scholarly journals Exact and near backscattering measurements of the linear depolarisation ratio of various ice crystal habits generated in a laboratory cloud chamber

2016 ◽  
Vol 178 ◽  
pp. 361-378 ◽  
Author(s):  
Helen R. Smith ◽  
Paul J. Connolly ◽  
Ann R. Webb ◽  
Anthony J. Baran
Keyword(s):  
Cloud Chamber ◽  
Ice Crystal ◽  
Depolarisation Ratio ◽  
Ice Crystal Habits

Ice crystal habits from cloud chamber studies obtained by in-line holographic microscopy related to depolarization measurements

2009 ◽  
Vol 48 (30) ◽  
pp. 5811 ◽  
Author(s):  
Peter Amsler ◽  
Olaf Stetzer ◽  
Martin Schnaiter ◽  
Evelyn Hesse ◽  
Stefan Benz ◽  
...  
Keyword(s):  
Cloud Chamber ◽  
Ice Crystal ◽  
Holographic Microscopy ◽  
Chamber Studies ◽  
Ice Crystal Habits

scholarly journals Classification of Ice Crystal Habits Observed From Airborne Cloud Particle Imager by Deep Transfer Learning

2019 ◽  
Vol 6 (10) ◽  
pp. 1877-1886 ◽  
Author(s):  
Haixia Xiao ◽  
Feng Zhang ◽  
Qianshan He ◽  
Pu Liu ◽  
Fei Yan ◽  
...  
Keyword(s):  
Transfer Learning ◽  
Ice Crystal ◽  
Cloud Particle ◽  
Ice Crystal Habits

A Bulk Microphysics Parameterization with Multiple Ice Precipitation Categories

2005 ◽  
Vol 44 (4) ◽  
pp. 445-466 ◽  
Author(s):  
Jerry M. Straka ◽  
Edward R. Mansell
Keyword(s):  
Parameter Tuning ◽  
Precipitation Process ◽  
Ice Crystal ◽  
Cloud Droplets ◽  
Microphysics Scheme ◽  
Convective Storms ◽  
Single Moment ◽  
Warm Rain Process ◽  
Ice Crystal Habits ◽  
Cloud Ice

Abstract A single-moment bulk microphysics scheme with multiple ice precipitation categories is described. It has 2 liquid hydrometeor categories (cloud droplets and rain) and 10 ice categories that are characterized by habit, size, and density—two ice crystal habits (column and plate), rimed cloud ice, snow (ice crystal aggregates), three categories of graupel with different densities and intercepts, frozen drops, small hail, and large hail. The concept of riming history is implemented for conversions among the graupel and frozen drops categories. The multiple precipitation ice categories allow a range of particle densities and fall velocities for simulating a variety of convective storms with minimal parameter tuning. The scheme is applied to two cases—an idealized continental multicell storm that demonstrates the ice precipitation process, and a small Florida maritime storm in which the warm rain process is important.

A Classification of Ice Crystal Habits Using Combined Lidar and Scanning Polarimeter Observations during the SEAC4RS Campaign

2020 ◽  
Vol 37 (12) ◽  
pp. 2185-2196
Author(s):  
Natalie Midzak ◽  
John E. Yorks ◽  
Jianglong Zhang ◽  
Bastiaan van Diedenhoven ◽  
Sarah Woods ◽  
...  
Keyword(s):  
Atmospheric Composition ◽  
Crystal Habit ◽  
Ice Crystal ◽  
Cloud Physics ◽  
Cloud Particle ◽  
Clustering Technique ◽  
Ice Crystal Habits

AbstractUsing collocated NASA Cloud Physics Lidar (CPL) and Research Scanning Polarimeter (RSP) data from the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign, a new observational-based method was developed which uses a K-means clustering technique to classify ice crystal habit types into seven categories: column, plates, rosettes, spheroids, and three different type of irregulars. Intercompared with the collocated SPEC, Inc., Cloud Particle Imager (CPI) data, the frequency of the detected ice crystal habits from the proposed method presented in the study agrees within 5% with the CPI-reported values for columns, irregulars, rosettes, and spheroids, with more disagreement for plates. This study suggests that a detailed ice crystal habit retrieval could be applied to combined space-based lidar and polarimeter observations such as CALIPSO and POLDER in addition to future missions such as the Aerosols, Clouds, Convection, and Precipitation (A-CCP).

scholarly journals Riming Electrification in Hokuriku Winter Clouds and Comparison with Laboratory Observations

2017 ◽  
Vol 74 (2) ◽  
pp. 431-447 ◽  
Author(s):  
Tsutomu Takahashi ◽  
Soichiro Sugimoto ◽  
Tetsuya Kawano ◽  
Kenji Suzuki
Keyword(s):  
Water Content ◽  
Charge Separation ◽  
Cloud Water ◽  
Cloud Chamber ◽  
Separation Mechanism ◽  
Ice Crystal ◽  
Content Domain ◽  
Main Charge ◽  
Cloud Water Content ◽  
Low Cloud

