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Articles 1 - 12 of 12
Full-Text Articles in Physics
Fine-Scale Droplet Clustering In Atmospheric Clouds: 3d Radial Distribution Function From Airborne Digital Holography, Michael L. Larsen, Raymond Shaw, Alexander Kostinski, Susanne Glienke
Fine-Scale Droplet Clustering In Atmospheric Clouds: 3d Radial Distribution Function From Airborne Digital Holography, Michael L. Larsen, Raymond Shaw, Alexander Kostinski, Susanne Glienke
Department of Physics Publications
The extent of droplet clustering in turbulent clouds has remained largely unquantified, and yet is of possible relevance to precipitation formation and radiative transfer. To that end, data gathered by an airborne holographic instrument are used to explore the three-dimensional spatial statistics of cloud droplet positions in homogeneous stratiform boundary-layer clouds. The three-dimensional radial distribution functions g(r) reveal unambiguous evidence of droplet clustering. Three key theoretical predictions are observed: the existence of positive correlations, onset of correlation in the turbulence dissipation range, and monotonic increase of g(r) with decreasing r. This implies that current theory captures the essential processes contributing …
Scale Dependence Of Cloud Microphysical Response To Turbulent Entrainment And Mixing, Bipin Kumar, Paul Gotzfried, Neethl Suresh, Jörg Schumacher, Raymond Shaw
Scale Dependence Of Cloud Microphysical Response To Turbulent Entrainment And Mixing, Bipin Kumar, Paul Gotzfried, Neethl Suresh, Jörg Schumacher, Raymond Shaw
Michigan Tech Publications
The dynamics and lifetime of atmospheric clouds are tightly coupled to entrainment and turbulent mixing. This paper presents direct numerical simulations of turbulent mixing followed by droplet evaporation at the cloud‐clear air interface in a meter‐sized volume, with an ensemble of up to almost half a billion individual cloud water droplets. The dependence of the mixing process on domain size reveals that inhomogeneous mixing becomes increasingly important as the domain size is increased. The shape of the droplet size distribution varies strongly with spatial scale, with the appearance of a pronounced negative exponential tail. The increase of relative dispersion during …
Turbulence Induced Cloud Voids: Observation And Interpretation, Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz
Turbulence Induced Cloud Voids: Observation And Interpretation, Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz
Department of Physics Publications
The phenomenon of cloud voids, i.e., elongated volumes inside a cloud that are devoid of droplets, was observed with laser sheet photography in clouds at a mountain-top station. Two experimental cases, similar in turbulence conditions yet with diverse droplet size distributions and cloud void prevalence, are reported. A theoretical explanation is proposed based on the study of heavy inertial sedimenting particles inside a Burgers vortex. A general conclusion regarding void appearance is drawn from theoretical analysis. Numerical simulations of polydisperse droplet motion with realistic vortex parameters and Mie scattering visual effects accounted for can explain the presence of voids with …
Molecular And Physical Characteristics Of Aerosol At A Remote Free Troposphere Site: Implications For Atmospheric Aging, Simeon Schum, Bo Zhang, Katja Džepina, Paolo Fialho, Claudio Mazzoleni, Lynn Mazzoleni
Molecular And Physical Characteristics Of Aerosol At A Remote Free Troposphere Site: Implications For Atmospheric Aging, Simeon Schum, Bo Zhang, Katja Džepina, Paolo Fialho, Claudio Mazzoleni, Lynn Mazzoleni
Department of Chemistry Publications
Aerosol properties are transformed by atmospheric processes during long-range transport and play a key role in the Earth's radiative balance. To understand the molecular and physical characteristics of free tropospheric aerosol, we studied samples collected at the Pico Mountain Observatory in the North Atlantic. The observatory is located in the marine free troposphere at 2225m above sea level, on Pico Island in the Azores archipelago. The site is ideal for the study of long-range-transported free tropospheric aerosol with minimal local influence. Three aerosol samples with elevated organic carbon concentrations were selected for detailed analysis. FLEXPART retroplumes indicated that two of …
Data Supporting The Paper "Turbulence Induced Cloud Voids: Observation And Interpretation", Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz
Data Supporting The Paper "Turbulence Induced Cloud Voids: Observation And Interpretation", Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz
Department of Physics Publications
No abstract provided.
Dispersion Aerosol Indirect Effect In Turbulent Clouds: Laboratory Measurements Of Effective Radius, K. K. Chandrakar, Will Cantrell, A. Kostinski, Raymond Shaw
Dispersion Aerosol Indirect Effect In Turbulent Clouds: Laboratory Measurements Of Effective Radius, K. K. Chandrakar, Will Cantrell, A. Kostinski, Raymond Shaw
Department of Physics Publications
Cloud optical properties are determined not only by the number density nd and mean radius ṝ of cloud droplets but also by the shape of the droplet size distribution. The change in cloud optical depth with changing nd, due to the change in distribution shape, is known as the dispersion effect. Droplet relative dispersion is defined as d=σr / ṝ . For the first time, a commonly used effective radius parameterization is tested in a controlled laboratory environment by creating a turbulent cloud. Stochastic condensation growth suggests d independent of nd for a nonprecipitating cloud, …
Data Supporting The Paper "Dispersion Aerosol Indirect Effect In Turbulent Clouds: Laboratory Measurements Of Effective Radius", K. K. Chandrakar, Will Cantrell, A. Kostinski, R. A. Shaw
Data Supporting The Paper "Dispersion Aerosol Indirect Effect In Turbulent Clouds: Laboratory Measurements Of Effective Radius", K. K. Chandrakar, Will Cantrell, A. Kostinski, R. A. Shaw
Department of Physics Publications
No abstract provided.
