SOLAR RADIATION AND ATMOSPHERE — STETSON 169 



Attempts to correlate weather changes with solar phenomena have 

 thus far met with varying success. In spite of many conflicting re- 

 sults, it appears that in general the temperature of the world at large 

 is somewhat higher at sunspot minima than at sunspot maxima. This 

 seems at first paradoxical, since we might well expect that at sunspot 

 maxima the sun would send us more heat and radiation than at sun- 

 spot minima. Many of Dr. Abbot's observations, especially during 

 the earlier years, seem to corroborate this. Yet the surface tempera- 

 ture of the globe could be actually cooler in years when the earth is 

 receiving more heat from the sun, for increased heat produces in- 

 creased evaporation which in turn generally results in increased rain- 

 fall. Increased rainfall actually lowers the temperature of the earth's 

 surface and again, by evaporation, continues to cool the air imme- 

 diately above. Furthermore, with the warming of the earth, a vast 

 convectional system of atmospheric currents results. As air warmed 

 near the surface of the earth rises, cold air flows in from the polar 

 regions with its chilling effects. It appears entirely possible that 

 even with an increase in the heat received by the earth from the sun, 

 as far as surface conditions are concerned, actually lower tempera- 

 tures would occur at selected regions. 



As far as changes in the sun's radiation affecting the general circu- 

 lation of the atmosphere are concerned, it is to be expected that such 

 changes would ultimately give rise to the formation of storms and the 

 storm tracks resulting. One of the difficulties in establishing any in- 

 timate connection between weather and sunspots is that our observa- 

 tions of weather tend to be very local. 



If progress is to be made, it will come through a consciousness of the 

 distribution of weather as a whole over the entire globe. From a 

 more accurate picture of world weather, indications for weather in a 

 given locality at a given time may be more easily estimated. 



Looking at the weather on a world-wide scale, Henry Helm Clay- 

 ton, of Canton, Mass., has found that pressures oscillate from one 

 region to another in some way which appears to depend upon the in- 

 tensity of solar activity. He finds there is an opposite trend over the 

 continents and oceans in summer as compared with winter, and that 

 the trend is different in tlie equatorial regions from that in the extra- 

 tropical belts. In the equatorial regions temperatures are distinctly 

 lower at sunspot maximum and higher at sunspot minimum. The 

 same is true in the North and South Temperate Zones, but in the 

 arid regions bordering the Tropics, the temperature actually aver- 

 ages a little higher around sunspot maximum than at sunspot mini- 

 mum. From his studies he concludes that while the North Atlantic 

 shows 10 to 20 percent more precipitation, the eastern half of the 

 United States is in the region where rainfall is actually less during 

 maximum activity on the sun. He concludes that our weather is the 



