Earth and Sun: an Hypothesis of Weather and Sunspots

Abstract

FOR half a century or more, it has been known that the earth's magnetic condition variesjin striking similarity with the state of activity on the sun's surface. Many attempts have been made to establish similar connexions between meteorological phenomena and the sunspot cycle, but only within recent years has it been possible to record indisputable success in such attempts. The element most clearly affected is, as might have been expected, the temperature. Koppen's work, supported by that of -several other writers, demonstrates that at sun-spot maximum the mean temperature of the atmosphere is' slightly less than at sunspot minimum. The difference is small, being o°-6 C. in the tropics, and falling to o°-4 C. in temperate latitudes. It seems not unlikely that the diminution at sun-spot maximum corresponds rather to increased terrestrial absorption-due to a greater amount of ozone in the upper atmosphere--than to diminished output of radiation from the sun. The sun sends out increased corpuscular emission, and almost certainly increased ultraviolet radiation, at times of sunspot maximum, so that it would be rather surprising were its total radiation to be diminished at such times. On the other hand, intensified short-wave radiation would probably produce more ozone, which would intercept a larger proportion of radiation on its way to the earth's surface.

Earth and Sun: an Hypothesis of Weather and Sunspots.

By Ellsworth Huntington. With a Chapter by H. Helm Clayton. Pp. xxv + 296. (New Haven: Yale University Press; London: Oxford University Press, 1923.) 23s. net.