JULY, 1914. MONTHLY WE.ATHl3R REVIEW. 466
drawn according to the Cla eyron method. Of these two
graphic computations, while the latter offers special ad- vanta es for theoretical investigations. On the other hand, 5 0th methods have one defect which is, indeed, of
only ver minor fundamental importance, but which may yet be Lurid annoying by those who have had little ex- perience in considerations of this kind. This defect arises from the fact that in both of these methods the changes of condition ex erienced by an
and those of a descendin mass of air by rising curves.
by chan the coordinates, aa has already been done by Prof.%%.ham M. Davis for the Hertzian diagrams. I will, however, here assume that the more generalized Clapeyron method is employed in its usual form; that is to say, the volume is represented by the abscissae and the pressure by the ordinates. If we represent a cycle by this method, then, as is well known, the areas of the surfaces inclosed by the dia am are a measure of the
theorem, as used b me, the simple diagram is replaced by
in conhtion, and hereafter I shall refer to ths projection briefly as the diagram. The question whether in this process work is clone or consumed,can be answered a t once from the direction alon which the curve is traversed. If the change in con d itiou proceeds in such a way that the ditigrnm inclosing the surface is traveised in a clockwise direction, then heat is consumed and by this process work is gtiined; in the opposite case, work is consumed and heat is gained. Therefore in any atmospheric cycle, e. g., in the eschange of air between cyclone and anticyclone, i t suffices to enter in the diagram the actudy observed values of the res-
the values of pressure and temperature) in order to at once recognize whether in this process we have to do with a consumption or a gain of heat. If, for instance, we assume that the atmospheric ascent took place in a summer cyclone in which the tem erature
sentative diagram will be traversed in a counter-clockwise direction. In this case, therefore, there is a consumption of work and a gain of heat. But such a process can not possibly contain within itself the germ [or cause] of its existence since the earth receives energy from without
only in the form of heat, which is delivered by the sun at a higher temperature and subsequently radiated from the earth a t a lower temperature. The great atmospheiic cycle as conditioned by the general circulation must, therefore, be traversed in nn opposite direction to that just described. It must, in fact, be one in which heat is converted into work. Processes such as that above imagined, although they do seem to corres ond. to the interchange between
lem never to be e s lained by the convection theory, but
circulation delivers an excess of mec amcal ener in order to develop or sustam smaller processes oythe op ositekind. From this it is clear that even pure thermodynamic considerations may lead to results that are of the greatest importance for the understanding. of. dynamic processes. Consequently, we recognize that it !s a problem of the highest importance to test numerically by means of
methods of presentation, t R e former is better adapted for
ascending mass of air are represented % y falling curves
This, however, is a diilicu f ty that can easily be overcome
work done or consumed. Y n the extension of this
the projection of t z e spacecurve representing the change
sure and volume (or what amounts to the same t R ing,
is lower than in the attendant anticyclone, then t R e repre-
cyclone and anticyc P one in summer time, are neverthe-
are only conceivab f e in case the great c cle. of the general
rl
well-established observations the considerations here set forth. The construction of such diagrams by use of actually obsemecl data would lead to the most far- reaching conclusions. Of course, i t will not be easy to obtain the values for truly closed cycles, since probably only a part of the air that is raised in the cyclone and transported over to the neighboiin anticyclone returns again into the same cyclone. &ill the cla.ssification of temperatures observed a t different heights, ac.cordin to the cyclonal or anti- cyclonnl character of the weat B er, will be a contribution in this direction.
t,he moisture is varinble. If, in a current of asceiidiiig or descending air, the quan- tity of moisture in a unit, mass remains unchanged, then we are judfied in supposing that no mixture mth other niasses of air has taken plnce. The change in t.he quantity of nioisture, therefore, gives in n certain sense a measure of the degree of mixture with foreign masses of air, but alwcJ s only under the assuniptioii that it has not left the B rystuge. uestions whose thorou h explanation
show that from the diiigraiiis of atmospheric cycles con- st,iucted from data actually observed, the most important conclusions can be drawn as to t,he general circulation of the atmosphere. In the construction of these diagrams, however, we need above a.11 a knowledge of the tempera- ture nnd t.he moisture at different altitudes in the regions of mcending and descending currents and a t different times of t,he day and the tions should not be con middle ltitihdes; circulntion between the high pressure
But these are would lead us too P ar. At present it is on F y necessary to
I . .,
"
. ,.
ICE STORMS OF NEW ENGLAND.
