APRIL, 1915. MONTHLY WEATHER REVIEW. 179 -- Highest. OF. 91 90 .w fir, <5 s9 m 91 91 91 91 91 ' modified by its proximity to the ocean and the rev% lence of the alternatino land and sea breezes. Altgough north of the E uator 8ie highest day temperatures occur in the period Becemher to May and the lowest during July to September. Night teinperat8ures are fairlv uni- form throughout the year eliceit for January and Feb- remaining niont81is, probably on account of increased radiation clue to absence of clouds aiicl the drier condition of the at,inosphere. January has tlie greatpest range between tlie day and night temperatures whilc the least occurs during the The mn.siaium teinperntnre i;id not go higher thnn 010 nurinu the entiye eriocl of 20 months observations and reache8 t h t point r >ut S times. Mininiuin temperatures range w+t8hin n few degrees of 70' throughout tlie gear, escept froin December to Feb- ruary, when they occnsioiinlly fall helo\v 60'. A niininiuni temperature of 66" on tmhe night of December 8, 1913, is referred t,o by the obsermr as a very cold night although in the following Janunry readings as low as 5s' were recorded. The unusually low temperatures during these months are reported n.s occurring with dry north winds probably blowing from the Sahnrn. although their dry charact,er is doubtlrss much nioclified during their passa.ge @Fer the intervening forests. ruary when they are considerah !I y lower than during the eriod June to Septeinber. Lowest. -- O F . 0s 69 I% 51 70 fifi 5s A5 68 m 2 The characteristic wet and dry seasom of the Tropics are well defined in this section of the African coast. January probably has the least rainfall, only 0.10 inch fallin durin that month in 1914. December, Februar , and a 9 arch 11 -ewise appear as months of light rainfall, t x e total for the four dry months constituting less than 3 per cent of the annual. The wet season prevails froni May to November, during which period rains are frequent and often heavy, as much as 6 to 8 inches falling in n single ieriod of 24 during the same months of cliflerent years; for instance, June, 1013, had a total of 27.4s inches, while the same month of 1914 had slightly inorc than 50 inches. The total rainfall for the 12 months, July, 1013, to June, 1014, was niore than 300 inches, a record probably equal to that of any otlher point along the coast. During the rniuy semen p p i t a t i o n is of almost daily oc.c,urrence, and clou y weather prevails con- tinuously for long periods. Froin July to October, 1913, inclusive, 123 clays, rain occurred on all but 17 days. During the drier eriod of the year there is much clear occur a t regular periods, the land breeze from about 11 p. m. to about 9 a. ni. and the sea breeze for the reilzain- der of the 24 hours. hours. Considerable variation esists in t t ie amounts and pleasant weat I: er, and tvhe land and sea breezes 1913. JUUE ....................................... Julv ....................................... Au&t .................................... September ................................. October ................................... November ................................. Dmmber ................................. 1914. May ....................................... I-----, ... -- .I-- OF. ! OF. .W.n 8 i .i iS.1 55.3 ,I . I Fc3.4 77.0 81.7 i6.G 81.7 iS.6 84.5 79.6 813.6 i9.9 R7.S -- ~ -- Si. 5 8:. 6 s3.2 X i . 9 Si. 3 W. 6 3 .3 .so. 3 81. 6 S3.6 55.0 S5.2 Temperature. .... -__ Nean mlnl- mum. "F. 72.3 i?. 1 i?. 0 72.3 71.6 8 .6 72.5 n. 0 9 .2 ,n. 2 i?. 0 51.8 71.6 73.3 71.3 71.8 73.1 72.6 i?. 4 71.5 MONTHLY WEATRER PERIODICITY .I By VLADIMIR K~PPEN. [Translated from 11Ieteorolo+Aw Zeitschrift. April, 1815,W : lSI)-1855c. A., jr.] It is wonderful witsh what stubboriiness does persist the belief t1ia.t tlie moon niust in some kind of a manner exer- cise a decisive influence on the weather and that the wicked, naiTow-minded sc1ioln.r~ simply refuse to recognize it. It is claimcd trliat scholars refuse to investigate t.he matter, contenting themselves with discrediting the statements made by t81ie "Unbiased" who do not belong to the profession. 1 PrelImInary communication; the fiill memolr will appear in the ArcAiv der Deut- lichen See.Wnrta.--AUlhm. Creates1 dally Wrn OF. 21 16 14 14 17 1.8 22 31 24 21 19 20 15 12 17 13 14 17 2s is -- Mean dally range. 'F. 15.4 13.2 11.4 9.4 10.1 12.1 14.1 15. R 18.7 17.8 16.3 16.3 15.6 9.3 8.0 8.9 9.5 11.0 12.6 lfi. i - Total. Inches. 