A self-calibrating wide range electrometer for in-cloud measurements

Harrison, G. ORCID: https://orcid.org/0000-0003-0693-347X, Nicoll, K. ORCID: https://orcid.org/0000-0001-5580-6325, Marlton, G., Williams, P. ORCID: https://orcid.org/0000-0002-9713-9820 and Airey, M. ORCID: https://orcid.org/0000-0002-9784-0043 (2017) A self-calibrating wide range electrometer for in-cloud measurements. Review of Scientific Instruments, 88 (12). 126109. ISSN 0034-6748 doi: 10.1063/1.5011177

Abstract/Summary

Charge is observed in clouds of all forms, which influences their development and properties. In-cloud charge measurements require a wide dynamic range instrument, extending from charge in aerosols and dusts to that present in thunderstorms. Unexpectedly large charge densities (>200 pCm-3) have recently been detected in layer clouds using balloon-carried linear electrometers. These, however, lead to instrument saturation if sufficient sensitivity for aerosol and droplet charge is maintained. Logarithmic electrometers provide an alternative, but suffer strong non-linear thermal effects. This is a limitation for balloon-carried instruments which encounter temperature changes up to ~100 °C, as full thermal compensation requires complexity inappropriate for disposable devices. Here, a novel hybrid system is described, combining linear and logarithmic electrometers to provide extended dynamic range (±50 pA), employing the negligible (±4%) total temperature drift of the linear device to provide in situ calibration of the logarithmic device. This combination opens up new measurement opportunities for charge in clouds, dusts and aerosols.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/74379
Identification Number/DOI	10.1063/1.5011177
Refereed	No
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Institute of Physics
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