A welcoiiie study of the ice stornis (verglas; Glatteis) t,ha.t have been observed over New England and notably a t Blue Hill Obsei-vntory, Nasq., has just come from the pen of Charles F. Brooks..'
1 Brooks Charlea P The ice storms of New England Cambri e 1914 8 p 2pl 4.. (Har&d Univdsity publication.) [Reprinted fmmAnnals,%L. H&. dau., r: m p t . 1.1
456 MONTHLY WEATHER REVIEW. Jar, 1914
The author finds the following combinations of condi- tions which may produce ice storms when there is precipi- tation:
~
I. Tempemture of the air below OOC.
ture of the air above OOC. and 11* X?r emperature of the rain below OOC.
1. From passing through a &.Faturn of cold air; 2. From cooling by evaporation in nomaturated air.
1. &xawe of m i d d cold; 2. fiom cooling by evaporation in nomaturated air.
B. Tempemture of the rain above OOC. and Tern erature of the obects coated, below OOC.
He finds that no heavy ice storm occurs when the teni- perature of the surface air is above O O C ., nnd that no coii- siderable ice storm has occurred nt Blue Hill, Moss., under such conditions- but the above coiisideratioiis show i t to be not impossibie. When the temperature of objects and the temperature of the lower air also is above O O C ., it is clear that even undercooled rain and such ice pellets tis
may reach the ground will not be able to form a n ice coat-
ing. When the air is below OOC., undercooled rain or ice pellets will not adhere in the frozen state to obects at
into icicles. If the lower air is warmer nnd the under- cooled rain, etc., does succeed in forming an ice coating on previously cooled objects, still the surrounding air will cause the ice coating to melt without forming icicles. Ice a t o m may occur with a temperature as low as - 13OC. ; i t may rain hard or gently; the wind may be from an direcbon, a ga!e or a calm; the temperature may rise, fall or remain stationary. The author then presents a diagram showing graphi- cally the vertical and horizontal distribution of tempera- ture conditions as they affected the precipitation that accompanied the storm of Januar 5-6,1910, a t Blue Hill.
six fl ours a t the valley station (18 meteis above sea level) and a little over one hour a t the summit (195
meters above Ma level), while a neighboring station standing above 400 meters would have esperienced no ice storm at all. Thus local topography has a great effect on the jntensity and extent of an ice storm. into the distributions of pressure and win that cause t ese ice-storm temperature inversions it a pears that there are three general wind conditions w L ch roduce.thern: (1) $ann aw arriving over residual cold air (the
 southerly type).
(2) Cold air coming in below while warm air is arriving above (the northeasterly type). (3) Cold air from the north or west pushing in below a
rain cloud (the northwesterly~ type). The ideal conditions for the first type occur when, after the a h next the ground has been strongly cooled by radia- tion during an antic clone, a cyclone arlvnnces rapidly toward New En l a d The conditions c h i n Jnnunry
tration. Apronounced antic clone (1,043 mbars) had
southwest bringing a large sup ly of w p i i , inoist air on
Mexico. e are presented
active cyclone m the south at the same time thnt an anticyclone in the north is supplying cold air. The north-
a &her temperature; but the dripping water wil 1 freeze
It a pears from that study that t g e ice storm lasted about
U on inq
5-6, 1910, &ea f y referred to, furnish an escc fl ent illus-
been replaced within 34 hours TI y a cyclone froin the west-
south winds in front of a troug 1 extendmg to the Gulf of
when there is a good supply of warm sout 9R ern alp from an The ideal conditions for the second t
STheaathor umd the Harvard College notation of absolute unlts erhaps In con- lormit with the ldm put lorwurd by Prob. A. E. Kennelly in thlSs8mmw, March lOl4,d: 141, aeotlon 8. The editor here adheres to the prevaiUnp international us& mnmg nmtwrologbh, vls, the bar of BJarkneu.
