Preliminary spectroradiometric measurements of the solar constant

Abstract

Spectl'oradiometric measurements of the distribution of direc t solar radiation at Sunspot, New Mexico (altitude 9,200 feet). in June 1955 are d escribed. Detailed spcctral data were obtained within the spectral range of 299 to 535 millimicrons for different air masses. At longer wavelengths radiant-energy evaluations ,rere made only for selectcd points between the water-absorption bands.From these data, supplemented by other measurements and estimates for radiantenergy intensities for very s hort and very long wavelengths, a preliminary spectral integrat ion of the total solar intensity yields a solar constant in general agreement wiLh the best published values.

Some studies of atmospheric transmittance on mauna loa

“…These data were evaluated in a manner similar to that previously followed and were found to be in general agreement with the earlier data [3] both as to spectral quality and absolute magnitude, except that they show a higher degree of scattering as a result of difficulti es in keeping the power supply constant, or as the result of changes in atmospheric humidity.…”

“…This value is in cIo e agreement with the r esults of previous measurements of high altitude ozone at Climax, Colo. [1], and at Sunspot, N. Mex. [2,3]. In figure 4 the same experim ental data (for wavelengths shorter than about 337 m}.!)…”

“…Following the same procedures as employed in previous work [1][2][3] the atmospheric transmission curve for the atmosphere above Mauna Loa (see figs. 3 and 4) was determined on the basis of two sets of ozone transmission coefficients-those of Fabry and Buisson [6], and those of Vigroux [7]for the average data for 4 days in May (May 21, 28, 29 , and 30).…”

“…During t he pas t few years m easurem ents on the sp ectral distribution of t he r adiant energy from the sun have been carried out at locations in Colorado and N ew' M exico [1][2][3]1 b ecause of high al ti tude and gr eat distance from commercial activities. How--ever , in each case t h er e wa a considerable amount of interIer en ce r esultin g from t he presen ce of r elatively gr ea t amounts of dust or water vapor much of t he time.…”

Solar flux and its variations

“…c Sum of the irradiance occurring at this wavelength interval and at shorter wavelengths as a percent of the total irradiance. Aldrich and Hoover, 1952Stair and Johnston, 1954Johnson, 1954Allen, 1958Cast, 1965Stair and Ellis, 1968Labs and Neckel, 1968Makarova and Kharitonov, 1969High-altitude measurements: Thekaekara, 1970 higher for X-rays and for the far UV. The coincidence of H a flares with short wavelength radiation enhancements is by no means one to one.…”