242 MONTHLY WEATHER REVIEW. MAY, 199.2
moved slowly eastwa.rd, although there were fresh south- west winds aloft to the west and southwest, and on October 39 and December 21, 1920, a.nd January 2, 1922, when there was a deep stn,tiona.ry cyclone over New- foundland and the winds aloft over t,lie northeastern States were stron northwest. All of these 5 anticy-
It is quite interesting to note t,hat, when Alberta or Manitoba anticyclones reach the eastfern Stakes wit,h major axis north-south and fresh to st,rong southwest winds set in aloft, say from Oklahonia nort,liwarcl and north-eastwnrd, but remnin only niodernte southwest nloft over the Gulf Ststes, the direction of the major asis is jnvariablp shifted from nortli-south to northeast- southwest, the southern end remaining almost fised in osition, i. e., pressure decreases rapidly east of the upper kississippi Vnlley and a cyclone nioves eastward over this region, while the bnromet,er falls very slowly over the southeastern States and generally rises a t Hamilton, Bermuda. stti-
tionnry cyclone in the vicinity of Newfoundlunx, the northern end of the an ticyclonr will disappear entirely (see niap of Feb. 15, 1931). This condition is peculiar to anticyclones thu t move sout.lieastward from Alberta or Mamtoba.. One anticyclone, thnt of December 30,
1921, was originally tabulutcd as of Pwific origin, but being the only one, R further investiaat.ion wtis made and it was found that, while it origindly appeared on the Pacific coast., i t was reinforced from the Canadian N0rt.h-
clones moved slow K y.
If, at t,he mine t.ime, there is a dee
west on December 28, thereafter partaking of the nature of an Alberta anticyclone. It has been found from previous observntion and from this study that whenever n Pacific anticyclone is reinforced by an anallobar moving down from the Canadian Northwest it becomes an Alberta anticyclone in fact; furthermore, if either a
Pacific or an Alberta aaticyclone is reinforced from the Hudson Bay region its future course is the same as if it came ori ’nally from that region.
anticyclones was very deep and controlled the upper winds far to the westward. A striking example was the anticyclone of the last week in October, 1921, the note made in connection with it being as follows:
October.’5.-Anticyclone 30.3 [inches] over Ontario. hfoderate to fieah east and soiitheaatwivinda aloft from Lsnsin and Royal Center westward. Gentle muthwest winds in west Gulf &&XI. Anticyclone moved slowly southeastward over northeastern States, then remained etatior?- ary with lessening intensity until end of month. Stationaq cyclone over Newfoundland. Winds aloft remained southeast to northeast at Royal Center dnring entire peTiod and two Colorado disturbances of marked intensity were retarded, partially filled up, and diverted from normal path.
As a result of this study and of the day-to-day ex- amination of the aerological charts the writer is con- vinced that, given sufficient upper-air observations, the forecaster can predict with a reat deal of confidence the
every anticyclone.
It wil Y be observed that each of the five stationary
future course and the rate o 5 movement of practically
HIGH-LEVEL ISOBARS AS USED IN EVERY-DAY WEATHER SERVICE.
By RIKICHI SEIIGIUCHI.
(Cambridge, England, Apr. 5,1922.1
NoTE.-ThrWgh the courtesy of Prof. V. B prknes, Doetor Seklgurhi has Nndly ppared for the REVIEW the paper which he delivered before the Internatlorid Com- m don for the iuvevtigation of thq Upper er held at Bergen,, Nor\vay. July %SO, lW,l
Doctor Sekiguchi has had extensive experience 111 the application of maps of frtwir pressure 8 to forecasting in Jspan.-EDrTOR.
