Balloon-borne disposable radiometer for cloud detection

Harrison, G. ORCID: https://orcid.org/0000-0003-0693-347X and Nicoll, K. ORCID: https://orcid.org/0000-0001-5580-6325 (2012) Balloon-borne disposable radiometer for cloud detection. Review of Scientific Instruments, 83 (2). 025111. ISSN 0034-6748 doi: 10.1063/1.3685252

Abstract/Summary

A low cost, disposable instrument for measuring solar radiation during meteorological balloon flights through cloud layers is described. Using a photodiode detector and low thermal drift signal conditioning circuitry, the device showed less than 1% drift for temperatures varied from +20 °C to −35 °C. The angular response to radiation, which declined less rapidly than the cosine of the angle between the incident radiation and normal incidence, is used for cloud detection exploiting the motion of the platform. Oriented upwards, the natural motion imposed by the balloon allows cloud and clear air to be distinguished by the absence of radiation variability within cloud, where the diffuse radiation present is isotropic. The optical method employed by the solar radiation instrument has also been demonstrated to provide higher resolution measurements of cloud boundaries than relative humidity measurements alone.