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Show WUijCOieaid warn ma mum v&uenwdi iter lord Cab ' J I -EARTH Q I SUN iVfM mm. ;'- yfj EARTH Q x I 'i TW sun I 92,897,400 miles from the Hi The un revolves on its axis 7 .ntv-seven days. The earth re- iB in twenty-four hours. AH life o Sometimes one side of the sun is violently vio-lently broken out with unusual streamers stream-ers of intensely hot gases reaching hundreds of thousands of miles into space, while the other hemisphere of the sun has less sun I spots and, therefore, is cooler. j The heat at the sun's surface aver-if aver-if ages about 6,000 degrees. When the face of the sun most violently inflamed in-flamed with terrific heat is turned toward the earth we would naturally expect a heat wave. A But astronomers Jiave found out that exactly the opposite happens during the violent eruption of sun spots the earth is colder because this radiation of heat stirs up clouds which act' as a sort of sunshade for the earth's surface. C When the cooler hemisphere of the sun revolves around so that it faces the earth we get less radiated heat from the sun and it would be supposed that we would have cooler weather on our earth. Cy But, curiously enough, during the pe riod when the superheated sun spot are turned away from the earth and we have a reduced amount of radiated heat from the sun there are less clouds in our sky and therefore we have hotter weather. from High Mountain Tops in Widely Separated I Places Astronomers Have Been Studying Sun - Spots and Measuring the Variations of Heat Jntil Science Has Now Learned to Understand 3 How They Affect Our Weather The Outer Shell of Dazzling White-Fire Clouds Upon V.'hich Our Life Depends. This Diagram Also Shows the Darker Interior ef Metallic Vnnnr dnildK. iiCIEN'CE at last believes it has discovered a way to make uj j weather predictions which ultimately will have a much J 0 gher degree of accuracy than at present Careful and H' persistent observation of the radiations of heat from the sun Ntltave been made from mountain tops above the clouds and W mists and dusts of the earth in many widely separated por- ,' tions of the globe. From these records astronomers now know that the sun spots have a very immediate and important PlTn lDfiiience upon our weather. x' ' The sun revolves on its axis once in' twenty-seven days. "L5!'ta one-half of the sun is in a state of violent eruption and in- - tense heat, and another portion of the sun has much less sun-ipo't sun-ipo't activity and is, therefore, considerably cooler, it is easy to see that while the extra hot face of the sun is turned to-tard to-tard us we would, naturally, have rather different weather than when the cooler hemisphere of the sun has revolved, around so that it faces the earth. In a general way it may be said that the hopes of perfecting perfect-ing our weather predictions to a much higher degree of accuracy ac-curacy rest upon the watchful eye of the astronomers In the mountain top observatories scattered about the globe. Already Al-ready several such observatories have been established, hut it is important to complete the chain with more stations. It would seem at first glance very easy for an astronomer to note an outburs of special sun-spot activity, and that even' a high-school pupil could then write a weather prediction of "fair and warmer." But the whole matter is a very complicated compli-cated one. It is a curious fact, for instance, that when the sun is radiating its maximum of intense heat we have a spell of cool weather! V ,.riTO.a,.I,i:...r.allitiyw,, ; An &&T - U x - i $ s where rainfall is practically prac-tically unknown. Here daily measurements of the solar radiation are being obtained as far as possible. The results at this station are 'toeing 'toe-ing confirmed by simul-'taneous simul-'taneous observations at the stations of the As-trophysical As-trophysical Observatory on Mount Wilson, Cal., at an elevation of five thousand seven hundred hun-dred feet, where determinations deter-minations of the solar constant of radiation have been made almost continuously since 1905. Simultaneous observations obser-vations of the solar constant of radiatiori were also made in the years 1911 and 1912 at Mount Wilson and at Bassour, in Algeria, at an elevation of three thousand six hundred feet. The fact that the D T l- 1 Hf T o,.,;. (The Writer of This Article Is Connected with the Nautical t5y lSaDd iVl. i-eWlS, Almanac Office of the United States Naval Observatory.) 