east wind blowing toward the southern cyclone is pushing cold air in under the warm air flowing northward from the eastern portion of the cyclone to the south. Often, how- ever, the undercurrent from the northeast is not cold enough to wholl counteract the warming effect of the
stntionary or even rise slowly instead of falling. An ice storni of this northemterly  type occurred February 19-22, 1898, n1so on December 23, 1908, and February 9,
1905. In this last case a kite flight at Blue Hill showed the lower wind ESE. with gradually falling temperature
(- 1 to -2 C.), the valley temperature being a few de- grees h her. U to almost 800 meters the V. T. G. was
wns an inversion to +0 .5 O from a minimum of -3 C. at
760 meters. At that level was the base of an arriving warn southeast wind ; snow had been falling for the pre- ceding hour and n half. A similar ice storm occurred over all of northern Germany on October 19-21, 1898 (see full account in Das Wetter, Berlin, November, 1898, p. 247-
260); but in that case both the northeasterly and the northwesterly types were in progress simultaneously at cliff erent levels. The northwesterly type is about the reverse of the first or southerly type. The cold air wedges in below while rain is still falling above. The changes in the om of the precipitation occur in the opposite order also. The wind-shift line, or boundary between two currents hav- ing different directions and temperatures is of coiumon occurrence but its assage is not frequentiy accompanied by an ice storm. iebruary 15, 1906, resented a repre-
though the beginnin of the storm belonged to t
two or even three of the. types described, we may best classify them rtccorclins to the positions and movements of the highs and lows producing them. Two large divi- sions may be made on this basis: A. Storms in which anticyclones in the. north dominate cyclones on the south; B. Stornis occurring from cyclones and anticyclones in the usual regular sequence. All the 31 ice storms occurring under conditions A were either of type 2 or a conibination of types 2 and 3 ; 11 of these were severe storms. Most of the ice storms studied occur under conditions B, the severe ones being most common when the low comes from the Gulf of Meluco. The following tabulation shows the frequencies of the different types:
Btormr.
1. Southerlyt pe ............................................. 67 2. Northeaster& type ........................................... 116 3. Northwesterly type .......................................... 59
The northcasterly type is favored by southern lows nncl northern highs; the southerly t e by the low
south wind over z ead, then the temperature may remain
nearly P t le norni s a.diabatic one; but at 855 meters there
sentative stonn of this type over the P Tnited States, al-
Owing to the fact t Y iat a single ice storm often f aP 1s under e 2.
crowding in close behind the h h; and ?I t e northwes- terly t e comes most frequent 4T y when the high arrives close be P mid the low. The distribution of ice stornis by months was ns follows:
January ...................................................... 48
February ..................................................... 46
March ......................................................... 40
April ......................................................... 7 November .................................................... 10
December ..................................................... 27
Average year. .......................................... 12
The earliest fall storm came on November &lo, 1894,
and the latest spring storm was on April 30, 1909.
Among extraordinary features mcom anying meren t
8 O C,, lasting many hours during the storm of January storms at Blue Hill may be mentione a an inversion of
JULY, 1914. MONTHLY WEATHER REVIEW. 467
28-23, 1904. During this storm the alternating gusts that affected only the top of the Hill caused simultaneous temperature fluctuations of 5' in either directioii, l a d w but as man seconds, as though the sumniit of the HiB
warm current and the lower cold current. The week 12-17, 1909, brought three severe ice storm2 to
two of these storms and showed a most interesting rapid destruction of the inversion by the advent of the anti- cyclone, there being an inversion of 6' between 950 in. and 1,050 rn. at 11 a. m., by noon the inversion had dimini5hed in skength but doubled its areal estent, and at 4 p. m. it had diaa During this time the sum- mit temperature at $E?-?:i had remained stationary. Mr. Brooks concludes as follows:
Re 'ons of strong cyclonic action bringing precipitation and highly
variafie temperatures seem to be most subject to ice storms. Thus eastern North America,and western Europe are particularly suece tible. Toward the continental interiors when cyclones are weaker tfere is a di- fre uency of ice storms. In this coun!T, aa in Europe, cyclones frequtm8 aupport an ice storm for a cona erable distance acroaa puntry. d r instance, the ice storm of February 21-22, 1913, began 111 Texas and eventually crossed New England. The storm of January 6,1910 waa reported aa causing much damage in New Jersey the morning of h m r y 5. To forecast these storms for New England is even more uncertain than to forecast rain or anow, for the belt of occurrence is generally narrow. Ice storma may be much more local than snow storms. Predictione muat be based on the occurrence of cyclonic and anti- cyclonic paxitiom favorable for ice storms, and in making forecasts indications of an ice storm already in progrem in the best would help. *-[c. A., jr.]
were precise s y a t the waving boundary between the upper
The kite flight of the 15th occurred between
AN APPRECIATION.
