AUGUST, 1920. MONTHLY WEA4THER REVIEW. 465
moving from latitude 4 to latitude 41. Easterly velocity signifies the easterly componeii t of t,he rela.tive velocity of the body. The relative velocity is the init.ial velocity of projection, irrespective of direction. If the body is projected due north, its east.er1y velocity is zero a t the point of project.ion which is A in the figure.
As it curves to tlie eastward the easterly conipo- nent of the relative velocity graclually increases until when i t reaches C‘itsensterlyvelocity equals its relat.ive velocity. In the above illiiskation, the body moving from la bitude 50’ to 50’ 21’ acquires an easterly relocity in accordance
with the law of reservntion of areas of 5 meters per sec-
The easterly velocity a t -4 wn.s zcro. Hcnce a t latitude
50’ 24’ i t has acquired an increased ensterly velocity of 5
.meters per sec.ond but its relatiro velocity is unchanged. Continuin to move southward, i t loses it.s easterly ve- locity at and gains a westerly re1ocit.y rd 5 meters per seaond a t E, the most southerly point reached. Therefore a body mol-ing freely under the infiuence o f
the earth’s deflective force undergoes vnrint.ions in it.s easterly velocity in st.rict nccordnnce wit.11 the principle of the preservation of areas. Its rcla.t.ire ve1ocit.y or initial velocity of project,ioii remains unchanged. Thc
deflective force acts perpendiculnrly to the momentary direction of motion, causing t.he bocly t.o describe n nearly circular path with unchtuiged init.ia1 relative w1ocit.y. A body moving freely over tlie enrtll’s surfnce from onc latitude to another can and docs ohey the law of eclunl areas without any change in its relntiw w1ocit.y. At the estreme latitude wliicli it is able to reach in its curved path it gains or loses hv tlie law of areas an east.erly
velocity precisely equin-Jent t>o its init.ia1 velocity, if the direction of projection is along n meridian. I n the above quotation from Davis the term velocity is used in one sense only, meaning relatiw velocity. to Hadley’s teacliiii that 11 I J O ~~ mcn-ing
attain a reat velocity to t,he west. when it reached the Equator,%e makes the criticism that this laggin- cnii produce no eir‘ect on the velocity, meaning reyntive velocity. Hadley was correct in the sense tha.t. a cliniige of latitude involves a cha.nge in the easterly velocit,y of
a freely moving body, but he was wron in assuming
ond in excess o P that which it possessed a t htitucle 50’.
Ref toward e* in% t e Equator continually f ngs westward and vc:oiild
that a change in relative velocity wou f cl result. In
Davis’s illustration a body given a velocity of 35 miles per hour to the southward a t latitude 30’ would not even reach 1a.titude ?So, a fact which he omitted to state. In order that it may reach the eyuntor it should have an initial southward velocity of 116 meters per second, and at, the Equator it would he moving clue westward with it.s initial velocity. Thus moving air does not acquire the escessive veloci- tics implied in the est.racts given nhore, hecause it does not. niovc over the required range of latitude. The in- crease in eristerly velocity is checked when tlie limitin lat.it,udc is reached, hence friction is obviously not neede to reduce the excessive docities. I n order that. the body may cont,inue in its original direct,ion of project,ion, n force equal find opposite to the clellectire force must act. on the body. Assume that the hody moves on a plane wit.11 an inchnat,ion to the left of the tlircct.ion of Yject,ion. With the direction clue nort,h, the plane wi 1 slope to the west. If the inclination
o f tlic plane is such that the small c.omponent of ravity tciicline to dra.w the body down the pla.ne is q u a . B to the cleflect,n-e force. tlic inclination of the plane gradually increasing with increasing lat.itucle, the body will con- tinue moving in a clue north direction with uniform
velorri ty . The uniform motion of n boclj- on a.11 inclined plane is st.rictly minlogous to that. of air particles along straight isol)ms, wglecting frict.ion.