0 explain with scientific accuracy the facts which scientists now are ' studying with a view to greater ft ictical benefit for mankind in weather easts, it Is necessary to understand it the sun is a variable star; that its; 1 1 liations fluctuate periodically with a ' ge of nearly 10 per cent between ex-' ex-' sues. And thus there follows a chain consequences of great importance to - iw In the form of changes of atmospheric Editions of temperature, pressure, cloudi- ""s and, possibly also, winds and rain fall, as is indicated by the researches of the Astrophysical Observatory of the Smithsonian Institution. These observers have been inquning into the variations in the solar constant of radiation, and have carried on their work for the past fourteen . years under the directorship of Dr. C. G. Abbot, and similar investigations have also been made by Dr. H. H. Clayton, formerly of Blue Hills Observatory, Mass., and now of Argentina, into the effect of these variations varia-tions in the solar intensity of radiation on weather conditions. So firmly convinced is Dr. Clayton of. the relation existing between changes in the intensity of the sun's radiation and the weather that he has persuaded the Argentine Government to receive daily telegraphic reports of the change in the value of the solar constant of radiation from the station at Calama, Chili, established estab-lished by the Smithsonian Institution in 1918. The station at Calama is situated about one hundred and fifty miles northeast north-east of Antofagasta, at an elevation of .seven thousand five hundred feet, and was chosen for the reason that it is in one of the most cloudless regions of the world. Incandescent Jets from the Sun's Circle Which Shoot 100,000 Miles Out Into Space. t v - f i sY " r , 1 I K " - ) e L " h f 1 F T ft - V - v r A y 4 v ' 1 ML " i ). f A Solaf Kcmiaphcre with a Minimum of Sun Spots. A Solar Hemisphere Violently Erupted with Sun Spots. Zt Our very life is dependent umr. t ? C GLOWING FIRE-CLOUDS AM;S3 a ' - t j "V - , jf . . f, Vj i I - 1- , - ' " ' ' S y oio-: ; " ' ' - 1 results obtained at these three stations separated by a distance of several thousand thou-sand miles were the same, when nearly simultaneous observations were made and showed from day to day the same variations varia-tions of the solar constant, is proof that the variations are true solar variations and do not owe their origin to varying local conditions within our own atmosphere. There is, according to Dr. Abbot, a twofold two-fold variation in the solar radiation. There is, first, a variation of long period with a range of from 3 to 5 per cent during t'ie sun-spot cycle, and. secondly, a short, irregular ir-regular variation that runs its course in intervals of a few days, weeks or months, with a range that is usually between 3 and 7 per cent, and occasionally becomes as high as 10 per cent.. The first variation is believed to be a direct result, and the sec-'ond sec-'ond variation an indirect result, of the periodic increase and decrease of solar activity during the sun-spot cycle. As the sun-spot cycle itself is irregular and complex, com-plex, it is to be expected that the resulting result-ing changes in terrestrial weather conditions condi-tions would alpo be of a complex nature. It is well known how necessarily doubtful doubt-ful are weather predictions, depending as they do upon many different local conditions, condi-tions, such as direction of prevailing winds, position relative to large bodies of water, elevation above sea-level and many other factors. The effect of all these local conditions may mask to a great extent the effect of changes in the intensity of the solar radiation, which are also irregular and complex, depending, as they do, upon many changes of an irregular and complex nature within the sun itself. As is well known, the sun rotates on its axis in an approximate period of twenty-seven twenty-seven days, though equatorial regions of the sun rotate 'more rapidiy than polar regions. The difference in the periods of rotation of sun-spots sometimes amounts to a number of days, depending upon their solar latitude. If there is, temporarily, a hot and cold hemisphere of the sun. it will show Its effect in terrestrial weather changes that have a period equal to that of the sun's rotation on its axis, or twenty-seven twenty-seven days. Two weeks of increased intensity of radiation will be followed by two weeks of decrease Intensity of radiation, as the hot and cold hemispheres of the sun ara alternately turned toward the earth. In the year 1915 there was just such a strongly marked variation in the solar radiations, which continued for several solar rotations, but finally diminished and disappeared. To show the irregularity and complexity of the solar changes, the variations varia-tions in solar radiations for 1916 were radically different from those for 1915. The twenty-seven day pe-iods of the ypar before were no longer present. A strongly marked periodici'y of three and one-half clays appeared instead. The years 1915 and -1916 wye nar the sun-snot maximum rertod. The vrt'ion in the solar radiation has no rinfmite periodicity of short interval, then, that persists from year to year. Each year is a law unto itsf-lf, yet with well-marked predictable effects upon terrestrial weather conditions in spite of the irregular pnd complex nature of the