet or so above sealevel and about 23 miles northwest of Diamond Head Summit. Here we recorded the direction and velocity of the surface wind, the therniometer, and the barometer. No. 4, the U. S. Weather Bureau Station in Hono- lulu.-Same data as No. 3.
No. 5, our meteorological station a t Fort Kamehame- ha.-This station is about 30 feet above sealevel. Same data as No. 3. The kites used were designed by the Coast Defense commander. They were flown to an altitude of about
800 feet above the surface of the earth. The station at Kupiki ikio Point is 122 feet above M. L. W., and the
The kites, therefore, indicated wind directions about 900 feet and 1,600 feet above sealevel, respectively.
On July 8, the fiing began a t 6:09 a. m. and ended a t 7:55 a. m. The data obtained from the U. S. Weather Bureau station during this period were as follows: Wind E, 4 miles per hour; temperature 74' to 78'F; barometer 30.05 to 30.07 inches. On July 9, the Sing began at 8 a. ni. and ended at 1:48 p. m. U. S. Weather Bureau data: From t3 a. m. to 10 a. m., wind S, increasing from 4 to 9 miles per hour; from 10 a. m. to 1:48 p. m., wind E, varying between 9 to 11 miles es hour; temperature 7s' rismg to 84'
On %ly 10, the firin began a t 8:01 a. m. and, ended a t 8:39 a. m. U. S. Tfeather Bureau data: Wind E, 7 miles per hour; temperature 79' to 80'; barometer 29.96 to 29.95 inches. The essential data for the zones and elevations used are as follows:
ound on a ole. No. 3, U. S. h y meteorologica F station at 2 ort De
one a t b iamond Head Summit, 765 feet above M. L. W.
endin at 81'; g arometer 30.02 to 39.93 inches.
-
6. .... 8. .... 8. .... 8. .... 9. .... 9. .... 9. ....
bs 50 65
Bo 10 65
Bo
Ballisticians in general, and ours in particular, make the following basic assumptions regardmg aerology and wind effects :
(1) Aerological conditions at a given time are re arded as constant over the ran e and may be obtainecf from
(2) Irrespective of wind conditions, a dehite law con- nects the fall of tern erature and barometer with height
(3) A wind-arbitrararily assumed constant over the ran e-may be divided into two corn onents, one par-
thereto; and each component may be separately con- sidered as regards deviating effects. Modern researches in aerology have demonstrated the fallacy of the first two assumptions.
instruments at or near the 5 attery fiing.
above the earth's su 3 ace.
alle Q to the line of fie, and tho ot { er perpendicular
54 MONTHLY WEATHER REVIEW. -my, 1917
Harlow.. ............... Harlow.. Hashrouck .............. Hariow.. ............... Hasbroiick ............. Harlow.. ............... Hsshrouck. .............
...............
. To illustrate the third assumption: Su pose a -
fire. h e assumption IS made that the retarding effect of the wind is the same as that of a direct head wind of 12 miles; and that the lateral effect is the same as that of a 12-mile wind blowing directly across the range. This
assumption, for obvious reasons, has never been tested ex erimentally, but it carries two fallacies and hence is
parallelogram of forces assumes the same Qoint of applica- tion, whch is not the case in the prob em we are con- sidering. In the second lace, the deviating effect of a
for the formulas used are independent. Yet a little con- sideration shows that whatever effect the wind ma have
the deviationslongitudinal andlateral-in this case-must be the same. Or otherwise; the longitudinal and lateral deviations must, when compounded, indicate the result- ant effect of the wind both as to amount and direction. No wind formulas that have ever come to the writer’s notice take this obvious fact into consideration. It is difficult to explain why these untenable hypothe- ses have been made by ballisticians, unless it be that their zeal in applyin mathematical formulas to a prohlenl
has misled them. In any event, one can charge this trio of fallacies with being one of the contributing causes to the inaccuracy of coast artillery fire. The other causes, being beyond the scope of aerology, will not be discussed
in this paper. Conc‘lusions.
