Supplementary material to "Direct evidence for secondary ice formation at around −15 °C in mixed-phase clouds"

Abstract. Ice crystal numbers can exceed the numbers of ice-nucleating particles (INP) observed in mixed-phase clouds by several orders of magnitude also at temperatures that are colder than required for the Hallett-Mossop process (−3 °C to −8 °C). These observations provide circumstantial evidence of secondary ice formation. Attempting a more direct observational approach we made use of the fact that planar, branched snow crystals (e.g. dendrites) grow within a relatively narrow temperature range (about −12 °C to −17 °C) and can be analysed individually for INP using a field-suitable drop freezing assay technique. During February and March 2018, we analysed 190 dendritic crystals (an average of ∼3 mm in size and between 1.3 to 7.6 mm) deposited within mixed-phase clouds at the High Altitude Research Station Jungfraujoch (3580 m a.s.l.), Switzerland. Overall, one in eight of these crystals contained an INP active at −17 °C or warmer, while the remaining seven of eight most likely resulted from secondary ice formation within the clouds. The ice multiplication factor we observed was small (8), but relatively stable throughout the course of the experiment. These measurements show that secondary ice can be observed at temperatures around −15 °C in the atmosphere and thus advance our understanding of the extent of secondary ice formation in mixed-phase clouds, even where the multiplication factor is smaller than 10.

• Publication year

  2018

• Venue

  Atmospheric Chemistry and Physics

• Publication date

  2018-08-22

• Fields of study

  Materials Science, Physics, Environmental Science

• Identifiers
  DOI 10.5194/ACP-2018-829
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• No claims are published for this paper.

• No concepts are published for this paper.

• ImageJ for the Next Generation of Scientific Image Data

  2019cited by this paper
• HOVERCAT: a novel aerial system for evaluation of aerosol–cloud interactions

  2018cited by this paper
• The effect of secondary ice production parameterization on the simulation of a cold frontal rainband

  2018influential reference
• Secondary Ice Formation during Freezing of Levitated Droplets

  2018cited by this paper
• The Horizontal Ice Nucleation Chamber (HINC): INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch

  2017cited by this paper
• PathfinderTURB: an automatic boundary layer algorithm. Development, validation and application to study the impact on in situ measurements at the Jungfraujoch

  2017influential reference
• Initiation of secondary ice production in clouds

  2017cited by this paper
• Impact of surface and near-surface processes on ice crystal concentrations measured at mountain-top research stations

  2017cited by this paper
• Microbial ice nucleators scavenged from the atmosphere during simulated rain events

  2017cited by this paper
• The unstable ice nucleation properties of Snomax® bacterial particles

  2016cited by this paper
• Secondary Ice Production: Current State of the Science and Recommendations for the Future

  2016cited by this paper
• Technical Note: A proposal for ice nucleation terminology

  2015cited by this paper
• Revisiting ice nucleation from precipitation samples

  2015cited by this paper
• Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign

  2015cited by this paper
• The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch

  2015cited by this paper
• Influence of Liquid Water Content and Temperature on the Form and Growth of Branched Planar Snow Crystals in a Cloud

  2014influential reference
• Minimal cooling rate dependence of ice nuclei activity in the immersion mode

  2013cited by this paper
• Freezing nucleation apparatus puts new slant on study of biological ice nucleators in precipitation

  2013cited by this paper
• Fiji: an open-source platform for biological-image analysis

  2012cited by this paper
• Indications for stellar-crystal fragmentation in Arctic clouds

  2009cited by this paper
• The Growth of Atmospheric Ice Crystals: A Summary of Findings in Vertical Supercooled Cloud Tunnel Studies

  1999cited by this paper
• Breakup of levitated frost particles

  1998cited by this paper
• Ice forming nuclei in the high Arctic

  1996cited by this paper
• Possible High Ice Particle Production during Graupel–Graupel Collisions

  1995cited by this paper
• Vapor Diffusional Growth of Free-Falling Snow Crystals between -3 and -23°C

  1991cited by this paper
• Ice Crystal Production by Mountain Surfaces

  1987cited by this paper
• A laboratory study of secondary ice particle production by the fragmentation of rime and vapour-grown ice crystals

  1986cited by this paper
• Ice particle concentrations in clouds

  1985cited by this paper
• The Generation of Secondary Ice Particles in Clouds by Crystal–Crystal Collision

  1978cited by this paper
• Production of secondary ice particles during the riming process

  1974cited by this paper
• Supercooling of Water and Nucleation of Ice (Drop Freezer)

  1971cited by this paper
• Quantitative Evaluation of Experimental Results an the Heterogeneous Freezing Nucleation of Supercooled Liquids

  1971cited by this paper
• Shattering of Frozen Water Drops in a Supercooled Cloud

  1970cited by this paper
• Meteorological Classification of Natural Snow Crystals

  1966cited by this paper
• What is the Role of Ice in Summer Rain-Showers?.

  1964cited by this paper
• Nuclei in Snow and Ice Crystals on the Greenland Ice Cap under Natural and Artificially Stimulated Conditions

  1962cited by this paper
• The Temperature Conditions for the Growth of Natural and Artificial Snow Crystals

  1962cited by this paper
• A Laboratory Study of Atmospheric Ice Particles

  1962cited by this paper
• SNOW CRYSTALS AND THE IDENTIFICATION OF THE NUCLEI IN THE NORTHERN UNITED STATES OF AMERICA

  1961cited by this paper
• Snow crystals, natural and artificial

  1954cited by this paper
• Simultaneous Observations of the Mass, Falling Velocity and Form of Individual Snow Crystals

  1935cited by this paper
• Repeatability and Randomness in Freezing Nucleation Repeatability and Randomness in Heterogeneous Freezing Nucleation Repeatability and Randomness in Freezing Nucleation

  year unknowncited by this paper

• No citing papers are available for this paper.