The present conimunication is a short summary of the author s two years’ experience in his weather service, in coo eration u-it.h Dr. S. Fujiwhrtra and Dr. Y. Horiguchi, a t &aka and Kobe. Several t,risls in the use of higli- level isobars were made with the hope of finding some help for predkting the change of westher type with greater certainty than the ordin synoptic charts alone
level was chosen for daily use and proved itself very useful in redicting movements of cycloiiic. centers. Later on, c E arts for the 3,000-meter level were added to the scheme and even 6,000-meter isobars were drawr, occasionally. But after some ex erience having found
can afford. A t first (the spring Y o 1918), the 1,000-meter
the 3,000-meter chart most usefu P , the author confined
At first the corn lexity of the trend of the isobars as
But as the author be- influenced by loca P abnormalby of surface air tempera- tures was a perplexing feature.
came somewhat experienced in this method he could et rid of this complexity to some extent by making h e allowances for the abnormalities that might be estimated to some degree from the to o raphic conditions, tem-
study it has been found that the general trend of the
upper isobars in eneral was not so much affected by the actual lapse rateseing unknown as it was at first feared. The remaining nbnormalitiea seemed to have caused no great disturbances in considering the general trend of isobars in the majority of cases. Moreover, for the sake of safety, the high-level charts were based on the data from coast .stations only, as far as it was possible, in view of minimizing the effect of surface inversion. Some of the results of investigations are summarized as follows:
(1) Tho movements of cyclonic centers in the Far East showed in most cases fair accordance with the general trend of the 3,000-meter isobars? showing the less de- pendence upon the trend of sea-level isobars.
(2) The re ion where the general trend of both systems
each other was never assed b a cyclone which hap- ened to be in the neig K B borhoo at that moment, This fact seems to be in fair accord with the current idea that cyclones tend to be drifted by the prevailing upper-air current, if the upper isobars are assumed as identical with the stream lines. on that level.
(3) When both systems of isobars ran nearly arallel on three sides-that is, on the front, right, and P eft-of the path of the cyclone, that cyclone was observed to be generally stationar . Similar phenomena were almost invariably observecf when. the wedges of high pressure
perature changes, the state o 71 t e sky, etc. After some
of isobars ( H ree-air and sea-level) ran nearly parallel to
~~~ ~
Mr. C. L. Mitchell points out numeroua iddar
-
where anticydtmia movemclllt in the United States was in ywmeut with the direction and speed of upper nurenla. This REVIEW, pp. 241-242. DITOR.
MAY, 1922. MONTHLY M7EATHER REVIEW. 243
areas pressed upon the front of the cyclone from both sides of the track. The space between the wed es was called
ency to move toward the “gate” but could not make any remarkable advance as long as the “gate” remained shut; it rushed through as soon as the “gate” was opened.
(4) Most cyclones showed decided tendencies to move toward the region where unmistakable cross-intersec tions of upper and lower isobars could be perceived. These crosses” also indicated the weather declining there most rapidly, while in the r ion of “parallel” the weather
(5) h o different classes of “crosses” have been dis- tinguished: One, indicative of a lower drift, turned 90°
counterclockwise from the direction of the upper drift, and the other indicative of the opposite turning. The cyclone-attracting tendency of the ’ crosses” was shown only by the former class, while the latter indicated the weather clearing up. The former class, however, did not show its full effect unless the upper drift seemed to be of The former was sometimes referred to
formed a t some distance.
(6) As a result of statistical study it was shown that movin anticyclones in the neighborhood of Japan have
prominently appear the “crosses” on the rear of them. (7) By means of the isobaric charts for successive hei hts the thickness of antic clones has been estimated,
persisted fairly long, while very thin ones faded away in a short time. (8) The observations of pilot balloons generally showed fair accordance with the trend of upper isobars except when the station (Kobe) happened to be near the point of shar recurvature of isobars.
(9) #he existence of the surface of discontinuity has been indicated and its height a t the oint of observation
vations. Sharp bending of the trajectory attended by sudden change of wind s eed has been taken as a sign of
Shortly after such a surface of discontinuity a chan e
perceived, especially when the abrupt change of wind direction from some easterly point to southwesterly point a t some h ’ ht near 3,000 meters was observed. Steady
taining those directions u to several thousand meters
persistence of anticyclonic weather. (10) In the colder season, so long as the general trend of the up er isobars in the East China Sea and the Yellow
the eneral weather conditions in Japan were goo: and stea d y. As the weather declined they gradual1 changed to horizontality-that is, west to east trend. dnally the trend became directed from some southwesterly oint to
east coast o 7 China. The whole appearance of the chart of upper isobars gives an impression of a wavy system movmg slowly from west to east. In many cases watch- ing such movement was very helpful to the author in saz’
(3 &arly o posite directions of upper and lower isobars during &e winter monsoon rays in the East China Sea should be taken into account in the ex lana-
simply by the orographic effect. The fairly strong and
(‘the gate of the cyclone” because typhoons s 7l owed a tend-
usual1 continued to be 7 air.
