Solar and Infrared Radiation Measurements

12 Solar Spectral Measurements

I shall without further ceremony acquaint you that in the year 1666, I procured me a triangular glass prism, to try therewith the celebrated phenomena of colors.

Sir Isaac Newton

(1642–1727)

12.1 Introduction

Solar radiation is not uniformly distributed in wavelength. The spectral distribution of solar radiation as it arrives at the top of the atmosphere is equivalent to a blackbody spectrum with an effective temperature of 5777 K that is modified by selective absorption and emissions in the sun’s own atmosphere. This radiation is further and significantly modified by scattering and absorption processes as it passes through the earth’s atmosphere before it reaches the surface.

This chapter begins with a discussion ...