Calibration of a Cloud Droplet Probe: A Review

Abstract

The Cloud Droplet Probe (CDP) is an in-situ open-path airborne optical particle counter which sizes and counts cloud particles based on the amount of light scattered by the particle as it passes through an incident light source. To ensure optimum quality and precision of data, calibrations are regularly performed with the CDP. The calibrations establish the relationship between scattered light and particle size, and verify the alignment of the CDP's sensitive optical components. The complex relationship between the light scattered, droplet diameter and probe geometry means instrument response to droplets of known diameter can be ambiguous. Here, uncertainties associated with the FAAM CDP calibration method are examined and two calibration methods (sizing response and sample area) are reviewed in detail. As a result, an economical, convenient and refined calibration technique, along with supporting software has been developed at FAAM, which enables the size response and sampling area of the CDP to be characterised.

Date of Award	31 Dec 2014
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Martin Gallagher (Supervisor) & Thomas Choularton (Supervisor)