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.
Acknowledgements
We thank Leif Bäcklin for his invaluable help in the construction of the instrument. We thank all helpers in the field, particularly Luisa Ickes and Karolina Siegel, for their invaluable assistance and help. Linn Karlsson (ACES) is thanked for providing the data acquisition software. We gratefully acknowledge Emmy Nilsson (MISU) for invaluable assistance with the ion chromatography analysis. We would like to extend our acknowledgement to Peggy Achtert for providing the ceilometer data and the Atmospheric Measurement Facility of the British National Centre for Atmospheric Science for providing the ceilometer. The Swedish Polar Research (SPRS) provided access to the icebreaker Oden and logistical support. We are grateful to the SPRS logistical staff and to Oden’s Captain Mattias Peterson and his crew.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
This work was supported by the Swedish Research Council (grant no. 2016-03518, 2018-04255 and 2016-05100), the Swedish Research Council for Sustainable Development FORMAS (grant no. 2017-00567), the Knut-and-Alice Wallenberg Foundation (ACAS project, grant no. 2016.0024), the UK Natural Environment Research council (grant no. NE/R009686/1), the Bolin Centre for Climate Research at Stockholm University, as well as the European Research Council (ERC, MarineIce: grant no. 648661).
Data availability
The data of this study is available on the Bolin Centre for Climate Research Database:
Julika Zinke, Emmy Nilsson, Luisa Ickes, Matthew Salter, Caroline Leck, Michael J. Lawler, Grace Porter, Michael Adams, Ian Brooks, Ben Murray, Paul Zieger (2021). Cloud water samples obtained in summertime during the Arctic Ocean 2018 expedition. Dataset version 1.0. Bolin Centre Database. https://doi.org/10.17043/ao2018-cloud-water
Supplemental data
Supplemental data for this article can be accessed here.