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Full-Text Articles in Physics
Scaling Of Turbulence And Microphysics In A Convection–Cloud Chamber Of Varying Height, Subin Thomas, Fan Yang, Mikhail Ovchinnikov, Will Cantrell, Raymond Shaw
Scaling Of Turbulence And Microphysics In A Convection–Cloud Chamber Of Varying Height, Subin Thomas, Fan Yang, Mikhail Ovchinnikov, Will Cantrell, Raymond Shaw
Michigan Tech Publications
The convection–cloud chamber enables measurement of aerosol and cloud microphysics, as well as their interactions, within a turbulent environment under steady-state conditions. Increasing the size of a convection–cloud chamber, while holding the imposed temperature difference constant, leads to increased Rayleigh, Reynolds and Nusselt numbers. Large–eddy simulation coupled with a bin microphysics model allows the influence of increased velocity, time, and spatial scales on cloud microphysical properties to be explored. Simulations of a convection–cloud chamber, with fixed aspect ratio and increasing heights of H = 1, 2, 4, and (for dry conditions only) 8 m are performed. The key findings are: …
The Consistent Behavior Of Tropical Rain: Average Reflectivity Vertical Profiles Determined By Rain Top Height, Reuven H. Heiblum, Ilan Koren, Orit Altaratz, Alexander Kostinski
The Consistent Behavior Of Tropical Rain: Average Reflectivity Vertical Profiles Determined By Rain Top Height, Reuven H. Heiblum, Ilan Koren, Orit Altaratz, Alexander Kostinski
Department of Physics Publications
Sixteen years of Tropical Rain Measuring Mission (TRMM) reflectivity profile data are collected for oceanic, continental, and island tropical regions within the boreal winter intertropical convergence zone (ITCZ). When sorted by the rain top height (RTH), a consistent behavior emerges where the average reflectivity profiles originating at different RTHs form non-overlapping manifolds in the height–reflectivity space, excluding the brightband regions for stratiform type profiles. Based on reflectivity slope (dBZ km−1) profile characteristics and physical considerations, the profiles are divided into three classes: 1) cold profiles, which originate above the −20°C isotherm height and display convergence to a …
Laboratory Measurements Of Contact Freezing By Dust And Bacteria At Temperatures Of Mixed-Phase Clouds, Joseph Niehaus, John Becker, Alexander Kostinski, Will Cantrell
Laboratory Measurements Of Contact Freezing By Dust And Bacteria At Temperatures Of Mixed-Phase Clouds, Joseph Niehaus, John Becker, Alexander Kostinski, Will Cantrell
Department of Physics Publications
Laboratory measurements of freezing by aerosol particles in contact mode are presented. The fraction of particles catalyzing freezing is quantified for three mineral dusts and three strains of bacteria. This is the most comprehensive such dataset to date for temperatures greater than −20°C, relevant for warm, mixed-phase clouds. For Arizona Test Dust, feldspar, or rhyolitic ash, more than 103 particles are required to initiate a freezing event at −20°C in the contact mode. At −15°C, more than 105 particles are required. An ice-negative strain of Pseudomonas fluorescens is an order of magnitude more effective than the mineral dusts …
Investigations Of Cloud Microphysical Response To Mixing Using Digital Holography, Matthew Jacob Beals
Investigations Of Cloud Microphysical Response To Mixing Using Digital Holography, Matthew Jacob Beals
Dissertations, Master's Theses and Master's Reports - Open
Cloud edge mixing plays an important role in the life cycle and development of clouds. Entrainment of subsaturated air affects the cloud at the microscale, altering the number density and size distribution of its droplets. The resulting effect is determined by two timescales: the time required for the mixing event to complete, and the time required for the droplets to adjust to their new environment. If mixing is rapid, evaporation of droplets is uniform and said to be homogeneous in nature. In contrast, slow mixing (compared to the adjustment timescale) results in the droplets adjusting to the transient state of …