Abstract. Mixed-phase clouds affect precipitation and radiation differently from liquid and ice clouds, posing greater challenges to their representation in numerical simulations. Recent laboratory experiments using the Pi Cloud Chamber explored cloud glaciation conditions based on increased injection of ice-nucleating particles. In this study, we use two approaches to reproduce the results of the laboratory experiments: a bulk scalar mixing model and large-eddy simulation (LES) with bin microphysics. The first approach assumes a well-mixed domain to provide an efficient assessment of the mean cloud properties for a wide range of conditions. The second approach resolves the energy-carrying turbulence, the particle size distribution, and their spatial distribution to provide more details. These modeling approaches enable a separate and detailed examination of liquid and ice properties, which is challenging in the laboratory. Both approaches demonstrate that, with an increased ice number concentration, the flow and microphysical properties exhibit the same changes in trends. Additionally, both approaches show that the ice integral radius reaches the theoretical glaciation threshold when the cloud is subsaturated with respect to liquid water. The main difference between the results of the two approaches is that the bulk model allows for the complete glaciation of the cloud. However, LES reveals that, in a dynamic system, the cloud is not completely glaciated as liquid water droplets are continuously produced near the warm lower boundary and subsequently mixed into the chamber interior. These results highlight the importance of the ice mass fraction in distinguishing the mixed-phase clouds and ice clouds.
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A phase separation inlet for droplets, ice residuals, and interstitial aerosol particles
Abstract. A new inlet for studying the aerosol particles andhydrometeor residuals that compose mixed-phase clouds – the phaSeseParation Inlet for Droplets icE residuals and inteRstitial aerosolparticles (SPIDER) – is described here. SPIDER combines a large pumpedcounterflow virtual impactor (L-PCVI), a flow tube evaporation chamber, anda pumped counterflow virtual impactor (PCVI) to separate droplets, icecrystals (∼3–25 µm), and interstitial aerosolparticles for simultaneous sampling. Laboratory verification tests of eachindividual component and the composite SPIDER system were conducted.Transmission efficiency, evaporation, and ice crystals' survival weredetermined to show the capability of the system. The experiments show theSPIDER system can separate distinct cloud elements and interstitial aerosolparticles for subsequent analysis. As a field instrument, SPIDER will helpexplore the properties of different cloud elements and interstitial aerosolparticles in mixed-phase clouds.
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- Award ID(s):
- 1749865
- PAR ID:
- 10347632
- Date Published:
- Journal Name:
- Atmospheric Measurement Techniques
- Volume:
- 15
- Issue:
- 10
- ISSN:
- 1867-8548
- Page Range / eLocation ID:
- 3213 to 3222
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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