Identifier: smithsonianmisce821931sm (find matches)
Title: Smithsonian miscellaneous collections
Year: 1862 (1860s)
Authors: Smithsonian Institution
Subjects: Science
Publisher: Washington : Smithsonian Institution
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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here the maxima and minima of the waves occur successively laterat Stykkisholm, Rome, and Calcutta, the minima and maxima atCalcutta being about 7 years later than at Stykkisholm. These facts render it evident that the rate of latitude displace-ment is a general law for periodic oscillations of all lengths. Thislaw may be stated as follows : Law of latitude displacement of periodic zuaves.—Periodic oscil-lations in atmospheric conditions progress in latitude from point topoint along a meridian at a rate that would carry the wave frompole to Equator in one period, whatever the period of oscillation. It is probable that the law of displacement in longitude is equallysimple. Figure 14 shows that the 7-day wave progressed in longi-tude alx)ut 180°, or half around the world, in seven days. Die 3-3^ jahrige und die 2 jiihrige Temperaturschwankung, von ErnstRietschel. Geographical Institute of the University of Leipzig, Vol. IV, No. 1,1929. 26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82
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NO. 7 THE ATMOSPHERE AND THE SUN CLAYTON 2/ A proportional rate of progress appears to occur in the periodicwave of about 7.5 years. Figure 17 shows the centers of oscillation ina 7.5-year wave on a world map. This map is derived from har-monic values computed from groups of three periods between 1883and 1913 at 117 stations scattered over the world. It shows thecenters of oscillations at the epochs, 1885, 1893, 1900, etc. Con-tinuous lines show equal values above normal and broken lines showequal values below normal. It is not possible with available datato follow the progressive movement of all the centers, but the centerover Greenland shows a distinct progress from west to east. Thisprogress will be evident from figure 18 which shows the centers ofoscillation in the area between 50° W. and 120° E. north of the Equa-tor when the epochs are taken successively two years later. Theresults in figure 18 are derived from the data of 48 stations takenfrom World Weather Records. In 1885 t

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