Data for ‘Resolving the size of ice-nucleating particles with a balloon deployable aerosol sampler: the SHARK’

• Main Authors: Porter, Grace C. E., Sikora, Sebastien N. F., Adams, Michael P., Proske, Ulrike, Harrison, Alexander D., Tarn, Mark D., Brooks, Ian M., Murray, Benjamin J
• Format: Dataset
• Language: English
• Published: University of Leeds 2020
• Subjects: F331 - Atmospheric physics; Longyearbyen; Svalbard
• Online Access: http://archive.researchdata.leeds.ac.uk/671/; http://archive.researchdata.leeds.ac.uk/671/1/Datasets_for_SHARK_Figures.zip; http://archive.researchdata.leeds.ac.uk/671/2/Datasets_for_SHARK_Figures.zip.manifest.txt

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. This is especially so in the free troposphere. 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 µm, with an after-filter and top stage to collect particles below and above this range at flow rates up to 100 L min-1. The SHARK also contains an optical particle counter to quantify aerosol size distribution between 0.38 and 10 µm, 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 off-line 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 is presented from four contrasting locations having very different size resolved INP spectra: Hyytiälä (Southern Finland), Leeds (Northern England), Longyearbyen (Svalbard), and Cardington (Southern England).