Physical Sciences and Mathematics Commons^™

A Single-Photon Lidar Observes Atmospheric Clouds At Decimeter Scales: Resolving Droplet Activation Within Cloud Base, Fan Yang, Alexander B. Kostinski, Zeen Zhu, Katia Lamer, Edward Luke, Pavlos Kollias, Yong Meng Sua, Pei Hou, Raymond Shaw, Andrew M. Vogelmann

Michigan Tech Research Data

Clouds, crucial for understanding climate, begin with droplet formation from aerosols, but observations of this fleeting activation step are lacking in the atmosphere. Here we use a time-gated time-correlated single-photon counting lidar to observe cloud base structures at decimeter scales. Results show that the air-cloud interface is not a perfect boundary but rather is a transition zone where transformation of aerosol particles into cloud droplets occurs. The observed distributions of first-arriving photons within the transition zone reflect vertical development of a cloud, including droplet activation and condensational growth. Further, the highly resolved vertical profile of backscattered photons above cloud base …

Data Supporting The Paper "Droplet Growth Or Evaporation Does Not Buffer The Variability In Supersaturation In Clean Clouds", Jesse Anderson, Ian Helman, Raymond Shaw, Will Cantrell

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Water vapor supersaturation in clouds is a random variable that drives activation and growth of cloud droplets. The Pi Convection-Cloud Chamber generates a turbulent cloud with a microphysical steady-state that can be varied from clean to polluted by adjusting the aerosol injection rate. The supersaturation distribution and its moments, e.g., mean and variance, are investigated for varying cloud microphysical conditions. High-speed and co-located Eulerian measurements of temperature and water vapor concentration are combined to obtain the temporally resolved supersaturation distribution. This allows quantification of the contributions of variances and covariances between water vapor and temperature. Results are consistent with expectations …

Cloud Microphysical Response To Entrainment And Mixing Is Locally Inhomogeneous And Globally Homogeneous: Evidence From The Lab, Jaemin Yeom, Ian Helman, Prasanth Prabhakaran, Jesse Anderson, Fan Yang, Raymond Shaw, Will Cantrell

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The effects of entrainment-mixing on the cloud droplet size distribution are examined in the Pi cloud chamber that creates a turbulent supersaturated environment for cloud formation. The experiments are conducted with a temperature-controlled flange to mimic the entrainment-mixing process. The entrainment zone is created at the center of the top surface of the chamber, allowing dry air of controlled temperature (T_e) and flow rate (Q_e) to flow into the mixing cloud region. Due to the large-scale circulation, the downwind region is directly affected by entrained dry air from the flange, whereas the upwind region is representative …

Molecular Dynamics Simulation Data: Mw And Mlmw Water Model Ice Nucleation On A Hydrophilic Substrate With Negative Pressure, Will Cantrell, Tianshu Li, Issei Nakamura, Elise Rosky, Raymond Shaw

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This dataset contains the data supporting Figures in the study by Rosky et al., "Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension", submitted for publication in Atmospheric Chemistry and Physics in February 2023. Input files for reproducing the molecular dynamics simulations are included.

The abstract from the paper reads: Using a molecular model of water freezing on a hydrophilic substrate, it is found that heterogeneous ice nucleation rates occur at higher temperatures in water that is under tension, in other words under negative pressure. For pressures ranging from from 1 atm to …

An Intercomparison Of Large-Eddy Simulations Of A Convection Cloud Chamber Using Haze-Capable Bin And Lagrangian Cloud Microphysics Schemes, Fan Yang, Fabian Hoffmann, Raymond Shaw, Mikhail Ovchinnikov, Andrew Vogelmann

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Recent in-situ observations show that haze particles exist in a convection cloud chamber. The microphysics schemes previously used for large-eddy simulations of the cloud chamber could not fully resolve haze particles and the associated processes, including their activation and deactivation. Specifically, cloud droplet activation is modeled based on Twomey-type parameterizations, wherein cloud droplets are formed when a critical supersaturation for the available cloud condensation nuclei (CCN) is exceeded and haze particles are not explicitly resolved. Here, we develop and adapt haze-capable bin and Lagrangian microphysics schemes to properly resolve the activation and deactivation processes. Results are compared with the Twomey-type …

Ultrahigh Resolution Ote-Ms Data For Ambient Daytime And Nighttime Aerosol And Ambient Fog Water From San Pietro Capofiume, Matthew Brege, Lynn Mazzoleni

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This dataset and the methods used to obtain it are described in Chapter 3 of "EXTREME MOLECULAR DIVERSITY IN BIOMASS BURNING ATMOSPHERIC ORGANIC AEROSOL OBSERVED THROUGH ULTRAHIGH RESOLUTION MASS SPECTROMETRY" a Dissertation prepared by Matthew Brege and submitted as a Doctoral Thesis. This work can be accessed here: https://doi.org/10.37099/mtu.dc.etdr/927

Briefly, four days worth of concurrent daytime/nighttime aerosol and fog water samples were collected at San Pietro Capofiume in the Emilia Romagna region of Italy from 1-Dec to 4-Dec, 2015. The water soluble extracts of the aerosol filters and aliquots of the fog water were analyzed using ultrahigh resolution Orbitrap mass …

Ultrahigh Resolution Ote-Ms Data For Wildfire-Influenced Tar Ball Aerosol From The Pacific Northwest, Matthew Brege, Simeon Schum, Lynn Mazzoleni

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This dataset and the methods used to obtain it are described in Chapter 4 of "EXTREME MOLECULAR DIVERSITY IN BIOMASS BURNING ATMOSPHERIC ORGANIC AEROSOL OBSERVED THROUGH ULTRAHIGH RESOLUTION MASS SPECTROMETRY" a Dissertation prepared by Matthew Brege and submitted as a Doctoral Thesis. Access this associated work here: https://doi.org/10.37099/mtu.dc.etdr/927

Briefly, two samples of ambient aerosol were collected in the Pacific Northwest of the United States in 2017 which were heavily influenced by atmospheric tar balls. The acetonitrile soluble extracts of the aerosol filters were analyzed using ultrahigh resolution Orbitrap mass spectrometry (OTE-MS) using positive and negative modes of electrospray ionization as …

Data Supporting The Paper "Is The Water Vapor Supersaturation Distribution Gaussian?", Subin Thomas, Prasanth Prabhakaran, W. Cantrell, Raymond Shaw

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The data in this file are from the MTU Pi Cloud Chamber and large eddy simulations. This work was supported by NSF grant AGS-1754244. Data are made available in support of the above publication by Thomas et al.. For any further use, e.g., for publication elsewhere, the authors should be contacted to ensure the appropriate use of the data and proper acknowledgment.

Data In Support Of The Paper "Dependence Of Aerosol-Droplet Partitioning On Turbulence In A Laboratory Cloud", Abu Sayeed Md Shawon, Prasanth Prabhakaran, Gregory Kinney, Raymond Shaw, Will Cantrell

Michigan Tech Research Data

No abstract provided.