Simulation Data Supporting The Paper "Optical Properties And Radiative Forcing Of Fractal-Like Tar Ball Aggregates From Biomass Burning", Janarjan Bhandari, Swarup China, Giulia Girotto, Barbara Scarnato, Kyle Gorkowski, Allison Aiken, Manvendra Dubey, C. Mazzoleni
Simulation Data Supporting The Paper "Optical Properties And Radiative Forcing Of Fractal-Like Tar Ball Aggregates From Biomass Burning", Janarjan Bhandari, Swarup China, Giulia Girotto, Barbara Scarnato, Kyle Gorkowski, Allison Aiken, Manvendra Dubey, C. Mazzoleni
Department of Physics Publications
Simulations data supporting the paper "Optical properties and radiative forcing of fractal-like tar ball aggregates from biomass burning," to be submitted to the Journal of Quantitative Spectroscopy and Radiative Transfer.
Measurement And Modeling Of The Multiwavelength Optical Properties Of Uncoated Flame-Generated Soot, Sara D. Forestieri, Taylor M. Helgestad, Andrew T. Lambe, Lindsay Renbaum-Wolff, Paulo Massoli, Eben S. Cross, Claudio Mazzoleni, Et. Al.
Measurement And Modeling Of The Multiwavelength Optical Properties Of Uncoated Flame-Generated Soot, Sara D. Forestieri, Taylor M. Helgestad, Andrew T. Lambe, Lindsay Renbaum-Wolff, Paulo Massoli, Eben S. Cross, Claudio Mazzoleni, Et. Al.
Michigan Tech Publications
Optical properties of flame-generated black carbon (BC) containing soot particles were quantified at multiple wavelengths for particles produced using two different flames: a methane diffusion flame and an ethylene premixed flame. Measurements were made for (i) nascent soot particles, (ii) thermally denuded nascent particles, and (iii) particles that were coated and then thermally denuded, leading to the collapse of the initially lacy, fractal-like morphology. The measured mass absorption coefficients (MACs) depended on soot maturity and generation but were similar between flames for similar conditions. For mature soot, here corresponding to particles with volume-equivalent diameters >∼160 nm, the MAC and absorption …
Observation Of A Link Between Energy Dissipation Rate And Oscillation Frequency Of The Large-Scale Circulation In Dry And Moist Rayleigh-Bénard Turbulence, Dennis Niedermeier, Kelken Chang, Will Cantrell, Kamal Kant Chandrakar, David Ciochetto, Raymond Shaw
Observation Of A Link Between Energy Dissipation Rate And Oscillation Frequency Of The Large-Scale Circulation In Dry And Moist Rayleigh-Bénard Turbulence, Dennis Niedermeier, Kelken Chang, Will Cantrell, Kamal Kant Chandrakar, David Ciochetto, Raymond Shaw
Department of Physics Publications
In this study both the small- and large-scale flow properties of turbulent Rayleigh-Bénard convection are investigated. Experiments are carried out using the Π chamber (aspect ratio Γ=2) for Rayleigh number range Ra∼108–109 and Prandtl number Pr≈0.7. Furthermore, experiments are run for dry and wet conditions, i.e., top and bottom surfaces of the chamber are dry and wet, respectively. For wet conditions we further distinguish between conditions with and without the presence of sodium chloride aerosol particles which, if supersaturated conditions are achieved, lead to cloud droplet formation. We therefore refer to these conditions as moist and cloudy, …
A Method For Computing The Three-Dimensional Radial Distribution Function Of Cloud Particles From Holographic Images, Michael L. Larsen, Raymond Shaw
A Method For Computing The Three-Dimensional Radial Distribution Function Of Cloud Particles From Holographic Images, Michael L. Larsen, Raymond Shaw
Michigan Tech Publications
Reliable measurements of the three-dimensional radial distribution function for cloud droplets are desired to help characterize microphysical processes that depend on local drop environment. Existing numerical techniques to estimate this three-dimensional radial distribution function are not well suited to in situ or laboratory data gathered from a finite experimental domain. This paper introduces and tests a new method designed to reliably estimate the three-dimensional radial distribution function in contexts in which (i) physical considerations prohibit the use of periodic boundary conditions and (ii) particle positions are measured inside a convex volume that may have a large aspect ratio. The method …
Data Supporting The Paper "Influence Of Microphysical Variability On Stochastic Condensation In A Turbulent Laboratory Cloud", N. Desai, K. K. Chandrakar, K. Chang, Will Cantrell, Raymond Shaw
Data Supporting The Paper "Influence Of Microphysical Variability On Stochastic Condensation In A Turbulent Laboratory Cloud", N. Desai, K. K. Chandrakar, K. Chang, Will Cantrell, Raymond Shaw
Department of Physics Publications
No abstract provided.