The Theoretical Basis for the Parameterization of Ice Crystal Habits: Growth by Vapor Deposition

Chen, Jen‐Ping; Lamb, Dennis

doi:10.1175/1520-0469(1994)051<1206:ttbftp>2.0.co;2

Cited by 114 publications

(179 citation statements)

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“…Note that in both runs shown, at −15 • C, the crystal habit has an aspect ratio of around 1/50, which denotes thin planar habits/or dendrites. This aspect ratio was calculated due to the low value of the inherent growth ratio, suggested by Chen and Lamb (1994a), that was used at this temperature, (−15) = 0.45.…”

Section: Model Resultsmentioning

confidence: 99%

“…The ice particle crystal volume changes in the following way: when droplets freeze to form ice crystals their density is set to that of pure ice ∼ 910 kg m −3 ; following growth by diffusion (with ventilation coefficients from Ji and Wang, 1999) the crystal density changes based on the model described by Chen and Lamb (1994a) and the volume added to the crystal is equal to the change in its mass divided by the "deposition density". As described by Chen and Lamb, the density of deposited vapour on the crystal decreases as the vapour excess increases over 0.05 g m −3 ; this reflects the fact that crystals exhibit "branching" at high supersaturations (Libbrecht, 2005, and cf.…”

Section: Description Of Microphysics Within the Modelmentioning

confidence: 99%

“…There is recent experimental evidence that facets develop due to this difference in the deposition coefficient on each of the crystallographic faces at low supersaturations, however other factors, such as dislocations and other defects may affect faceting at higher supersaturations (Libbrecht, 2005). Nevertheless the Chen and Lamb (1994a) model parameterises the fact that columnar shapes are likely to grow at −5 • C, planar crystals at −15 • C and columns at −25 • C.…”

Section: Description Of Microphysics Within the Modelmentioning

confidence: 99%

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A laboratory investigation into the aggregation efficiency of small ice crystals

2012

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Abstract. The aggregation of ice crystals and its temperature dependence is studied in the laboratory using a large ice cloud chamber. This process is important to the evolution of ice clouds in earth's atmosphere, yet there have been relatively few laboratory studies quantifying this parameter and its dependence on temperature. A detailed microphysical model is used to interpret the results from the experiments and derive best estimates for the aggregation efficiency as well as error bars. Our best estimates for the aggregation efficiency, at temperatures other than −15 • C, (in the interval −30 ≤ T ≤ 5 • C) are mostly in agreement with previous findings, which were derived using a very different approach to that described here. While the errors associated with such experiments are reasonably large, statistically, at temperatures other than −15, we are able to rule out aggregation efficiencies larger than 0.5 at the 75th percentile and rule out nonzero values at −15 • C, whereas at −15 • C we can rule out values higher than 0.85 and values lower than 0.35. The values of the aggregation efficiency shown here may be used in model studies of aggregation, but care must be taken that they only apply for the initial stages of aggregate growth, with humidities at or close to water saturation, and for particles up to a maximum size of ∼500 µm. They may therefore find useful application for modelling supercooled mid-level layer clouds that contain ice crystals, which are known to be important radiatively.

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Section: Model Resultsmentioning

confidence: 99%

Section: Description Of Microphysics Within the Modelmentioning

confidence: 99%

Section: Description Of Microphysics Within the Modelmentioning

confidence: 99%

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A laboratory investigation into the aggregation efficiency of small ice crystals

2012

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“…The shape, density, and growth rate of individual crystals are mostly a function of temperature and relative humidity of the environment in which they form (Magono and Lee, 1966;Chen and Lamb, 1994;Fukuta and Takahashi, 1999;Bailey and Hallett, 2009;Takahashi, 2014). Individual crystals can clump together (aggregation) and/or collect supercooled liquid water droplets that freeze upon impact on the surface of the crystals (riming).…”

Section: Introductionmentioning

confidence: 99%

Polarimetric radar and in situ observations of riming and snowfall microphysics during CLACE 2014

et al. 2015

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Abstract. This study investigates the microphysics of winter alpine snowfall occurring in mixed-phase clouds in an inner-Alpine valley during January and February 2014. The available observations include high-resolution polarimetric radar and in situ measurements of the ice-phase and liquidphase components of clouds and precipitation. Radar-based hydrometeor classification suggests that riming is an important factor to favor an efficient growth of the precipitating mass and correlates with snow accumulation rates at ground level. The time steps during which rimed precipitation is dominant are analyzed in terms of temporal evolution and vertical structure. Snowfall identified as rimed often appears after a short time period during which the atmospheric conditions favor wind gusts and updrafts and supercooled liquid water (SLW) is available. When a turbulent atmospheric layer persists for several hours and ensures continuous SLW generation, riming can be sustained longer and large accumulations of snow at ground level can be generated. The microphysical interpretation and the meteorological situation associated with one such event are detailed in the paper. The vertical structure of polarimetric radar observations during intense snowfall classified as rimed shows a peculiar maximum of specific differential phase shift K dp , associated with large number concentrations and riming of anisotropic crystals. Below this K dp peak there is usually an enhancement in radar reflectivity Z H , proportional to the K dp enhancement and interpreted as aggregation of ice crystals. These signatures seem to be recurring during intense snowfall.

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“…All studies show that plates are the preferred growth habit of ice crystals for the temperature ranges À4°C < T < 0 and À22°C < T À8°C. However, while a majority of studies find that columns predominate between À40°C < T < À22°C [Kumai, 1982;Takahashi et al, 1991;Chen and Lamb, 1994;Nelson and Knight, 1998;Fukuta and Takahashi, 1999;Wood et al, 2001], and this is the phase assumption employed in the retrieval technique described here, Bailey and Hallett [2004] argue instead that plates dominate in this regime. Therefore, as will be described in section 4, the sensitivity of precipitation retrievals to crystal habit assumptions is tested by switching the habit assumption across all temperature ranges.…”

Section: Particle Habitmentioning

confidence: 99%

Ground‐based remote sensing of precipitation in the Arctic

Zhao

Garrett

2008

J. Geophys. Res.

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[1] In this paper, a simple technique is described for application of radar to retrievals of vertical profiles of precipitation in the Arctic. The method is applied specifically to data from the DOE Atmospheric Radiation Measurement (ARM) North Slope of AlaskaAdjacent Arctic Ocean (NSA-AAO) site near Barrow, Alaska. Profiles of precipitation characteristic size are obtained by developing a relationship between particle size and particle fall speed derived from 35 GHz Doppler radar. The relationship depends on an assumed size-and temperature-dependent particle morphology tailored to the Arctic. Error analysis indicates that typical uncertainties in the precipitation retrieval rate are, to 95% confidence, about 40% for ice and 15% for liquid, although they can be as high as a factor of 2. Monthly averaged precipitation retrievals show strong seasonal variation and compare to within respective uncertainties with local ground-based National Weather Service and ARM NSA-AAO surface measurements. Measurements of precipitation profiles show substantial evaporation of precipitation to the atmosphere below cloud base. Associated atmospheric cooling can be several K d À1 , suggesting it may be a substantial component of the boundary layer energy budget in the Arctic.

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The Theoretical Basis for the Parameterization of Ice Crystal Habits: Growth by Vapor Deposition

Cited by 114 publications

References 0 publications

A laboratory investigation into the aggregation efficiency of small ice crystals

A laboratory investigation into the aggregation efficiency of small ice crystals

Polarimetric radar and in situ observations of riming and snowfall microphysics during CLACE 2014

Ground‐based remote sensing of precipitation in the Arctic

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