Journal ArticleDOI
High‐frequency gravity waves and homogeneous ice nucleation in tropical tropopause layer cirrus
Eric J. Jensen,Rei Ueyama,Leonhard Pfister,T. V. Bui,M. Joan Alexander,Aurélien Podglajen,Albert Hertzog,Sarah Woods,R. Paul Lawson,Ji-Eun Kim,Mark R. Schoeberl +10 more
TLDR
In this article, the impact of high-frequency gravity waves on homogeneous-freezing ice nucleation in cold cirrus clouds is examined using parcel model simulations driven by superpressure balloon measurements of temperature variability experienced by air parcels in the tropical tropopause region.Abstract:
The impact of high-frequency gravity waves on homogeneous-freezing ice nucleation in cold cirrus clouds is examined using parcel model simulations driven by superpressure balloon measurements of temperature variability experienced by air parcels in the tropical tropopause region. We find that the primary influence of high-frequency waves is to generate rapid cooling events that drive production of numerous ice crystals. Quenching of ice nucleation events by temperature tendency reversal in the highest-frequency waves does occasionally produce low ice concentrations, but the overall impact of high-frequency waves is to increase the occurrence of high ice concentrations. The simulated ice concentrations are considerably higher than indicated by in situ measurements of cirrus in the tropical tropopause region. One-dimensional simulations suggest that although sedimentation reduces mean ice concentrations, a discrepancy of about a factor of 3 with observed ice concentrations remains. Reconciliation of numerical simulations with the observed ice concentrations will require inclusion of physical processes such as heterogeneous nucleation and entrainment.read more
Citations
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A Study on the Wide Range of Relative Humidity in Cirrus Clouds Using Large-Ensemble Parcel Model Simulations
TL;DR: In this article , the impact of vertical motion and ice crystal deposition/sublimation on the wide range of relative humidity in cirrus clouds was investigated through in situ observations and parcel model simulations.
Journal ArticleDOI
A simple model to assess the impact of gravity waves on ice-crystal populations in the tropical tropopause layer
TL;DR: In this article , the role of gravity waves on microphysics of tropical cirrus clouds and air-parcel dehydration was studied using the combination of Lagrangian observations of temperature fluctuations and a 1.5D model.
Journal ArticleDOI
Ice fog observed at cirrus temperatures at Dome C, Antarctic Plateau
Etienne Vignon,L. Raillard,Christophe Genthon,Massimo Del Guasta,Andrew J. Heymsfield,Jean-Baptiste Madeleine,Alexis Berne +6 more
TL;DR: In this paper , the authors carried out an observational analysis of two shallow fog clouds forming in situ at cirrus temperatures, that is, temperatures lower than 235 K, at Dome-C, inner Antarctic Plateau.
Journal ArticleDOI
Does prognostic seeding along flight tracks produce the desired effects of cirrus cloud thinning?
TL;DR: In this paper , the authors used the ECHAM-HAM (Hamburg Aerosol Module) GCM to simulate CCT using a fully prognostic cirrus seeding aerosol species.
References
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Journal ArticleDOI
Water activity as the determinant for homogeneous ice nucleation in aqueous solutions
TL;DR: This work shows from experimental data that the homogeneous nucleation of ice from supercooled aqueous solutions is independent of the nature of the solute, but depends only on the water activity of the solution, and presents a thermodynamic theory for homogeneous ice nucleation, which expresses the nucleation rate coefficient as a function of water activity and pressure.
Journal ArticleDOI
Clarifying the Dominant Sources and Mechanisms of Cirrus Cloud Formation
Daniel J. Cziczo,Karl D. Froyd,Karl D. Froyd,Corinna Hoose,Eric J. Jensen,Minghui Diao,Mark A. Zondlo,Jessica B. Smith,Cynthia H. Twohy,Daniel M. Murphy +9 more
TL;DR: Results demonstrate that mineral dust and metallic particles are the dominant source of residual particles, whereas sulfate and organic particles are underrepresented, and elemental carbon and biological materials are essentially absent.
Journal ArticleDOI
The 2D-S (Stereo) Probe: Design and Preliminary Tests of a New Airborne, High-Speed, High-Resolution Particle Imaging Probe
TL;DR: In this paper, the design, laboratory calibrations, and flight tests of a new optical imaging instrument, the twodimensional stereo (2D-S) probe, are presented.
Journal ArticleDOI
A parameterization of cirrus cloud formation: Homogeneous freezing of supercooled aerosols
Bernd Kärcher,Ulrike Lohmann +1 more
TL;DR: In this paper, the number of ice crystals formed via homogeneous freezing of aqueous solution droplets is rather insensitive to details of the aerosol size distribution, but increases rapidly with updraft velocity and decreases with temperature.
Journal ArticleDOI
Heterogeneous nucleation of ice particles on glassy aerosols under cirrus conditions
Benjamin J. Murray,T. W. Wilson,S. Dobbie,Zhiqiang Cui,Sardar M. R. K. Al-Jumur,Ottmar Möhler,Martin Schnaiter,Robert Wagner,Stefan Benz,M. Niemand,Harald Saathoff,Volker Ebert,Volker Ebert,Steven Wagner,Bernd Kärcher +14 more
TL;DR: In this paper, it was shown that heterogeneous nucleation of ice on glassy solution droplets is an important mechanism for ice nucleation in the tropical tropopause layer.
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