The Solar Constant and the Solar Spectrum Measured from a Research Aircraft


Book Description

The solar constant and solar spectrum were measured from a research aircraft flying at 38,000 feet, above the highly variable and absorbing constituents of the atmosphere. A wide range of solar zenith angles was covered during six flights for over 14 hours. Eleven instruments, five for total irradiance and six for spectral irradiance, were employed. The instruments complemented each other in the measuring techniques employed and wavelength range covered, and were calibrated and operated by different experimenters. The combined results of these experiments are presented, and also a proposed standard for the solar constant and zero air mass solar spectral irradiance. The solar constant is found to equal 135.3 mW cm−2 or 1.90 cal min−1 cm−2




An Introduction To Solar Radiation


Book Description

An Introduction to Solar Radiation is an introductory text on solar radiation, with emphasis on the methods of calculation for determining the amount of solar radiation incident on a surface on the earth. Topics covered include the astronomical relationship between the sun and the earth; thermal radiation; the solar constant and its spectral distribution; and extraterrestrial solar irradiation. This book is comprised of 12 chapters and begins with an overview of the trigonometric relationships between the sun-earth line and the position of an inclined surface, followed by a discussion on the characteristics of blackbody radiation. The next chapter focuses on the solar constant and its spectral distribution, paying particular attention to extraterrestrial solar spectral irradiance and the sun's blackbody temperature. Subsequent chapters explore extraterrestrial and radiation incident on inclined planes; the optics of a cloudless-sky atmosphere; solar spectral radiation and total (broadband) radiation under cloudless skies; and solar radiation arriving at horizontal surfaces on the earth through cloudy skies. The ground albedo and its spectral and angular variation are also described, along with insolation on inclined surfaces. The last chapter is devoted to instruments for measuring solar radiation, including pyrheliometers and pyranometers. This monograph will serve as a useful guide for energy analysts, designers of thermal devices, architects and engineers, agronomists, and hydrologists as well as senior graduate students.










Solar Spectral Irradiance


Book Description