9.93 27.4.9 30.69 30.07 23.90 24.35 8.74 1.74 n. i o 1. s4 1.3 8. i 6 19. ;o .w. 35 13.25 14.48 26.43 31.66 1 3 .0 4.43 Precipitation. Grestml In 24 hours. InchFs. 2.53 4.38 6.24 6.1R 3.06 4.52 2.35 0. i 4 n. i o n. a- 1.54 2.43 3. s5 7.50 3.20 2.95 3. n4 4.02 :: g Number ofda s D.01 inch or more. W1t.i - Day#. 17 24 29 25 26 26 15 4 I 1 6 14 23 29 33 3 28 30 23 8 .- __ -.- Clear. Days. 8 1 0 1 S 13 7 13 16 15 15 25 8 5 3 6 I3 5 I2 14 Partly cloudy. - Days. 14 4 11 9 14 17 11 10 8 8 5 22 13 6 9 14 14 14 15 n Cloudy. Days. 9 25 31 17 l f i 5 fi 7 5 5 5 1 12 32 16 10 10 4 2 n Now, there could be no more welcome present to meteorologists, particularly to those who are charged with the duties of a forecaster. than such a siniple key to the confusion that surrounds tlie weather's changes. How much pleasanter the task of weatslier forecasting if, by a glance a t the moon's position as given in an mtrononiical ephemeris, one could ascertain the actual tendency of the weather to improve, to grow worse, per- haps even the tendency to a given pressure distribubon, instead of having painfullv to acquire a knowledge con- cerning the behavior of lows, etc., that still leaves so many possibilities open. For this very reason there actually are no small number of scientific studies of a possible lunar influence on the weather. To be sure, the instigators of the repeatedly reappearing lunar systems of weather prophecy are usu- 180 MONTHLY WEATHER REVIEW. APRIL, 1915 counts into 5-day sections, the ht new moon or full inooii of t.lie month falling in trlie niiildle of the first 5-day section and the following f i ~e cniiiing in succession there- after. This orclrr \viis adhered to in each month, t,lius eliminatiiig tlic shift of the svnoilnl iiioiitli so far AS it. was presrnt. i i i i esaiiipb will illwtrtitl. the iiictlintl : ally wholly ignorant of the fact that, when there is such a complex cooperation of many causes which can not be sifted by experiment, the truth of the matter can only be demonstrated by discussing a sufficient,ly large amount of observational material by the aid of correct statistical methods. Such peo le prophesy wildly on the staren tli of some coincidence. ?hey are usually quite lacking, afso, in the proper self-criticism; in their eyes everythiii c.onfimnis to their agreeable self-deception. Nevertheless, the application of correct methods has brought out several points wherein there wc signs of a lunar influence, aiid these must be further iiivestigat,erl. On the one hand these sips indicate an a.tniospherin tidal movement, very slight, t,o be sure, aiid of infiiiitesiniaa effect upon weather and wind, as are the daily barometric variations in any case. On the other hand t ,h y point to more or less considerable fluctuations of about one month's duration; tlie regularity of these swings leaves it an open uestion whether they belong with one of the or these have similar durations. At present we will consider only these iiiont,lily v-aria- tioiis. So far we hnve t,wo fluctuat,ions n.p mrently so analyze them es1iaust)ively-viz, (1 1 the strong prrssure variations of the synodal month f d i n g in t,he Inst month of our year, cliscovcrecl by G. Meyer and I<. Sceninnn in 1S90; and (2 ) the variation in thuaclei.storni frequcnoy also accompanying thc syiiodal nioiitli, discovered Iiy Luedicke in 1S75. The closer investmigation of these two periodicities seeina promising, bF;cause re entecl investiga- tions of long series of observations by xff erelit studeiit,s have revealed their occurrence. Seemixiin rtnd IIeyrr f ouiiil the first while working independently on the series I S69- 18S6 and 1876-1880. Afber Luedickc had fouiid t,he set:- ond case, it was again discovered (with ti. smder :tiiipli- tude, to be sure) in 1SS5 by the prrseiit writ,er' md later b Richter,' Hazen, Ifeyer, Gruss, Polis, nncl othxs,5 as d o in 1s9s by ~lilioliii nncl ,Arrhonius.G I jinvc soug~it. to iiivesti ate thesc two prohleiiis its cslinust,ivr.l;y ns pos- sible, ut' d iziiig all the published ohservil.tio1ls. Aft.vr lnyiiig aside the consideration of the first prohlcni, 115 years ago,' because of the in t,ern:i.l con tr:dit:t,ions in t h n i-esdts, the work has rtgniii ndvanccd so far during thr past months that i t scenis suited for at, lmst a prrlinimn.ry notice. Seeinann and Meyer had shown t.ha t diiriii:: t.Iic1 F(?ii.ls they investigated, die pressure