The Rainfall of the Northeastern United States
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JANUARY,1915. MONTHTS WEATHER REVIEW. 11 eastern slopes (except in Vermont), and the eastern shores j : I. of t,heGreat Lakes et niore snow t!hnn the western. THE RAINFALL OF THE NORTHEASTERN UNITED Snow generally fa4 Is in connection with winter c.ycli’ncs, STATES. for the cyc,loiiic act.ion and the effect of to ography on the winds cause precipitation. As the norti! east wincl is Iiy B. 0. WALLIS,B. Sc. (ECONOMICS).F. R. C;. R., F. S. S. both cold and damp over prrtctically the whole e.ais .. t ern [Dated: North Finchlcp, England. Sept. 21,1914.1 United States, it is the wind of the goat snowst,orms. The northwest wind, although cold, is genernllv dry and THE METHOD OF INVESTIGATION. so brings, at most, only snow flurries esccpt, ’locnllr 011 Probably the two most iniportant considcrat,ions re- a windward mountain slope or in the lee of t,hc Grent ga.rding the rainffill of any area are its total quant,ity Lakes. In brief, the nia.in factors w7hic.h control snowfall aiid i t.s distribiibion through tho year. Attenhn is are ten1 ersture, moist-ure in the air, esposiiro to moistm called in this pn.pe.r to the second c.onside,rat,ion,and n.n winds, focnl topography, and the pnssagc of win t.cr n.tt.enipt,lins been made to measure the distribut,ion by cyclones. mmns of the statistid niothod of tlifferenccs. The REFERENCESAND NOTES. nniount of rainfall which would be prccipit>at.d n.t n (1) &e also American Almanac for 1837, p. 169.-185: “Notiim of givm plsce, upon the n,ssumpt>iont,hnt such rainfnll were remarkably cold winters.” evenly distrihu ted through the year, hss heen taken fi.s (2) Some other journals with less extensive record@are: n 7~0~)~.This nom. is obtained by dividing the total Cleaveland, Parker. Results of meteomlogiral obsrrvat.innr; matlr nnnual fall hy 365, and by niult.iplying tho quotients by at Brunswick, Me., 1S07 to 1S57. Caswell, Alexis. Resulta of meteorologicd obrervatin~isn;;id~ :it 2S, :jO, a.nd 31, respert,ively, to obt.nin the numhcrs Providence, R. I., from December, 1S31, to May. 1SBO. which rcpresent the nornis for t.he niont,li of Februa.ry, Hill, Leonard. Met.coro1ogica.land clironological register. IPDfi lo and for the 30- and 31-c1a.y mont.hs. The dueof the 1869 at Enst Bridgewater. h.iw. Plymouth, Mass. 1PIi9. norm 11a.s been tdwi for each iiionth for all places as (3) See J. P. Espy’s reports in the Journal of the Fm.nklin Indtutp, 100, so 2-5, 13-”’-3) Philadelphia. 1839 to 1811. t,liat in t,he accompmying maps (figs. , (4) See Report of the Smithaonian Institution for 1855: Directions for meteorolo ical observations, adopted by the Smiths0nia.n Institution for the ~irst-fiwotmervere. (5) U. S. Weather Bureau. Annusl report of the Chief, 1891-93. Washington, 1893. p. 147. (6) A history of meteorological ohervations in the United State8 is attempted by Marcus Benjamin in the work ‘‘The Smithsonim Institution, 18-18-1898’’ (Washington, 1697) on pp. 647-678. More comp1et.e details are gven by various authors before t,he International Meteorological Congress, held at Chicago, Ill., August 21-24, 1S93. (&e U. S. Weather Bureau Bulletin 11. pp. 207-220, 82-302. ) (7) Volney, C. F. A view of the soil and climate of the United States of America. Translated from the French by C. R. Brown. Philadelphia, 1804. (8) Blodget, Lorin. Climatology of the United States. and of the TemDerat.eLatitudes of the North American cont.inent. Embracing a full coi )arison of these with the climatology . of Europe and Asi: . Incfuding a summary of the statistics of meteorological oheer- vatious in the United States condensed from recent scientific and official publications. Philadelphia. 1857. xvi. [17]-536 4’. An appreciation of this monumental work will be founfin the MONTHLYWEATHER REVIEW, January, 1914,42: 33-27. VIG. L-Anniial mar& of,phiviornetrieeocfficients for Michiran. Ohio Valley, nnd 1.h~ (9) S. Weather Bureau. Rainfall and snow of the United Statrp Piedmont compared with the anniral march of the temperature onomnlirs for the U. oorthenstcru I’nihl Sf.ates. ascompiled tc, theendof 1891, withennua1,seasonul. monthly,and othw charts. Teat and Atlas. Waahington. 1894. 80 p. 4’. Atlas: 100 23 charta, 18 x 21 inches. the line which is marked indicates that the rainfnll This publication is reviewed in Amer. meteorol. jour., Tlcxrtnn, n.t all places along th8.t line is the norni for thc month. Mass., June, 1S95, 12: 71-2. Differenccs from the norm are cs resscd as percentages. (10) Henry, A. J. & others. Climatology of the United Ptaten. Su pose the norm for n given pace for R’aahington. 