Longwave radiation at the ground: IV. Comparison of measurement and calculation of radiation from cloudless skies

✍ Scribed by G. J. Dalrymple; M. H. Unsworth

• Publisher: John Wiley and Sons
• Year: 1978
• Tongue: English
• Weight: 618 KB
• Volume: 104
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710444211

✦ Synopsis

Abstract

On cloudless days in summer, longwave irradiance was measured with a radiometer and was calculated from a radiation chart using records from radiosondes released at regular intervals. The results show that the chart underestimated the longwave flux density at the ground by up to 40 Wm^−2^, corresponding to an extra atmospheric emissivity of up to 0.12. The extra emissivity was correlated with turbidity during the day, and on turbid days it showed a diurnal variation with a maximum at noon. It is suggested that emission in the atmospheric window from dust, pollen and spores may account for some of the observed excess.