a6 MONTHLY WEATHER REVIEW JANUARY, 1925
involved in establishing shore connection. The activity
of the Jacques-Cartier in this respect has been constantly During the return voyage of March-April
1924 (Vancouver to Bordeaux) she received 61 observa- tions from French ships and 338 from foreign ships of
all nationalities. Certain of these vessels kindly acted
as relay stations for the picking up of observations of ships still more distant. On the Atlantic the observa-
tions received averaged some 30 pe? day.
This network of oceanic observations, of an extent and
closeness hitherto unknown, reaches Paris simultaneously
with the regular observation of the Ja.cques-Ca.rtier, and
France insures their being brotldcast throughout Europe
by incorporating them in the meteorological message sent from the Eiffel Tower.
Very recently (November, 1924) a still greater advance
has been achieved by the use of .very short wave lengths (115 meters). The meteorological. niessnges from the
Jacyues-Cartier have been received at Paris directly,
dunng a complete Atlantic crossing (Bordeaux. to Panti-
ma), and even, at certain hours, when the shlp was in the Pacific.
2. The work of a $eating station .for the _forecasti.uy of
ocean weather.-In addition to the ship observations
which it collects, the Ja.cq.rtes-Ca,rtier has at its command
the European and h e r i c a n meteorological radiograms
received on board.’ Charts, sometimes more correct
over the ocean than over the land, cnn therefore be drawn twice a day on board, a fact which
of them by radio for the great trans-Atlantic routes.
Westbound shi s ex erience frequent, and rapid changes of weather, an$ sucf forecasts have for them a special interest. In the case of the fast eastbound liners, they
are not passed by more than one depression at most, even in winter. Bence it is sometimes possible to indi-
cate for them, as early as the time of their leaving port,
the broad characteristics of the weather changes for their whole voyage. The forecast service of the Ja.c ‘u.es-
Cartier has become shadily more popular at sea. %bus in bad weather it is not uncommon for vessels in the neighborhood to cease se.nding in order to 1iste.n to her
message; and frequently specipl forecasts are asked for.
It is the value of these forec,asts, based on tho modern
methods developed in France and Norway, which assures
the growth of the Jacques-Cartier’s ((station ” network, through its (( clients?’ for the receipt of weather forecasts
becoming its (( purveYors” of observations.2
The forecast studie,s on board of the Jacques-Ca:rtie.r
have advanced our knowledge of dyna,mic meteordogy. From these studies, the results of which will be resented
in due time by their authors, Mm. Coyecclue an! WehrlB, we may for the resent draw two general fundamental
conclusions: (1) t h e conception that the Atlantic Ocean
acts as a barrier (Qcran) [to the passage of disturbances
from North America to Europe], is no longe,r tenable; the progress of erturbations is continuous across the
AtIantic. (2) Tfe action of the polar front lnake,s itself felt at times down to the region of the Equator; the
trade winds are only approximately “ permanent.”
‘ increasing.
e working u of weather forecasts on. the spot. (an enormous technica P advantage,) and the broadcasting
~_________.__
1 Thesending from the Eiffel Toww,of mFages on very short wave lengths permitted in November 1834 the communication dlrect to the Jacqiua- Carttrr of the meteoro- logid situ& o& Euro
I Mention should be m s x a k o of the hearty cooperation of the U. S. Weather Bureau in glvin very efecient ubllaty to the work of the Jacques- Carttrr through the medlum of the Iklot Chsrts. $or two notes descriptive of t!? meteorolo~ral activities of the
gifg5-3 North Atlantic Pilot Chart for March, 1823, Storm and we8tht Forecasting
Atlantic Ocaan”. and for December 1924 “Meteorological Service of the Jocqute- Cart&.’’ The bulletidof the Nationd Re&?arci COFcil for Janunry. 1924, pp. lop, 101. contains a note by E. H. Bode on “The meteorolo@cal work of the Jacques- Carfitr.”- B. M. V.1
during the entire Atlantic crossing.
The success of the tests made by the Jacques-Cartier
has demonstrated the possibility and the utility of a service which shall coIlect observations and make fore-
casts for the Atlantic area. Since 1923 the International
Meteorological Committee has given its support and its official recognition to the project. The proper thing
now is to organize this service definitely through inter-
national cooperation.
