Resolving the size of ice-nucleating particles with a balloon deployable aerosol sampler: the SHARK
Resolving the size of ice-nucleating particles with a balloon deployable aerosol sampler: the SHARK
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DOI：
10.5194/amt-13-2905-2020
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发表时间：
2020-06-03
影响因子：
3.8
通讯作者：
Murray, Benjamin J.
中科院分区：
文献类型：
--
作者：
Porter, Grace C. E.;Sikora, Sebastien N. F.;Murray, Benjamin J.
冰核粒子（INPs）影响云的发展、寿命和辐射特性，因此了解整个大气中INPs的丰度非常重要。决定INPs的寿命和迁移的一个关键因素是它们的大小;然而，几乎没有大小分辨的大气INPs浓度信息存在。在这里，我们提出了一个无线电控制的有效载荷能够收集尺寸分辨气溶胶从系留气球离线INP分析的主要目的的发展和应用。这一有效载荷被称为SHARK（选择高度气溶胶研究工具包），由两个互补的级联撞击器组成，用于分离0.25至10微米的气溶胶粒度，带有一个后过滤器和顶部级，用于收集低于和高于这一范围的颗粒，流速高达100升/分（-1）。SHARK还包括一个光学粒子计数器，用于量化0.38至10 μ m之间的气溶胶粒度分布，以及一个无线电探空仪，用于测量温度、压力、全球定位系统高度和相对湿度。这一切都被安置在一个防风雨的盒子里，可以用电池运行长达11小时，总重量为9公斤。无线电控制和与无线电探空仪的实时数据链路使用户能够根据气象条件和高度开始和停止采样，例如，这可以使用户避免在非常潮湿或多云的空气中采样，即使鲨鱼不在视线范围内。虽然收集的气溶胶，原则上，可以与一系列的分析技术进行研究，本研究表明，收集的气溶胶可以分析与离线液滴冷冻仪器，以确定大小分辨INP浓度，活化分数，和活性部位密度，产生类似的结果，使用标准的PM10气溶胶采样器时，总结了适当的大小范围。测试数据，鲨鱼是采样近地面水平或悬挂在20米高度的系留气球，从四个对比鲜明的位置有非常不同的尺寸分辨INP光谱：Hyytiala（芬兰南部），利兹（北方英格兰），朗伊尔城（斯瓦尔巴群岛），和卡丁顿（英格兰南部）。
Ice-nucleating particles (INPs) affect cloud development, lifetime, and radiative properties, hence it is important to know the abundance of INPs throughout the atmosphere. A critical factor in determining the lifetime and transport of INPs is their size; however very little size-resolved atmospheric INP concentration information exists. Here we present the development and application of a radio-controlled payload capable of collecting size-resolved aerosol from a tethered balloon for the primary purpose of offline INP analysis. This payload, known as the SHARK (Selective Height Aerosol Research Kit), consists of two complementary cascade impactors for aerosol size-segregation from 0.25 to 10 mu m, with an after-filter and top stage to collect particles below and above this range at flow rates of up to 100 L min(-1). The SHARK also contains an optical particle counter to quantify aerosol size distribution between 0.38 and 10 mu m, and a radiosonde for the measurement of temperature, pressure, GPS altitude, and relative humidity. This is all housed within a weatherproof box, can be run from batteries for up to 11 h, and has a total weight of 9 kg. The radio control and live data link with the radiosonde allow the user to start and stop sampling depending on meteorological conditions and height, which can, for example, allow the user to avoid sampling in very humid or cloudy air, even when the SHARK is out of sight. While the collected aerosol could, in principle, be studied with an array of analytical techniques, this study demonstrates that the collected aerosol can be analysed with an offline droplet freezing instrument to determine size-resolved INP concentrations, activated fractions, and active site densities, producing similar results to those obtained using a standard PM10 aerosol sampler when summed over the appropriate size range. Test data, where the SHARK was sampling near ground level or suspended from a tethered balloon at 20m altitude, are presented from four contrasting locations having very different size-resolved INP spectra: Hyytiala (southern Finland), Leeds (northern England), Longyearbyen (Svalbard), and Cardington (southern England).