by the United States to illustrate an
The map on the back [of the Daily Westher Map of the United States] (in equidistant En lish projection) mm made especially to delight the rneteorolaxt w%o aqhw alway 40 see thinge from above, secretly hopb that may thw more rapidly eolve the problem preeented by J e elementa in whoee midst w e live. At a lance one ma now the mtuatzon over the whole Northern Hem*%erewre& c c onee and irnticyclonea which play, 88 we bow, 80 important a 1-62 in the forces of nature, and we see at the
BBme tiqe the .distribution of temperatures. What u partwularly mterestmg to the profeesional is the day-to-day comparison of these charta; we certainly make no mistake in predictr ing that this innovation will be roductive of dkoveries, and that detailed study of these charta w i i ut UB on the right trackl if not of the real and complex cauaea of &e origins of them &ahone, Ft least of the yatems to which their movementa belong-which wlll add great weight to the vdue of the forecasta. At first glance the notations of the map are a little disconcerting. The fact is that here the C. G. 5. system of absolute units has been
1 Vmdwyver. Les nouvelles rartfa synoptiques du'( Weathm Bureau"de Washing- ton. Ciel et term, B~uelle9,1914, Juin, (16: 160-172.
602!Zi!-lU
$0 ted for the barometric pressures, and the reading am expressed
wa &rs; the bar corresponding to a force of 10 dynes (1,OOO rmllibsre being equal to 29.53 inches, or '750.06 mm. of the normal mercury column), and the temperature i a given in terma of the absolute zero,
It goes without saying that, from a strictly scientific standpoint, one can but ap rove of the adoption of these units; but in cornideration of the fact g a t , on the one hand, the very oung science of meteorology must be made to appeal to all ita well-wiskbrs (and for this ver reason must reach out beyond the limited circle of the profession) an8 on the other hand, in view of the wide distribution planned for this chart, it is not a priori clear what advantage is to be gained b thus breakq away from the deeply rooted customs of the general puhic. Ercept for this gentle criticim, which is. moreover, but an ex reg-
aion of a eraonal opinion and detracts nothing from the work ofthe Weather Sureau, we are certain that our readers will unreservedly admire the excellent chart that we present. I have collected,2 for teaching urpoaes, samples of a large nymber of meteorological charta publieheah Europe, and we must admit that the American publication far surpasses the similar ones that have been secured from other countries. Undoubtedly the reader will mk for the cause of this inferiorit There are various reasons; I believe one of the most important is di acattering of our efforta. The practical Americans have concentrated the whole meteorological service of their vast territory at one aingle point and have thus been able to give the resulti total the scope that we see before us. In Europe, on the other han? each country is confined to ita own boundaries. he they broad or narrow, and gives only what these permit. The totd interest, energy. and initiative Europe thiis expends, probably equals i f it does not exceed that dedicated by OUT
traits-Atlantic neighbors: but our efforta lack coordination and, to use
a business phrase, our enormous general expenses tie up a large portion of our ~a p i t a l .~ Because of its geographical location [on the weatern ahores of the continent] all of western Europe is in a rather difficult poaition from the meteorological point of view. * * * In Rhort everything seems to argue in favor of the creation of a cen- tral meteorological service for Europe, well planned and well oqan- ized such aa ia that which existe or America. But alae, our anclent Europe, with ita get more ancient ideas, haa difficulty in escaping from the grip of c auviniam. We allow ourselves to be stifled under the enormous expenses incurred by our military affairs * * * and we can not find on our old earth one voice canying wei ht enou h to atop theae follies. we throw our lllillions into the gulfof an afmoat criminal insanity without bein able to bring about that calm of which we have such need, and to w%ich we all aspire. America, taking a
broader view, has thus far rele ated to the background that which we have placed first, and &e ran d u e further the greater good of humanity by giving more liberally to acience and to progress. Let ua thank her for this beautiful example that ahe seta us, and vow that some day Europe, wiser, shall do aa well.
-273' C.
NOR-RN HEXIBPHERE XAP INTERRUPTED.
The following announcement ap ears on the Weather
Owi to the atate of mar involving the great nationa of Euro e, the meteoxogical observations from regions in Europe and Asia gereto- fore em loyed bv the Weather Bureau in the construction of ita chart of the iorthern -Hemis >here are no longer received, and the imie of this map will be EU enied from this date until such time as the reports can be resumed. The publication of the daily map of the United States will be continued as heretofore, and those recipients of the ma of the Northern Hemisphere who make application therefor, inclutf ing paid subscriptions, will be listed to receive the weather map of the United Staten. Unless application is received the map will not be sent, except to paid subscnptiona.
Map of the Northern Hemisphere P or August 6, 1914:
C. F. MARVIN, Chief of Bureau.
* Such a wlleetion may be seen di hyed in frames in the library of the Washh&$m
I Italics are OUIS.-EDITUB. office of the U. 8. Weather Bu&.-X. A., jr.]