successful warm O r i P . y as the reliable foreteller of a cyclone being
genera f tendencies to move the more rapidly, the more
an d it was found that very t ll ick [vertical depth] HIGHS
fixed with fair accuracy by means o P pilot-balloon obser-
transition between two li stinct drifts, one over another.
from anticyclonic to cyclonic type of weather was usual f y
northwester Y y, northeasterly, or southwesterly winds, re-
without any remarkable c I! ange, seemed to suggest the
Sea was P rom some northwesterly to southeasterly oint,
northeaster1 as a continental cyclone approac R ed the
u on the first sign of cyclonic approach.
tion of that phenomenon which was formerly exp P ained
steady southwesterly wind revailing thereabout (and
with the upper and lower isobars in the same direction, does not generally bring about continued rain like that of the winter season.
(13) There have been many instances of heavy rain which can be suitably explained only by supposing the existence of instabilit that may have been arising from
shown by the trend of up er and lower isobars. Thus I have summe1 up my esperience briefly. Reflecting upon the method used, the weakest point lies in the uncertainty of the hpse rate. Notwithstanding, we have proceeded with our eyes closed to it, for a while, in eagerness to raise the percentage of successful fore- casts on any reasonable ground, leaving furt,her refine- ments and improvements of the method to later investigations.
also along the Pacific coast o P Japan proper) in summer,
the invasion of a col B drift of air over a warm one, as
DISCUSSION.
American meteorologists will appreciate this generous act of Doctor Sekipchi in pausing from his bus
casting from free-air isobaric charts, as determined by Japanese experience. The intrinsic merit of such charts which represent (when accurately drawn) red conditions, in contrast with hypofhetieab conditions shown upon the sea-level charts, has long been recognized. But the difficulty of correctly estiniatin t,he temperature con-
sea-level as a reduction plane, it being much easier for us to have faith in the temperature of an air column which does not esist than in one which does, when actual measurements are not possible. We have chosen, rather, to “bear those ills we have, than fly to ot,hers, that we know not of.” But the accessibility of aerological data in constant1 increasing quantity has given rise to an unmistakab e tendency for forecasters to give attention to free-air conditions, with a view to adapting the information thus gained to the improvement of t,he current forecast. In a
country so large as the United States, where so many influences are operative, it is far from easy to read at once the significance of these free-air henomena. This prac- tical message of Doctor Sekiguc R i comes, therefore, at once as a c.hal1enge and as an encoura ement to those who
The process of collecting aerological information at numerous well-distributed stations is an espensive one, and the desirability of basing the free-air map u on surface conditions is apparent. The method use% in Japan is clever; but, as Doctor Sekiguchi shows, it is chefly a plicable to the stations subject to marine influ- ences. P he short distance between the stations on the east and west coasts of J a an enables one to draw the isobars
show the effects Qf an incorrect temperature ar ument.
culties so easil , because of the relative paucity of, and eat longitu cip mal distance between coastal stations. !%e problem is to find a way that wid satisfy our needs. Doctor Sekiguchi’s paper, while perha s not offering a
to our work, oes remove, in a lar e measure, whatever anxiety we niay have had as to t e usefulness of such charts and allows us to concentrate upon producing some- thing that will help us as much as the Japanese maps have helped the forecasters at Osaka, Kobe, and Tokyo.- C. La Roy Meisinger.
pean visit to commit to writing these precepts 7 or Euro- fore-
ditions in the free air has led to t i e general acceptance of
T-
look to the free-air for forecasting ai zi s.
without giving much R eed to the interior stations, which
But we, in the United States, can not escape t % e diffi-
group ofprece ts that we can take over % odily and apply
P B