jectile were movin into an obh ue hea a wind o p” 16
miles er hour, ma Ei ng an angle o P 45’ with the line of
in R erently incorrect. In the first place, the law of the
12-mile ran e wind and t f at of a 12-mile cross wind are
in general d ifferent as calculated by b&stical methods,
upon the projectile,it must movewith the wind; and 1 ence,
that does not a % mit of an exact mathematical solution
The present writer collected all available data and made A a special study of the Oahu ex erimental firings. brief syno sis, in so far as win a phenomena are con-
cerned, fo 1p ows. After consideration of the Bata.via da.ta, and of t.lie results of the esperinients conducted by the U. 8. Weather Bureau at Avalon, Ca.l., the following tentative hy othesis was formulated:
rl) The winds of t,he trophosphere are arranged in strata. The elements-velocity, direction, and de th-
one stratum are not definitely connected by any ascer- tainable law with the elements of any other stratum.
(2) A variation in the elements of any stratum in- rolves or indicates an undeterminable variat,ion in the
of each stratum are variable, and the elements o f any
8
g i
P j 55 5.5
!ii
.lther strata.
(3) Tho wind effect upon a given r j e c t i l e varies hdeterminatelv with the elevation. ecause. as the
1915.
July 8
July 9
July 9
July Y July 9
July 9
July 9
3evation changes, the number of strata traversed, and
;he time the projectile is subject to the wind effect in my given stratum, vary.
(4) The conce’ tion of a “resultant wind,” or of a
the hy othesis of variable wind strata.
(5) $he resultant fleet of the wind-both as to direc- son and amount-corresponding to a given elevation .may be deduced from firing a t two or more target oints; Dut the data so obtained are of little or no value P or cal- culating the effect at any other elevation; or, for that matter, at the same elevation, after stratum conditions have materially changed. Based upon these hypotheses, certain formulas were
deduced, which it will not be necessary to ela1)ornte. Briefly, t8he problem involves four unknown quantities:
“mean motion o f the atmosphere,” is inconsistent with
I‘ardr. .lM
90 rfi 146
222 160 131
(1) The variation in range due to causes other than wind;
(2) the error or variation in the calculated drift; (3) the n:aximmn resultant eflect of the wind strata passed through; and (4) the direction of the resultant effect. Two target pointe-each iving a plotted ran e deviation
the unknowns, and three target points afford the data for independent checks. Unfortunately, our powder was not uniform and therefore the number of independent checks was quite limited.
and lateral deviation-sord the data for % etermining
Table 1 summarizes the results obtained.
TABLE 1.
I Battery.
1
zone.
i
’leva- tion.
1
Date. I W.1 I
Az.V’.S
I ---- ---__
e
131
- 126
98 ga ea 96
e
101
94 94 112
106 108 iia
so 89
88 91
91
94
94
1 It7 is the resultant effect of the wind In yards,
2 -4z.W.. azimuth of same. or azimuth of that line of 6re which would give the maxi-
8 Ar. Xll-.. azimuth toward which the free surfsee wind was h!owing, ns indicated mum incnasc of the rmg due to wind.
by the kite flown from the summit of Uianiolld Head.
Firings in the ninth zone, July S, did not furnish suffi-
Table 1 warrants the following conclusions :
(1) During the firings, the free surface wind was about east.
(2) The resultant effect of the wind corresponded quite closely in direction with the free surface wind, althou h
the projectiles, southwesterly win& were encounterei This is shown by an increase of azimuth of W over 1i.W. and a value of 1.1’ less in the ninth zone than in the eighth zone. uite uniform. The t,wo batteries were, as sta.ted, 11 m8es apart; yet the values of h .W . show n remarkable agreement. The values of 113 except for the eighth zone, also agree quite closely. The following su Iplementary table shows t.he results
of t,he t.liircl day’s k n g tit. Hsshrouak. They were not incorporated in Table I , hecttusc exact data for calcula- tion werc! insufficient,. Hence. the results are only ap- Imminiat,e; but! they have not been rejected, because t.hny are so anomalous as to merit iiivest.igatioii, even on t i n
approximat.o basis.
