Notes on the measurement and estimation of atmospheric radiation –2

Abstract

AbstractAn account is given of further measurements of atmospheric radiation which confirm former conclusions regarding the errors of two types of radiation chart when used to compute total radiation at the surface. The greater part of the difference between computed and observed radiation is attributed to two causes – emission from particulate matter and the variation of emissivity of water vapour with temperature. The results suggest a form for this variation between −5°C and +25°C.Some measurements and computation of the change of radiative flux in the lowest metre at night, i.e., of the direct radiative cooling of the air, are reported. Miscellaneous subjects discussed include the radiation from atmospheric dust, the radiative temperature of a short grass surface and its measurement by simple means in all conditions, and an anomalous occasion with very high incoming radiation for which no explanation could be found. Some comments are offered on the experimental justification of two possible uses of the radiation charts.