Abstract
SUNSPOTS AND SOLAR RADIATION.—Spectroscopic observations, the discussion of the frequency of tropical cyclones, and cyclical variations of barometric pressure, indicate that the greatest amount of heat is received from the sun by the earth during a maximum epoch of solar activity. But, on the other hand, the discussions of statistics of air temperature and solar radiation suggest that that the sun's heat is greatest when his surface is least spotted. Some new facts in connection with this paradox are described by M. R. Savélief in the current Comptes Rendus, and seem to combat the latter result. He has made a large number of observations with a Crova's actinograph since June 1890, and compared them with the late Dr. Wolf's numbers showing the relative frequency of solar spots. A few observations are given indicating that the solar constant increases with the increase of solar activity. M. Savélief has also calculated the mean quantity of heat received on one square centimetre of horizontal surface on the ground during one day, and for an hour of solar radiation. The results obtained by this method, like those deduced from the solar constant, point to the conclusion that the calorific intensity of solar radiation increases with the activity of the phenomena visible upon the surface of the sun, that is to say, with the increase of solar spottedness. These results are diametrically opposed to those obtained by previous investigators (see NATURE, vol. xliii. p. 583), and, if they are confirmed, a real difficulty in the way of explaining the correlation of solar and meteorological phenomena will have been removed.
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Our Astronomical Column. Nature 49, 274–275 (1894). https://doi.org/10.1038/049274a0
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DOI: https://doi.org/10.1038/049274a0