pressure to enstwnrcl. The air pnrt.icles will have a move- ment from sou t,li to north wit,li uniforni velocity under the eqnal nncl opposiite influences of the gradient tending t.o force tlie psrticles to the westward and the earth’s tleflcct.ivc? force tending to swerve thein eastward. It is obvious that. dlowin- for nn increase in gradient with iixrensing ~at,itude. 8ie conc1it.ion of steacly motion is realized and the air particles move over a wide ran e of lntitnde wit.11 uniform velocity. The principle o B the presermtion of areas is not thereby invaliclated nor is .it necesssry to assume that retarding or danipin influences
t. R e chan e of lntitude. The increase of relative easterly
velocit:\- !&e to increme of latibucle is esactly neutralized by the incrense of westerly velocity clue to the gradient.
2
Consider isohnrs estendin
nort.h nncl south wit,li low pressure to west.ward and hig E
o ernte to reduce the increased velocities ca 7 led for by
NOTES, ABSTRACTS, AND REVIEWS.
METEOROLOGICAL INFLUENCES OF THE S U N AND THE ATLANTl C.’
By Prof. J. W. GREGORY, F. R. P.
[Reprinted from A-utiirc (London). Aiip. 5, 1920, pp. 713-716.]
The rospects of long-period weather forecast.ing and the csp anation of major \mintions of climate a.p ear t,o rest on two lines of iiivestigat.ion. The effort of t ie first
is to connect changes in the weatelier with those in oceanic circulation; the second atkribut,es t.he changes t.0 qnria- tions in the heat supply of t,he sun a c h g through the atmospheric circulation. Each theory has it.s own a
priori probability. The oceanic. control of climate has
the attraction that eudlncenn is a potential refripernk)r. since it is a reservoir of almost ice-cold wxter, which, if
r P
-. . . .. . . . . . . . . . - . .
1 BJ6m Hellmd-Honsen and Fridt‘nf Nansen, “Temper2tiire \’arkitions in tlie North Atlmtic Oce:n and in the Atmospderc.” Intmdiictm $todies on tlie Cause 01 Vli- mitAo;icnl Varidtions. Smithsmi :n Miscellmeous coilwtiuus, vol. lxx., 12ihlirntioo 2537. 193. Pp. viii+lOS+?cl lates. Author’s abstract of orlginae work in Oermm, published in MONTHLY WEATUER REVIEW, April, 191Y, 46: 177-lis.
raised to the surface, must chill the air, disturb the winds, and ennlde polar ice to drift further into the temperate
seas. Hence Meinardus, for example, connected the range of ice in t.he Icelandic seas and harvests in Germany with vnrithms in t.he surfa.ce w-tkteis of t.he North Atlan- t.ic. The alternat.ive t,heory lins the recommendatmiion thlnt, since the et1rt.h receives its heat supply from the sun, v.ariixt.ion in solar activity is t.he natural cause of cliniat.ic clinnge. The abnor- mal cha.racter of some c.oasta.1 climates is clearly due to t.he upwelling of cold waber under t.he influence of off-
shore winds. Moreover, unusual spells of weather on some of the coast>s and islnnds of the At,lnntic follow changes iii the qutdity of its surfnce water, as proved by Dr. H. N. Uickson for Northwestern Europe, and by Prof H. H. Hilclebruiidsson’s demonst.rat,ion that for 15
years t,licre hns heen constant coincidence between rain- full in Brit.ish Columbia and the \veatrher in the following auturiin in the -4zores. The alternative theory that the
The occnnic t.he0r-y must be true in part,.