Abstract Riming electrification is the main charge separation mechanism of thunderstorms, occurring mainly during graupel particle–ice crystal collisions. Laboratory experiments have found that charge separation polarity and magnitude depend critically on cloud water content and temperature. Several groups have mapped this dependence, but there are substantial differences between their results. These conflicting laboratory-derived riming electrification topographies can be tested by comparing them to field observations. Here, direct and simultaneous sonde-based measurement of both precipitation particle type and charge (videosonde) and cloud water content [hydrometeor videosonde (HYVIS)] in lightning-active Hokuriku winter clouds at Kashiwazaki, Niigata Prefecture, Japan, are reported. With decreasing height, summed graupel charge transitioned from negative to positive at a mean temperature of −11°C, and the mean peak cloud water content in the positive graupel domain was 0.4 g m−3. Thus, in cloud regions of relatively high temperature (≥−11°C) and low cloud water content (CWC; ≤0.4 g m−3), graupel particles were mainly positively charged. This result can be compared with those of laboratory riming experiments; for example, in this temperature/cloud water content domain, graupel electrification has been reported to be positive by Takahashi, largely negative in early reports using the Manchester cloud chamber, positive in later reports using the Cordoba and Manchester modified cloud chambers, and partially positive in a more recent report using the Cordoba cloud chamber.

scholarly journals Influence of particle size and shape on the backscattering linear depolarisation ratio of small ice crystals – cloud chamber measurements in the context of contrail and cirrus microphysics

2012 ◽  
Vol 12 (21) ◽  
pp. 10465-10484 ◽  
Author(s):  
M. Schnaiter ◽  
S. Büttner ◽  
O. Möhler ◽  
J. Skrotzki ◽  
M. Vragel ◽  
...  
Keyword(s):  
Scattered Light ◽  
Supercooled Liquid ◽  
Cloud Chamber ◽  
Ice Crystals ◽  
Laser Scattering ◽  
Depolarisation Ratio ◽  
Ice Particles ◽  
T Matrix ◽  
Institute Of Technology ◽  
The Impact

Abstract. The article presents the laser scattering and depolarisation instrument SIMONE that is installed at the large aerosol and cloud chamber facility AIDA of the Karlsruhe Institute of Technology. SIMONE uses a 488 nm cw laser to probe simulated atmospheric clouds by measuring the scattered light from the 1.8° and 178.2° directions. At 178.2°, the scattered light is analysed for the linear polarisation state to deduce the particle linear depolarisation ratio δp which is a common measurement parameter of atmospheric lidar applications. The optical setup and the mathematical formalism of the depolarisation detection concept are given. SIMONE depolarisation measurements in spheroidal hematite aerosol and supercooled liquid clouds are used to validate the instrument. SIMONE data from a series of AIDA ice nucleation experiments at temperatures between 195 and 225 K were analysed in terms of the impact of the ice particle microphysics on δp. We found strong depolarisation values of up to 0.4 in case of small growing and sublimating ice particles with volume equivalent diameters of only a few micrometers. Modelling runs with the T-matrix method showed that the measured depolarisation ratios can be accurately reproduced assuming spheroidal and cylindrical particles with a size distribution that has been constrained by IR extinction spectroscopy. Based on the T-matrix modelling runs, we demonstrate that in case of small ice crystals the SIMONE depolarisation results are representative for the lidar depolarisation ratio which is measured at exact backscattering direction of 180°. The relevance of our results for the interpretation of recent lidar observations in cirrus and contrails is discussed. In view of our results, the high depolarisation ratios observed by the spaceborne lidar CALIOP in the tropical upper troposphere might be a hint for the presence of small (sublimating) ice particles in the outflows of deep convective systems.

scholarly journals Clarification of the Water Saturation Represented on Ice Crystal Growth Diagrams

2015 ◽  
Vol 72 (7) ◽  
pp. 2608-2611 ◽  
Author(s):  
Médéric St-Pierre ◽  
Julie M. Thériault
Keyword(s):  
Air Temperature ◽  
Water Saturation ◽  
Atmospheric Conditions ◽  
Ice Crystal ◽  
Vapor Density ◽  
Long Time ◽  
Physics Literature ◽  
Definition Of ◽  
Ice Crystal Habits ◽  
Density Excess

It has been known for a long time that the shape of ice crystals depends on both the air temperature and the relative humidity of the environment. The relationships among these factors have been summarized in classification diagrams and are intensively referred to in the cloud physics literature. To put in perspective the atmospheric conditions in which the different ice crystal habits grow with respect to the level of saturation in the atmosphere, the vapor density excess and supersaturation with respect to ice at liquid water saturation have been included on those diagrams as a function of air temperature. Over the years, the definition of the water saturation included in those types of diagrams has been misdefined. The goal of this study is to show that an error has been introduced in the definition of the excess of water vapor with respect to ice.

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