HATTERAS DEPRESSIONS
By M. COYECGUE and PH. WEHRLB, National Meteorological Office of France
(Trmslatted from Conipfer Rendw. 179, No. 26, December 29, 1921, pp. 1617-1620, by B . M. Varney, Weather Bureau, Washington]
1. I’h.e.fmt.9, bmed on obsemintions on board the ((Jacques- Cn.rtier.”-The re ion off Cape Hatteras distinctly con-
faint nucleus of barometric depression appears, at first almost stationary. It grows, accompanied by the devel-
opment of a heavy A. St. Finally the Hatteras depres-
sion, with isobaric system fully formed, begins to move slowly toward the northeast, but does not reach normal
uelocity until it is opposite Nantucket Island. Opposite Newfoundland it turns definite1 ,toward the east, thus
along the polar front, properly so called), either mer ‘ng
Hatteras depressions affect almost the whole of Europe, nnd at times estencl into rather low latitudes. The are
around to northwest in Bmerican waters from Hatteras
to Newfoundland. The storm connected with the Hatteras LOW may traverse the Atlantic (e.g., January 8,
1924).
The frequency of the Hatteras depressions is of the
order of 30 per year. Their formation is almost entirely confined to the cold season. It always induces the move-
ment, out of the north or northwest, of an intense high- ressure center with a complete anticyclonic circulation.
h i e clepre,ssion appears along the border zone, between
the warm air current from the southwest directed by the Atlantic anticyclone and the cold current from the
easterly sector controlled by the moving antic clone.
ently, t 1 e depression being extremely weak (sometimes
even lacking a cloud system), and moving slowly from the
we,st to the region opposite Hatteras, where it begins rapidly to become more iiitonse. d secondary Hatteras depression tinil even sometimes a tertiary of decreasing
intensity, is sometimes related to the same high pressure
ce.n t er . 2. hterpretation,.-The strong hi h-pressure center es-
formation of the Hatteras LOW is due to the contrast
between the temperature of this air and that of the very warm tropical air above the Gulf Stream; hence the geo-
graphic localization. But in summer the polar air is warmed over the continent; hefice the seasonal locali-
zat,ion. Two types of Hatteras depression should be recognized:
(a) The LOW formed at the expense of the mother cyclone, which, as in the case of the April 19, 1922, cyclone, disap- pe.nrs. This type of Hatteras depression is characterized
by the pre,se.nce in its northern sector of a very clear line
of discontinuity (thus forming an extra front resembling
stitutes a birthp B ace of atmospheric disturbances. A
getting into line with the series o P polar LOWS (depressions
with one of the latter or maintaining its o m individua Y ity.
usually intense enough to cause gales from nort i east
The rocess may, however, develop somew t at differ-
sentially represents an invasion o f polar airll and the
1 See J. Bjerknes and K. Solberg, The Evolution of Cyclones. Memoir of the Nationd Meteorological Office of France, No. 8, 1824, pp. 95 ff.
JANUARY, 1935 MONTHLY WEATHER REVIEW 27
that along the [true] cold front), but separating two masses of polar air [which former1 constituted the two
which is relatively mild, and the new polar air from the
northwest, which is very cold.2 (b ) The parent cyclone persists (case of January 1’7,
1922). The northern sector of the Hatteras LOW is then made up of a homogeneous mass of cold air. This con-
dition of affairs, which is the most frequent condition, especially in winter, demands a powerful invasion of polar air, thus uttiiig an end to the series of cyclones in the
are produced in succession. If the invasion is lowerful
and B orm (in autumn and spring) an “Bntillaise.” The fact that the Hatteras depressions are young ex-
lains their lasting all the way across the Atlantic Ocean.
i o r n at the end of a c clone family, their trajectories
are able to come on shore in Europe at a lowerlatitude (unless the Azores anticyclone, by shiftin toward the
northeast forces them nearer Iceland). dways if they unite wit6 a polar LOW it is necessarily with the first
member of the next succeeding family, and hence at a
fairly high latitude.