466 MONTHLY WEATHER REVIEW. A%UOUST, 1gu)
main factor in controlling the temperature of the eart.h is the varying heat from the sun acting through changes of wind and atmos heric pressure has been mainly nd- vanced by the wo% of Sir Norman and Dr. W. .J. S. Lockyer and of Prof. Frank Bigelow: they arc nom stronolv reinforced by Dr. B. Hellaiicl-Hniisen. the direc- tor o r the biological stat.ion at Bergen, and Dr. Nansen, who remark that these views have 1iit.hertn received hut little support. The important memoir hy these Nonvegkn oceanogra- phers is based on a detsiled stuclv of snriat.ions in t.he temperatures of the air and surface wat,ers slow t.he -steamer route froni tlie Enali+ iaiiiiel to ~e w Fork. Their detailed discussion CJ? tlhh, Ylesults and associated problems is acconipanied by a vdualile series of tempera- ture charts of the North Atlantic for the nioiitlis of February and March from 189Y to 1910. The c1at.a are
often uncertain, and t,he inconvenience of the cent,igmde thermometer with its zero tit freezing point is illustmt,ed
b records of water temperature of -3’ C!. and -4’ C.,
Nansen, after discussion of t.he theory of oceanic contml,
reject i t as quite inadequate. Thus the cIiilling effect of the drift of ice into the Nortli Atlniitic theg est.imi1t.e ns
“ vanishingly small ” in comparison wit.11 t.lie heat t,mns- ported by the air, or even by ocean currents. They consider that, though not yet Iully est,a!:lishecl, the rnria- tims of tlie air tcniperaturc preceded, and were t.herefors not the result of, those of the water t,eniperii.t,ure. They hold thiit the vaiint,i;>ns of t,em erature require some
variztt ions. Faith in the meteorological influence of c?cea.uk circu- lation was greatly favored by the esaggera.ted cst,inia tes attached to whttt the authors refer to 11s “the so-c.nllec1 Gulf Stream.” Thus the warmt.h uf the vsatcr off thc Nor,vegian coast wits attributed tc) that current, e ~e n by
Pettersson and Meiuardus ; this cniiclusicm the authors describe as surprising because t.he evidence of saliniby shows that the Normginn waters are cc;a.stal tmil quit,e dizerent from those of the mitl-ht.lant,ic. This sound criticism oI the Swedish aiid Miinster oce~tiic~)gra~~liers renders i t the more remarkdile that t!iere is no refrrcnce,
either in the long Iiiiatorical discussion or in t,he i )ii)li:)grii- phy, to the pimeer wwk on t,liis suhjert, in tho e:trliw papers by Dr. H. N. Dicksim, or to his ohservat.i.-)iis ns te.1
the seasoiinl entrunce of the Atlantic. water itit.!> thc North Sea. The authors agree with Ychott in terniinnt.ing the Gulf Stream west of Newfc~unclland, itiicl cdling the current off Western Europe the “St,laiitic current.,” for w1iic.h Diclison’s name of “ European cyrrcnt ” is morc descriptive and definite. The Atlantic !s u, large mass,
and has a whole s.vsteni of currents, of which the so-called Atlantic current is by no means the largest. Drs. Hellancl-Hansen ani1 Nansen, after rejectzing the oceanic theory, accept as firmly esta!Jished the depend-
ence of vrinations in the ottrtli’s tem eratures on the solar
proniiiieiices, and terrestricil magnetic disturhnnces. They
point out that the iiifluencc of the sun on thc weather of
any area on the earth depends upon so coniples n series nf
factors that the results t1.t first, sight nppetir incmsistent. The crude espectat,i:m that an increase of heat su ’ply
elrth was early dismissed, for tlie greater cvnporati!m
wauld lJwer the temperature on the const lands by in- creased clouds, rain, and snow. Blnnford pointed out,
for esample, the see-smv of oceanic and cont.inental con- ditions; but, though his view has not been fully con-
w K ich have to be rejected. Drs. Hellnncl-Bansen and
much granter and more genera P cnuse tlian oceniiic
