Abstract
The chemical composition of cloud water can be used to infer the sources of particles upon which cloud droplets and ice crystals have formed. In order to obtain cloud water for analysis of chemical composition for elevated clouds in the pristine high Arctic, balloon-borne active cloud water sampling systems are the optimal approach. However, such systems have not been feasible to deploy previously due to their weight and the challenging environmental conditions. We have taken advantage of recent developments in battery technology to develop a miniaturised cloud water sampler for balloon-borne collection of cloud water. Our sampler is a bulk sampler with a cloud drop cutoff diameter of approximately 8 µm and an estimated collection efficiency of 70%. The sampler was heated to prevent excessive ice accumulation and was able to operate for several hours under the extreme conditions encountered in the high Arctic. We have tested and deployed the new sampler on a tethered balloon during the Microbiology-Ocean-Cloud-Coupling in the High Arctic (MOCCHA) campaign in August and September 2018 close to the North pole. The sampler was able to successfully retrieve cloud water samples that were analysed to determine their chemical composition as well as their ice-nucleating activity. Given the pristine conditions found in the high Arctic we have placed significant emphasis on the development of a suitable cleaning procedure to minimise background contamination by the sampler itself.
Highlights
The collection of fog or cloud water with a subsequent collector (CASCC) developed by Daube et al (1987) has analysis of chemical composition is an essential tool to become one of the preferred sampling instruments in better understand the role of aerosol in the formation many studies and has been further developed into sizeand removal by cloud droplets or ice crystals
A variety fractioning collectors (e.g. Monger et al, 1989; Collett of cloud water collectors have been developed in the et al, 1995), smaller versions such as the CASCC2 recent decades, including passive, active, single-stage and (Demoz et al, 1996) or the mini-CASCC developed by size-resolved collectors
The lower collection efficiency of the mini-CWS compared to the CASCC2 and Caltech Heated Rod Cloudwater Collector (CHRCC) could be explained by the smaller size and the lower flow velocity in the mini-CWS
Summary
The collection of fog or cloud water with a subsequent collector (CASCC) developed by Daube et al (1987) has analysis of chemical composition is an essential tool to become one of the preferred sampling instruments in better understand the role of aerosol in the formation many studies and has been further developed into sizeand removal by cloud droplets or ice crystals. Among Collett et al, 1990) is a further developed version of the CASCC2 where the Teflon strings have been replaced by heatable stainless steel rods. 11 Â 11 cm 3.175 mm ÃThe weight of the mini-CWS is given for the whole sampling kit including batteries and sensors, while the weights of the CASCC2 and CHRCC comprise only the samplers. Droplets are actively accelerated towards a sampling volume by a fan, where they impact on Teflon strings (or stainless steel rods for the CHRCC) and are collected in a sampling bottle situated below the cassette
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