In case where the ori inal depression comes from the
resembling a Mediterranean pseudofront hhe Pacific anticyclone being substituted for the Atlantic anti-
cyclone), or from a southern branch of the Pacific polar front, which divides by fission when it runs foul of a
weak continental anticyclone. 3. Contribution to general dynamic meteorology.-The h t type of Hatteras LOW is to be likened to the Genoese
de ressions. But in the case of the latter the cutting
o 8 of the warm sector (sec1usion)O is accomplished only
by the chain of the Alps; while in the case of the Hat-
teras depression it is the severed tro ical “root” of the
contrast m tem erature, whence we have a con-frmation
tend to fmor certain regions.
e is to be compared with the Mediter-
that the low tem erature of a mass of polar air crossing
summer, since the journey is an oceanic one. Further-
currents on op osite sides of the co 9 d front] of the parent
cyclone, name r y, the returning polar air from the east
family.s Pr nder these conditions several Hatteras LOWS
enou h it may even continue its progress toward t \ le south
in the nature of the case i? ie farther to the south, and they
west, it seems to procee % from a California seudofront
mother cyclone which is revitalized B y the effect of the
of the idea that t s e phenomena of regeneration of cyclones
ranean pseudo 9p ront. But in America, it is in winter
the continent is B est retained, while for Morocco it is in
The second t
1 This situation will be made clear by reference to J. BjerknPs and ?. Solberg, Life Cycle of Cyclones and the Polar-Front Theory of Atmospheric Circulatlon. Oeofysislie Publikationer, 3, No. 1, Krktiania. 1922. See especially p. 10, the right-hand diagram of Figure 6. See also the review and discussion of the above paper, by h J. Henry in Mo. WEATERR REV., Beptember, 1932,SO: 4-74, , The Figure 6 cited above is reproduced on p. 470.
I J Bjerknes and H. Solberg lor c11 p. 91 il.
4 [This name, which h u not: as iet,’acquired standing in meteorological terminology, team to be here applied to a northerly wind caused somewhat 9s the Texas “norther” is. Professor Talman suggests that it may be the “nortes” of the old Spanish nari- gatom in the Antilles.-B. M. V.]
I Bee Ph. dchereschewsky and ph. WehrW, Pseudo Polar Fronts. Comptes Rendus,
s h e . d!., p. 1618. 179,1924, p. 1185.
more, in America, in the abseqce of a center of action, the tem orary invasion by a moving anticyclone can give birt \ to only an occasional disturbance. In con-
trast to this, in the eastern Atlantic a polar invasion reinforces a great anticyclonic massif along [the border
of] which a pervisting control can function. In any case the building up of the polar front by the mechanism of wave formations opera.tes preferably in regions where special seasonal controls favor a seasonal development of the phenomeim In view of the analogy between the great warm and
cold currents in the western Pacific and the western Atlantic, it is not impossible that some of the polar
LOWS of America have their origin over Japanese waters
through a mechanism similar to that which causes the
Hatteras depressions. The Hatteras depressions may unite either with the polar LOW which comes immediately after their
cyclone. or with the followina LOW. They show pr% inte$erence of well develope2 and intense de essiom;
(2) that a wave formation may unite with .a gpession belonging to the next succeeding cydone famaly.
METEOROLOOICAL SUMMARY‘ FOR JANUARY, 1925, IN SOUTH AMERICA
[Reported by Seaor Julio Bustoa Navarrete. director El Yalto Observatory, Santiago, Chile]
The month was relatively rainy in southern Chile,
northern Argentina, and Bolivia. Cyclonic depressions were fre uent in the southern part of the Continent;
on the 7th. On the 21st an important anticyclonic center was situated off the Atlantic coast from Bahia Blanca and
the mouth of the Rio Negro: the maximum pressure at this time was 30.32 inches (770 mm.).
In general, temperatures were rather high in central Chile and on the Atlantic coast. Maximum tempera- tures of 104’ and 95’ (4 O O .C . and 35’ C.) were recorded
at Buenos Ares and Santiago, respectively. The lowest
tem erature observed was 29’ (- 1.6” C.) at Lonquimay
Electrical storms with rain and hail were rather
fre uent at La Paz and Sucre. h e c t o r Navarrete submits two weather maps, one each for January 7 and 31. The first portrays a deep
barometric depression centered over the extreme south- of the Continent with an area of high pressure over t e Pacific just west of Chile. This is the type of
cloudy, rainy weather in Chile. The second map presents a different pressure distribu-
tion, viz, R strong anticyclone centered over the Atlantic coast east of Argentina. This is a type of fair weather
with artid cloudiness in the central regions of Paraguay
at Punta ’b, renas the pressure fell to 25.94 inches (735 mm.)
in t P le Chilean Andes.
and 1 rgentina.