BLACK-BALL OBSERVATIONS AND THE RADIATION CHART

Abstract

This paper presents comparisons of experimentally determined radiation temperatures using the black ball, with such temperatures calculated using the Elsasser radiation chart. The comparisons show that, in general, the calculated temperatures are always warmer than those observed, indicating that the earth and its atmosphere radiate less energy away to space than would be calculated. The agreement between observation and calculation appears to be best in summer, when the water-vapor path length is greater at all altitudes, and worst in winter. A description of the approximations which enter into the calculations and a detailed investigation of the validity of these assumptions, obtained by noting experimental results, are also presented. The conclusions are that some of the approximations are experimentally verified only in part and that two of them, the separation of CO2, ozone, and water vapor radiative effects, and the use of a pressure scaling factor on path lengths, are clearly invalidated.