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.

摘要

云水的化学成分可用于推断在其上形成云滴和冰晶的颗粒的来源。为了获得用于分析原始高北极地区高架云化学成分的云水，气球式主动云水采样系统是最佳方法。然而，由于其重量和挑战性的环境条件，这种系统先前无法部署。我们利用电池技术的最新发展来开发一种小型的云水采样器，用于气球式收集云水。我们的采样器是散装采样器，其云滴截留直径约为8 µm，估计收集效率为70％。采样器被加热以防止过多的冰积聚，并且能够在北极高海拔地区遇到的极端条件下运行几个小时。2018年8月和2018年9月，在北极附近，在高北极地区的微生物-海洋-云耦合（MOCCHA）活动中，我们已将新采样器测试并部署在系留气球上。采样器能够成功检索经过分析的云水样品，以确定其化学成分及其冰核活性。考虑到北极高地的原始条件，我们非常重视开发合适的清洁程序，以最大程度地减少采样器本身对背景的污染。2018年8月和2018年9月，在北极附近，在高北极地区的微生物-海洋-云耦合（MOCCHA）活动中，我们已将新采样器测试并部署在系留气球上。采样器能够成功检索经过分析的云水样品，以确定其化学成分及其冰核活性。考虑到北极高地的原始条件，我们非常重视开发合适的清洁程序，以最大程度地减少采样器本身对背景的污染。2018年8月和2018年9月，在北极附近，在高北极地区的微生物-海洋-云耦合（MOCCHA）活动中，我们已将新采样器测试并部署在系留气球上。采样器能够成功检索经过分析的云水样品，以确定其化学成分及其冰核活性。考虑到北极高地的原始条件，我们非常重视开发合适的清洁程序，以最大程度地减少采样器本身对背景的污染。采样器能够成功检索经过分析的云水样品，以确定其化学成分及其冰核活性。考虑到北极高地的原始条件，我们非常重视开发合适的清洁程序，以最大程度地减少采样器本身对背景的污染。采样器能够成功检索经过分析的云水样品，以确定其化学成分及其冰核活性。考虑到北极高地的原始条件，我们非常重视开发合适的清洁程序，以最大程度地减少采样器本身对背景的污染。