H. H. Clayton Declares Recent Decline in Solar Radiation Does Not Mean Tropics Are Rapidly Cooling

"The recent statements concerning the decline in solar radiation do not form any basis for a belief that in a few years travellers in tropical regions will be obliged to wear fur coats, but they are indicative of scientific facts which bear an important relation to future forecasting of weather conditions", declared Mr. Henry Helm Clayton, prominent meteorologist, to a CRIMSON reporter in commenting upon the recent report of Dr. C. J. Abbott, of the Smithsonian Institute. Mr. Clayton has for many years cooperated with Dr. Abbott in the study of the effects upon the earth of changes in solar heat, and for the last ten years has, as the head of the Argentine Meteorological Department, used his observations in making daily weather predictions.

"Ever since systematic observation of the sun was begun about 1905," Mr. Clayton declared, "students have found that there are large variations in the heat radiated by that body, and that from one day to the next the differential may be as much as two or three percent of the total. It has also been observed, however, that the oscillations occur in a fairly regular manner, and that the phenomena of maximum or minimum heat recur in periods of about 11 years. This length of time is intimately connected with the number of 'sun spots', the radiation varying directly with the amount of solar disturbance indicated by the gaseous eruptions, or spots."

Anomalous Condition Caused

"When the radiation of heat from the sun is high," continued Mr. Clayton, "in the temperate zone the winters are colder than normal, while the summers are characterized by high temperatures. This may seem anomalous, but is easily explained. During the winter, for instance, the sun is above the tropical belt and tends to increase the warmth in that zone. Under this higher temperature the atmosphere there expands and overflows into the temperate belts, and immediately currents from the north are set in motion to restore the equilibrium in this region of diminished pressure. Consequently, during a winter of high solar radiation, the temperate zones are subject to continued and cold north winds."

"When, on the other hand, the heat from the sun is low," he went on, "conditions are much different. During the summer, when the sun is shining directly upon the temperate zones, these regions have cool weather because of the less intense heat from the sun, while the winters are mild because the districts are not subject to winds from the north. The reports of Dr. Abbott indicate that the solar radiation is low at present, and, if this condition continues, the summer will undoubtedly be cool with frequent rains and milder than usual."

"Because of the daily variations in the sun's radiation and various other factors which enter into weather forecasting," Mr. Clayton said, "this method of predictions will not be applicable for long periods in advance until scientists can determine in advance what will happen on the sun. In the Argentine, however, they are now making very accurate forecasts by this process for periods of as much as eight days, and it is safe to assume that, as this system becomes improved it will be employed generally in forecasting work all over the world."