PHIPS-HALO: the airborne particle habit imaging and polar scattering probe – Part 2: Characterization and first results

Schnaiter, M.; Järvinen, Emma; Abdelmonem, Ahmed; Leisner, Thomas

doi:10.5194/amt-11-341-2018

Cited by 39 publications

(49 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A sequence showing banding during growth at atmospheric pressure, −30 °C, and 8.8% supersaturation is in . Schnaiter et al (2018) shows the banding in hollow bullet rosettes from clouds and Nakaya et al (1958) shows numerous cases on hollow columns and sector-like forms. The bands are much denser in the latter forms.…”

Section: Mechanisms For Hollow Close-off Terracing and Banding 10mentioning

confidence: 99%

Air pockets and secondary habits in ice from lateral-type growth

Nelson

Swanson

2019

Preprint

View full text Add to dashboard Cite

Often overlooked in studies of ice growth is how the crystal faces grow laterally. This paper explores the implications of such lateral-type growth and how it may explain air pockets and other secondary features of vapor-grown ice in air. For example, using a new crystal-growth chamber, we observed air pockets forming at crystal corners when a sublimated crystal is regrown. This and other observations support the idea that the lateral spreading of a face, and its (in some cases) extension as a 10 thin overhang over the adjoining region, is driven by a flux of surface-mobile admolecules across the face to the lateral-growth front. Inspired by recent work on this topic by Prof. A. Yamashita of Osaka Kyoiku University, we call this flux "adjoining surface transport" (AST) and the extension overgrowth "protruding growth", then apply the concepts to observed ice and snow crystals, including some from a cloud chamber and others from our experiments. We also suggest that such lateral-type growth may explain other air pockets, droxtal centers in dendrites, hollow terracing and banding, multiple-capped columns, scrolls, 15 trigonals, and sheath clusters. For dendrites and sheaths, AST may increase their maximum dimensions and round their tips.

show abstract

Section: Mechanisms For Hollow Close-off Terracing and Banding 10mentioning

confidence: 99%

Air pockets and secondary habits in ice from lateral-type growth

Nelson

Swanson

2019

Preprint

View full text Add to dashboard Cite

show abstract

“…In these studies, the rates of approaching micron-scale layers, also known as macrosteps (arising from the clustering of smaller steps or contact between crystals of differing height) changed in a way consistent with a flux of molecules over the top edge of the layer. The AST concept has long been applied to the growth rates of metal whiskers (e.g., Sears, 1955;Avramov, 2007) but rarely to ice. More recent experiments on ice find evidence of the flux over the tops of much thinner layers (Asakawa et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Lateral facet growth of ice and snow – Part 1: Observations and applications to secondary habits

Nelson

Swanson

2019

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. Often overlooked in studies of ice growth is how the crystal facets increase in area, that is, grow laterally. This paper reports on observations and applications of such lateral facet growth for vapor-grown ice in air. Using a new crystal-growth chamber, we observed air pockets forming at crystal corners when a sublimated crystal is regrown. This observation indicates that the lateral spreading of a face can, under some conditions, extend as a thin overhang over the adjoining region. We argue that this extension is driven by a flux of surface-mobile molecules across the face to the lateral-growth front. Following the pioneering work on this topic by Akira Yamashita, we call this flux “adjoining surface transport” (AST) and the extension overgrowth “protruding growth”. Further experiments revealed other types of pockets that are difficult to explain without invoking AST and protruding growth. We develop a simple model for lateral facet growth on a tabular crystal in air, finding that AST is required to explain observations of facet spreading. Applying the AST concept to observed ice and snow crystals, we argue that AST promotes facet spreading, causes protruding growth, and alters layer nucleation rates. In particular, depending on the conditions, combinations of lateral- and normal-growth processes can help explain presently inexplicable secondary features and habits such as air pockets, small circular centers in dendrites, hollow structure, multiple-capped columns, scrolls, sheath clusters, and trigonals. For dendrites and sheaths, AST may increase their maximum dimensions and round their tips. Although these applications presently lack quantitative detail, the overall body of evidence here demonstrates that any complete model of ice growth from the vapor should include such lateral-growth processes.

show abstract

“…The Particle Habit Imaging and Polar Scattering probe (Abdelmonem et al, 2016) data were used to discriminate ice particles and droplets based on angular light scattering measurements (Schnaiter et al, 2018). The appearance of liquid droplets in clouds was defined when the LWC is greater than 0.005 g m −3 in a previous study by Baumgardner and Rodi (1989).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Cloud Microphysical Properties Derived From MODIS and Himawari‐8 Using In Situ Aircraft Measurements Over the Southern Ocean

Zhao

Wang

et al. 2020

Earth and Space Science

View full text Add to dashboard Cite

Cloud microphysical properties from aircraft measurements during the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study are used to evaluate the cloud products from the geostationary satellite Himawari-8 (H-8) and the polar-orbiting satellite the Moderate Resolution Imaging Spectroradiometer (MODIS). Compared to the in situ aircraft observations when aircraft flew horizontally near cloud tops, the cloud droplet effective radius (r e ) and number concentration (N d ) from H-8 (MODIS) are 33% (26%-31%) and 2% (9-13%) larger. Both the H-8 and MODIS retrievals behave similarly for liquid-only and mixed-phase low-level clouds, indicating the weak sensitivity of the satellite cloud retrieval performance to cloud phase. The r e and N d of the cloud profiles from aircraft measurements were also used to compare with the satellite product. It shows that H-8 r e and N d agree better with aircraft measurements when considering only the in situ data acquired in the upper portions (highest 20%) of the clouds. Roughly, the r e overestimation by H-8 decreases from 18% to 3% when considering the upper portions of clouds compared to all cloud layer averages, except for one case with drizzles appeared. In addition, the performance of MODIS r e and N d is highly dependent on the wavelengths the retrieval method uses. The droplet r e retrievals using wavelength of 1.6 μm have much larger biases than that using the other two channels. The potential effects of the cloud vertical variation and the photon penetration depth, the cloud heterogeneity, the cloud droplet size spectra, and the drizzle on satellite retrievals have also been discussed. is a co-corresponding author with Chuanfeng Zhao Key Points:• Himawari-8 (MODIS) cloud product overestimates r e near cloud top by 33% (26-31%) over Southern Ocean • Himawari8 r e and N d agree better with aircraft measurements when considering only the in situ data acquired in the upper portions of clouds • The performance of MODIS retrievals depends on the wavelength, with larger biases at 1.6 μm than 2.1 and 3.7 μm

show abstract

PHIPS-HALO: the airborne particle habit imaging and polar scattering probe – Part 2: Characterization and first results

Cited by 39 publications

References 19 publications

Air pockets and secondary habits in ice from lateral-type growth

Air pockets and secondary habits in ice from lateral-type growth

Lateral facet growth of ice and snow – Part 1: Observations and applications to secondary habits

Evaluation of Cloud Microphysical Properties Derived From MODIS and Himawari‐8 Using In Situ Aircraft Measurements Over the Southern Ocean

Contact Info

Product

Resources

About