TABLE 2.
cient data to cnlculatc 1Y mid Ll2.W.
there are indicnt.iozis that in the up er strata reached %
(3) Free wiuds along and offshore are
8 H8SbrOUCk .............. Do .................. Do .................. ..... Do .................. ..... 190
.....
A2.W. Ar. P. 11:
“lie indications are that. on the mornin- of July 10, the surface Trades were quitc sliauow ami tfist, as t ~l r pro- jectile ttscendcd, it cucomitcred frst southeasterly wviiida:
and then, Inter, strong northwestarlv winds. Otlicr c.nnc:lusioiw-iiot, deducible from the Rbovo
lnl>les-- ;ire :
Tiie winds close to the sui-face of tho earth showed con- siderable variation at different points along and on shore,
M. W. R., February, 1917. ‘TO face P. 55.1
4
Fig. 1.-View of part of ht-floor exhibit. Im@ary wall decoration at back. Fig. 2 .4 o m e r of Weather Bureauexhibit showin glass map and the regUhr Station instrumeits (at lek).
I
T
t
Fig. 3.-General view of Weather Bureau’s aerological exhibit. Fie. &-View of ~s r t of first-floor exhibit,
m. 6.-Detail views of Bosch balloon m e t m r o q h (left) and mocMed Marvin kite Fig. &-Detail view of the Blair recording balloon meodolit8, exhibttcd by the Weather Bureau. meteorogsph (right), exhibited by e Weather Bureau. ,
F E B R U ~, 1917. MONTHLY WEATHER REVIEW. . 55
and:such winds did not, ‘as a rule, correspond at all with the .‘‘kite winds.” Wind data taken on shore and near the earth-say within 100 feet or so-are utterly a t v,mi&nce with those obtained in t.lie “free air” above tlie surface of the sea. Hence, empirical formulas hnseci upon surface data are worthless. The velocity of the wind as indicnteci 011 t.hc summit of Diamond Head was from two t.o three times its great as
that indicated at the Unit.ec1 St.nt,es Wc?nt.her Bureau station hi Honolulu. Ballisticians have arhiarwily assunmd t,hat the drift of
the project,ile is independent of wind codit,ims, whereas
a little a priori reasoning would have shown t.he fallacy of this assumption. But, be this tis it may, our firings proved conclusively t,hat t,he drift, did vary with chnligis in wind conditioiis. All who have followod t.liiu discussioii. will midouhtod1~- :~gree that the const artilleryman nttcniphg t,o hit il
moving target at sea has a pret,ty prcdi1c.m to d v e ,
considering t4hat his accuracy of fire depends upoil u~ihowi aerological condit.ions, uiik~iomii vwin tions hi drift, and unknown changes in the muzzle ve1ocit.y of t.he powder employed.
5s/.5 ( 73-
mATHEB BUBEAU EXHIBIT AT TEE FIBST PAN AMERICAN
AEBONAUTIC EXPOSITION.
By WILLIS RAY GREW, Meteorologist.
[Aemlogical Inveetiptiona, Westher Bureeu, Mar. 14,1817.]
The First Pan American Aeronautic Ex osit.ion was
ruary 8 to 15, 1917. The purpose of this ex osit.ion was
exhibits and to proinote the more rapid trdvancrment of
this science by nieans of addresses and clisc.ussiona. The latter were given each day in the Convention H d and were illustrated by lantern slides and motion ictures.
Bureau’s motion- icture illustration of met~eorological kite flying at the &exel Aerologicnl Station The exhibits occupied the two lower floors of the palace. Those on the first floor consisted, for the niost
the Wright rothers made a successful Ai ht. at Kitty Hawk, N. C., in 1903. In the open court a ove tlie first
floor were suspended a large military kite balloon and a model of a manned free balloon. These and some other details of the first-floor exhibit are shown in figures 1
and 4. On the second, or mezzanine, floor were shown niodels of aero lanes and dirigibles, various types of motors and
exhibits, consistin principa ly of aniphlets for distri-
Security League, and the National Advisory Committee for Aeronautics. A part of this floor WM devoted to exhibits b some of t,lie Government, de artnients,
Survey, Army and Navy, Postal Service, and the Weather Bureau. The Weather Bureau exhibit consist.ed of most of bhe instmental equipment usually shown at expositions wid, in addition some of the instruments, apparatus, etc., used by the Aeroiogical Division. The usud exhihit hiis already been described in previous numbers of the MONTHLY WEATHER REVIEW. (Vol.43.~. 4$2. and vol. 44. n. 459.)
