Normal-incidence solar radiation values were measured during the IGY at the South Pole and Little America (Antarctica), at Mauna Loa (Hawaii), Tucson (Arizona), and Blue Hill Observatory (Massachusetts); some results are given in tables and graphs. Essential differences among them are discussed. The radiation data at Tucson and Blue Hill are appreciably lower than at the other stations. The radiation, corrected for solar distance, is similar at the Antarctic stations to the radiation measured at Mauna Loa. However, the actual measured values in summer are higher at the South Pole than at Mauna Loa, because the sun is closer to the earth in the Southern Hemisphere summer. The “extrapolated turbidity factor” is over 2.5 at Tucson and Blue Hill, but averages 2.0 or less at the other stations with the lowest values of about 1.5 at the South Pole.




Paper delivered by S. Fritz to International Radiation Commission of IUGG, 1959, Oxford, England.