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Vaughan Phillips

Research in the Area of Clouds, Aerosols and Climate

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Fragmentation in Collisions of Snow with Graupel/Hail : New Formulation from Field Observations

Author

  • Martanda Gautam
  • Deepak Waman
  • Sachin Patade
  • Akash Deshmukh
  • Vaughan Phillips
  • Marcin Jackowicz-Korczynski
  • Freddy Pazhambilly Paul
  • Paul Smith
  • Aaron Bansemer

Summary, in English

Secondary ice production (SIP) has been attributed to the generation of most ice particles observed in precipitating clouds with cloud tops warmer than 2368C, from various aircraft- and ground-based field observations across the globe. One of the known SIP mechanisms is fragmentation during collisions among ice particles. It has been studied with our theoretical formulation, which has been applied in microphysical schemes of atmospheric models in a few studies. These have predicted an extensive impact on cloud glaciation and radiative properties. However, there has been a lack of experimental field studies, especially involving naturally falling snowflakes, to better understand this particular mechanism of SIP. This study reports the first field measurements with modern technology for fragmentation during collisions between naturally falling snowflakes and graupel/hail particles. This was observed with an innovatively designed portable chamber that was deployed outdoors in northern Sweden. Applying the observations from this field-based study, we optimized the existing formulation for predicting numbers of fragments from collisions of snow with graupel/hail. The observations show the average numbers of fragments per collision for dendritic (3–12 mm) and nondendritic (1–3 mm) snow were about 12 and 1, respectively. This represents a boost of predicted fragment numbers relative to our original formulation published in 2017. The updated formulation for breakup in ice–ice collisions can be implemented in the microphysical schemes of atmospheric models.

Department/s

  • Dept of Physical Geography and Ecosystem Science
  • MERGE: ModElling the Regional and Global Earth system
  • eSSENCE: The e-Science Collaboration
  • BECC: Biodiversity and Ecosystem services in a Changing Climate

Publishing year

2024

Language

English

Pages

2149-2164

Publication/Series

Journal of the Atmospheric Sciences

Volume

81

Issue

12

Document type

Journal article

Publisher

Amer Meteorological Soc

Topic

  • Meteorology and Atmospheric Sciences

Keywords

  • Cloud microphysics
  • Cloud parameterizations
  • In situ atmospheric observations
  • Measurements
  • Optimization
  • Secondary ice production

Status

Published

ISBN/ISSN/Other

  • ISSN: 0022-4928