over central KtIrope in t,Iw niont,lis September to Janutwy st,ood, on the a.ver:igr, almost, 10 nini. (!) lomer in t,he first, diiys followinv full mooii than it did in t,lie first, days after new ninon. I t , r ~- niained to determine bobh t,he nroal est.eiit of t.liis phe- nonieiion (it could not possibly embrace t,he whole eart,h 1 and its behavior during o t,lier periods, for Seeiiiaiiii had found t,hat it did not appear on tho :xYerage during lS44-- their assumptions, and they willingly suiwnder t, K irmselves eriods of t B e lunar revolution or of the sun's rottitmion, P well supported by obsorvatioiis that it, is ( I esirti.ble to -_ 1875. In order t,o contend. wit.11 the treiiieiidous n.mouiit, of inaterial on hand, it, was necessary t.0 einploy the very simplest, methods. Consequently 110 nionns yere com- puted. but I siniply count.ecl t,he mscs of positive and negative pressure, depnrturcs from cert.nin tliresholds (Schwelleni . Since 1S76, and often earlier, t,he published meteorological records group the dnily d u e s inbo 5-day periods; it wa.s t.lierefore most, convenient to group t,he * Meteorologische Zeitschrift. November, 1S90.7 : 427. *Ztschr.d Oesterr. Ges.f. Met \Vim S tember 1575 10:31. 4 YeteorolGgische Zeitschrilt, Jahuary,'l&%, 2 :343'7; 30:-310. 5 9ee Namen- und Gachregister ojrbc Meteorologirche Zeitschrift. e Handlingar Svenska vetensk. ak. 81. No. 2. 7 A brief codtnun!cation on est ely confirnicd Meyc'r iintl Seemann's results and gave slinrpcr limits for t,lirni. In the 30-yenr niem therc regularly n ,penis n standing pressiire wive (luring tliese days txft.er new iiioon, while its t.rough lies over Scmdi- iiavia nncl the North Ycii a few days after "newmoon" [full nioon?. I n Norway t.liis rille is SO strong1.y iiiarlied that t,he di ereiice (a ) - (6 at Bodo during these 80 years was almost alwtxys positive, a.s is shown by t.he following set of numbers : three iiiont. 1 IS. 1t.s crest appc:i.rs over Scnnclinnvin t i few TABLE 2.--D[fcrtwcr (a) -(b ) t i l Bodii, ivoriony. 1875, a, 1SS0, x, lSS.j, 7, lS90, 34, 1877, 13, lSYS, 61, 1SS7, G, IS93, 1, 1S7S. -5, 1SS3, 21, lSSB, 27, 1333, 14, lSX, 46, 18S1. 13, 1SS6, 14. 1s91, 1, 1S79, 19, 18S4, 1, 1S89, 15, 1S9.4, -12. Tho amplitude of this v:wiii.t.ion clecrcases in all direc, t.ions from Norw-a.~: : in southorn Euro e (Sam Fernando- Lesina') , in t.he TTral and in Wt>st, Ckeen f and the difference is almost. zcro, while in 8ihwi:i it has tlie opposit,o sign sig- iiifyiiig t.1iti.t on t.lic nrc~:ige thr pr~ssurc after full moon wtis t,lierc. Iiiglior t.litin after new moon. It, is t,o be expected t,hst such n cniii],eiis:~.t,ioii oiwrs somewhere, and it. is 8 cause for regret that owing to the luck of pLl1Jlished daily meteorolopird obserni tioils €rom, Ani ~~i (~i ~. this phenome- non ca.11 lint he t.l.:i.cccl fart.lier. AS one rarely oniploys more t,liiin 20 g c ~s of records in H U C ~~ an investiga,t,ioii i t might, y>peiir t.1iii.t the above has estaablislirtl iin inboresting pcri!-&itj-. X cnmputation of the wrors \vnulcl giw ti. sniaI1 prob:iJ~lc error for t.hc results. Kevert,heless the periods hvforc 1S76 nrc wnntmb?g, as already st>:i,teil. The cluest.ioii now a r k s : Docs t,liis ap- j,ea.raiice and disappear:i.nci? form pnrt of it longer perio- dicitv 2 If t.liis is t,lio case, t,he result. is a vnluable one which iiiigltt bo iisecl to ii cc,rt,:iin de reo in practical then wc fii.cc? :i. strange n.rcident, from which no c;onclu- sions can 1>c drn.wn for t.he futuro. In resuming t,lio iiivest,igtitioii of this clucst,ion, I trliere- foro set myself the t,nsk of t.rnc.ing this qu&ionttble rela.- tion through as ni.zlly ye!nrs ns possible, und cnlled on Dr. Burohard nntl Capt. Bar:hninnn of the Deut,sclw Seewttrte to assist me. I had already bcert struck by tlie fact that the magnitude of the vnrintion, after being somewhat sniootlied, seeniecl to point to a 6-yew fluctuation. The recent beautiful results of thc 1 1-year t,eni ~crature period and Peterson's suppositions regarding t ll e relation be- tween sun-spot period nad moon encouraged me to \i-c?:Lt.lier forcctists. If the longer perioi f icity is wanting, - ._ . . 8 Annnlen (1. IIydr. 11. mar. Metcmol., 1314: 214. PRIL, 1915. MONTHLY WEgTHER REVTEW. 181 . - -- . .- ....... _- .... _- .... .- 1-7 I;m .......... -2.7 1 x 1 . ......... -45 i;.w1.._. .I. ... 4 17911 .......... !I ............... ison .......... 52 iiiin ..__._. ._. I- .>