changes. Great Britain Rights Reserved, i The connection between sun-spots and terrestrial temperature has been studied by Dr. Walker, director-general of the Indian In-dian Meteorological Department, from observations ob-servations obtained at ninety-seven stations sta-tions in all parts of the world. These show that with the exception of Northwestern Africa, the west and north coast of the Eurasian continent, Bermuda. New Zealand Zea-land and a part of the Indian Ocean, the world in general has lower temperature at sun-spot maximums than at sun-spot mini-mums. mini-mums. Since solar radiation is known to he more intense at sun-spot maximums, owing to the fact that new, hot material ia brought from the sun's interior to its surface sur-face with great rapidity at this time, this result would appear at first thought paradoxical. para-doxical. It must be remembered, however, that there are secondary results of this increased intensity of radiation. The sun's atmosphere is charged at this time" with denser gases. Caseous material is thrown . to great solar altitudes. The corona Is brighter and. it is believed, contains more gaseous particles than usual. It is also beiieved that electric ions are shot forth from the sun at this time with unusual force, and penetrate the earth's atmosphere to a greater depth, producing increased cloudiness, and thereby lowering terrestrial temperature. The increased density of the pases in the solar atmosphere atmos-phere and corona at sun-spot maximum also tends to lower the intensity of solar radiation. There'ore the direct and indirect in-direct effects of the increased, solar activity activ-ity tend to counteract each other, and as the indirect effect predominates the pnra-doxi'll pnra-doxi'll fall in terrestrial temperatures with Increased radiation at sun-spot maximum maxi-mum results. Cojplex as all th esc changes atippar they are predictable to a great (."tent, as Dr. Clayton has shovn by his detailed investigations in-vestigations for '.bout fifty stations in- all parts of th .vorld. It has been found that the temperature effects of the Irreeular fluctuations of solar radiation arrange themselves in well-defined zones. For example, ex-ample, in the tropical zone, broadening over land and narrowing over the ocean, an increase of the solar radiation is followed fol-lowed after predictable number of days (two, three or four, as the case may be) by an increase of local temperature. This relation also exists in the Arctic and Antarctic zones and down the east coast of North America. In the great temperate zones, on the other hand, an increase in solar radiation is followed by a decrease in tcmperature Dr. Clayton has also Investigated to a certain extent the relation between , changes in solar radiation and atmospheric, pressure, and finds an indication of the same arrangement info zones, with the difference that increase of temperature after increase of solar radiation is attended attend-ed by decrease of pressure and vice versa. Jt Is suspected that since marked tempera-lure tempera-lure changes follow changes in the solar radiation, further investigation would be apt to reveal important effects of chansos in solar radiation upon winds, cloudiness and precipitation. It is the df sire of Dr. C. 0. Abbot, of the Smithsonian Institution, to establish three or four additional stations in different portions por-tions of the globe for the purpose of obtaining ob-taining simultaneous observations of the solar constant of radiation. The great enemy en-emy of solar radiation work is the presence pres-ence of clouds or haziness, and it Is necessary neces-sary to establish the?B stations in the most cloudless re-ions of the world. It is cxprjeted that results, of great importance would be obtained from the detailed Investigation In-vestigation f.f the fluctuations of solar radiation, ami the resulting effects unon the earth's atmosphere ami weather conditions, con-ditions, and it is to be hoped that the half-million dollars neeried fnr Iho establishment estab-lishment ami maintenance of these additional addi-tional stations for solar radiation determinations deter-minations will be ttrantod to the Smithsonian Smith-sonian Institution in the near future. Solar radiation re'-earch is of' the highest high-est imnortanee. not only for the results made available for the accurate prediction of the won-h'r chsnr-s following change in the solar i.-.diation. but for t),(, valuable Information obtainable from the recrfrris of the spect roboioinet er, used jn these observations, ob-servations, of the transparency of the air for li'-'ht of all colors and of invisible rays, needed by all interested in the study 'of the growth of plants and in the propagation propaga-tion of signals by means of lights ou land and sea. ; f Envelope of Fir. Cloud. Which Surround the Sun and DiaSrara Showing Glimpses of the Darker Interior Vapors. Copyright, 1019, by Star Company. . i |