varintinis proved by sun spots, t. F ie iiumbeiu of s :h r
froni the sun would raire t.he temperature of the w 5 iole
fiimccl, his principle is supported by the proof that regi:,ns are o positely affected by chaiiaes in the heat supplv from t f ie sun. Bigelow has divide2 the world in to three groups of rezions: In the “direct” group tshe tem- perature coiirlit,ions vary directly mi th the sun; in the
“ iniiirect ” group the raiiat,ions agree in time, but are opposite in c1inr:i.cter: in t,he third, the I‘ indiff ereiit” groupq there is 110 regular correspondence. Sir Norman niitl Dr. W. J. S. Locliyer have shown that a region may for years belong to the ’’ direct” group, then suddenly
become i*indirectq” ant1 later return to tlie “ direct” group. Drs. Hellnncl-Hnnsen and Nansen accept this frecluent inversion, and also their esplanation of tlie
phenomenon. The author’s instructive study of North Atlantic tem- perntnres therefore s trengt,hens t,he case for solar varia- t.ions act.ing t,lirougli t.he atmospheric circulation as the ni:lin cause of meteoroloaical changes. To what es tent
t,he oce:ui helps by regu’lnting the air temperature and circul:i.tion t,he nuthors clo not discuss in the resent
aft cr further iiirestigatioiis in a series of memoirs to which tlie present is introtluc.tory. The usefulness of the promiset1 memoirs would be increased (should they have
RS ms.ny nppcndicc.s and supplenientary notes as the
present) if each were provicled with an i d e s .
memoir; that and other questions are to be den P t with
SERVICES OF A VESSEL-REPORTING STATION OF THE WEATHER BUREAU.
The following account of tho grounding of the Dutch S. S. d m k m on hiigust. 29, 1930, netir Point Reyes Light, Chlif., has heen furnishcd by Mr. J. C. Smith, in cliargc of t.hc .wssel-rcporting station of the Weitther Bi.ireau at t.1i:i.t place. It is publisliecl as an illustration of the srrviccs lwing rendered 1)y the Bureau a t vessel- rcport,ing s t,ia t ir ins. The A IW 7ia 12 was subsccluen tly re-
Aoiiteil and tirrivrd n t San Francisco on September 1.
The damage sustainecl! if tiny, is not known. The offic.ei-s of the Ar111:m havc for marly years cooperated
with t,he Burenti in marine workl a d .the news of her niisfort.uno was received with regret.
(:)~i .\iigust 29, 1920. at. 2 p. ni. tlie Ihit,ch S. S. d m k n n , 5,000 groRs tons. wit.li mrgo of sugar aiid ruldwr. bound from Ratuvia for San Francisco, sent agroiind almit 6 i d e e north of this etstt,ion, during a C I V I ~J ~~ fng. P. (-). S. cxlls resulted in tugs being dispatched from Pan b’rancisc-0. HI wever. they have nnt siiweeiled in pulling the veseel
nff. The vessel’s wirelesa outfit €ailed on the 30th. and as a result. this ofice ~a e called upin for consideralJle information by maritime intcrests anrl newspnpctrs of Pan Francisco. Weather and sea con- ditions were inquired aliout frequently: also. topographic conditions in tile vicinity of the vessel. An aeroplane was dispatched from Pan Francisco t,o the scene I i f the wreck on the strength of information given ]I\, this otficr. Iinless tlie vessel is pulled off the sand within
a Hlinrt h i e i t niay break amirlship, resulting in the lwa of the vessel as well aa the valualJe cargo.
This office remained open day and night durin the critical stage
answering inquiries by long-distance telephone.-$ G. T.
FIRST SCIENTIFIC CONFERENCE, PAN-PACIFIC UNION.
ZTnder the auspices of the PawPacific Union a scientific coiiferencc for tlie purpose of outlining n plan of esplor- ing tlir Pacific Owan was held at Honolulu, Hawaii, heginning hugnst ‘2. niid eliding August 20, 1920. This
conference hrought together n few more than 100
scientists from the countries bordering on the Pacific Ocean. The United States, Australia, New Zealand, Japan, niid the Philippine Islands were well represented.