Radiometric Estimation of Cloud Cover

Abstract

Estimates of cloud cover based on all-sky temporal and spatial radiometric measurements of downward longwave radiation are compared with visual estimates of the same cloud cover. A detailed comparison of the two estimates over a five-week study period show the radiometric method to be very reliable. Examination of radiometric data taken over a period of 15 months indicates that calibration parameters required for estimating cloud cover are not seasonally dependent. Details of the analysis technique are given along with indications for future development of meteorological instrumentation.