1906. 1013 p. 33 pl. 4’. (U. 8. \+‘rather Dureau F bulletin “Q.” W.B. no. 361.) inc! es, sncl the actual average rainfall at (I!) See MOXTHLPWEATI~ER REVIEW, Wa~hington, June, 1914, 43: Januniy is 3 inches; then since, when 2+==100, 3=130, 318330. the difference for tshat place for January is 130, which (12) U. S. Weather Bureau. Summary of the climatolngiral data implies that during January at that place the precipita- for the United States by Sections 106 [sertions). Printed at various 30 cent is section centera. 1908-1912. var. pag. 4’. (Bulletin “W.” W.B. tion is per above the nomi; i. e., January n no. 476.) re1ativ ely wet m ont,h . (13) Such an effect is clearly shown on the IT. 8. Weather Bureau The ntinie “ pluvionictric coefficient ” has been given “Snow and Ice Bulletin” for December 30, 1913. to t,liis qua.ntitative expression by Dr. A. Angot, who (14) For a thorough study of the physird rhaiigccl whirh take placc is responsihle for tallis application of t.hc method of in a snom-cover. See - Jansson & Westman, J. Quelques rerherrhcn Hiir In rnurcrtiirc rliff ewnces to rainfall studiss. When pluviomctric de neige. Biill., Geol. instit. of Up~ah,1901, Nn. 10, 5, pt. 2, pp. ?::I-- coefficicnts are inrlicated upon iiiaps, u 1011 the same 260. principles as isohyets, the lincs of equal c opnrtiire from (15) See MONTELY WEATRERREVIEW, November, 1911. 39: 1671; I alm Chart VIII in the REVIEWfor November, 1911. the: rainfall norni have been called by tho present writer (16) The United States Forest Service ofirial liring at an altitude ol ‘I equipluvcs,” using a Latin term for the sake of greater 5,060 ft. on Mount Pisgah, N.C., 18 miles eouthwst of Asherille, N. C., ~- rwently told the writer that the snow accumulated on the ground. 1 Mr. Ernest I;nld (I) has pointed out that the ‘*pluvlo,metrircoollicient“ is “the ratin of the illsin daily rainfall01 a particular month to the LuBan daily rninlall of the mmetimes to a depth of 3 feet, and that in one niqht a snowfall of 27 w-hole yrw.” inrhes occurred. The similarity between these extremes and those The term “isomer” ha< been suggested bv Jfr. G. Mkr (4j in place of t.he term met in eastern Massachusetts, suggests that the average snowfall in the %quiplure” coined by Nr. WdLIL. If the former term is used one should be csreful to prelaee It with !he word “rsinlall” or “precipitatim.” since in itself ‘*isomer”does southern Appalachians may be about 50 inches annually. not suggest a quality of rainfall. This disnlvantaggo Is absent from the term “equi- (17) Greely, Adojphus W. American Weather. 11. 16. p1uve.”-[c. A., jr.] Unauthenticated | Downloaded 09/29/21 10:21 AM UTC 13 MONTHLY WEATHER REVIEW. .TAXTART? 191 ;: distainctaess. The accompanying maps show the equi- Sup ose we divide the places of which there are luves for the several mont,hs for t,he nort,heast.ern rainfa R records into three classes: ((r.) where the records enited St,ates. have been lie t for from 40 to 50 pears, (b) where the Eqzri. ~Zwtwin. eoiihnst with isof, yefs.-I t has been laid records have Eeen ke t for from 20 to 40 years, and (c) down th at monthly rclinfall maps, where the rainfall is where records have !,en kept for less than 20 years. indicnted by means of isohvets, are of little value unless When the maps are under construction, all stations in (1) the observat,ions have been taken over h. long series class (a) will be entered first, and the general run of the of years, which should approsinlate t.o 50, and (3) ob- equipluves can then be determined; stations in class .___-._.-,-.I -..i-- -.\., J .r January. Fro. 2.--Equlpluves for the northeastern United States lor the months 01 January, Febnrarp, and March. (b) will nest be entered in all those cases whore the values are in general harmony with the run of the equi- pluves; and stations in class (e) will be used to determine the run of the equipluves when other observations fail. In figures 2-5 accompanying this pa Ier the “aqui- luves” are drawn at 30 er cent intcrvafs, and it rarely gappens that places in cP asses (b) and (c) cliffcr by more than 10 per cent from the general arernge vdues of surrounding places. Consequently, in nctual practice, April. May. June. PIO.3.-Equipluves lor the northeastern United States for the months of April, May, and June. coefficient,s snioothes out the ac.c.identd rain-s lashes, most of the records can be utilized directly without. and at the same time it t,ends to brin the values o6 tnined resorting to mothods of interpolatlion.