held in the Grand Central Palace, New l’or K - City, Feb-
to stimulate general interest in aeronautics K y nieaiis of
Of considerable interest among these waa t.he t Veather
gature bein the first motor-driven machine, in whic E
art, of different types of aeroplanes, an interestin
% %
T
some o P the later designs of rope1lei.s. There were also
bution, by the h an American &on, the National
including t J: e Bureau of Standards, Coast ant f Geodetic
son memometer so modified that e1ec.tric contact.is.ritade for each one4xtieth of a mile of wind blown,.thus enabling the observer to determine the current hourly velocity by merely counting the number of.contacts made in one minute (see this REVIEW, 44 : 288). An electric’ fan operated this anemometer; also one connected in the usual way with the triple register. The latter a d a barograph and thennograph were kept continuously recording. Much interest ww shown in these instru- ments and in the glass weather map, which showed the weather conditions and the forecast for each day. The general arran ement and appearance of this part of
large number of descriptive pam hlets on “The Weather
tributed during the oxposition. The aerological exhibit included a kite, k t e reel, record- ing t,heodolite, 2 kite meteoro raphs, 1 balloon meteoro- rubber, a number of free air records obtained by means of kites, captive and sounding balloons, and co ies of the Mount Weather Bulletin and Monthly Weat er Review containing sum- maries of free air work. Figure 3 shows the kite, with meteorograph attached, kite reel and some of the in- st-ruments; in figures 5 and 6 the instruments can be seen in somewhat greater detail. All of this apparatus has been in regular use by the Weather Bureau, except the recording theodolite which is of ‘recent design and construction. Its use in pilot or sounding balloon work will require but one observer, whereas, with the non- recording theodolite, it has been necessary to have two observers; one to keep the balloon on the cross haifs, the other to record the angular readings. Much interest was shown in these instruments and in the piece of sounding bdoon rubber, it bein pointed out that all of our.pure
that no satisfactory samples have yet been produced in this country. Greatest interest was apparent in the meteoiwgra h
and in the summaries of free-air data. It was evident that comparatively few of those actively engaged in avi- ation are aware of the existence of tables and ‘charta showing temperature and wind conditions at various levels and under different conditions of pressure distri- bution a t the earth’s surface. The direct bearin and
result that there were numerous re uests for the sum-
this line that may be issued in the future.
the Weather B ureau exhibit are shown in figure 2. A
Bureau” and “Ex lanation of t f e Weather Map”; also cards explaining t !i!l e flags used for warnings were dis-
raph, piece of sounding baloon f
rubber balloons have % een obtained from Europe and
records, which were briefly described on attached ca 1.8 s,
value of this work to aviators was emphasized, wit 5 the
muries already published and for a1 4. publications along
s5/. s?6 (q/?
SOUND AREAS OF THE EXPLOSION AT EAST LONDON,
JANUABY lQ, lQl7.’
By CIURLES DAVISON.
It is not, often that a great explosion occm near the cent,er of a PO ulous area, and the recent disaster in East hiidon, England, thus offers an opportunity of adding t.o our knowledge on the transmission of sound waves by t,he atmosphere. * * * The most remark- able result [of recent investigations in this subject] is the recognition of the fact that there exists sometimes, not always, a zone of silence which separates two detached sound a.reas. This zone has been traced in 20 recent aplosions (excluding that of Friday, January 19), two
Besides these instruments therk was’also shown anRobin: 1Condcn.d from Nature. London, Feb. 1,1817, a: 48&4iW, by W. Q. Reed.