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Multi-View Polarimetric Scattering Cloud Tomography and Retrieval of Droplet Size. REMOTE SENSING 2020. [DOI: 10.3390/rs12172831] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Tomography aims to recover a three-dimensional (3D) density map of a medium or an object. In medical imaging, it is extensively used for diagnostics via X-ray computed tomography (CT). We define and derive a tomography of cloud droplet distributions via passive remote sensing. We use multi-view polarimetric images to fit a 3D polarized radiative transfer (RT) forward model. Our motivation is 3D volumetric probing of vertically-developed convectively-driven clouds that are ill-served by current methods in operational passive remote sensing. Current techniques are based on strictly 1D RT modeling and applied to a single cloudy pixel, where cloud geometry defaults to that of a plane-parallel slab. Incident unpolarized sunlight, once scattered by cloud-droplets, changes its polarization state according to droplet size. Therefore, polarimetric measurements in the rainbow and glory angular regions can be used to infer the droplet size distribution. This work defines and derives a framework for a full 3D tomography of cloud droplets for both their mass concentration in space and their distribution across a range of sizes. This 3D retrieval of key microphysical properties is made tractable by our novel approach that involves a restructuring and differentiation of an open-source polarized 3D RT code to accommodate a special two-step optimization technique. Physically-realistic synthetic clouds are used to demonstrate the methodology with rigorous uncertainty quantification.
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Mardi AH, Dadashazar H, MacDonald AB, Crosbie E, Coggon MM, Aghdam MA, Woods RK, Jonsson HH, Flagan RC, Seinfeld JH, Sorooshian A. Effects of Biomass Burning on Stratocumulus Droplet Characteristics, Drizzle Rate, and Composition. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:12301-12318. [PMID: 33274175 PMCID: PMC7709909 DOI: 10.1029/2019jd031159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 10/29/2019] [Indexed: 05/30/2023]
Abstract
This study reports on airborne measurements of stratocumulus cloud properties under varying degrees of influence from biomass burning (BB) plumes off the California coast. Data are reported from five total airborne campaigns based in Marina, California, with two of them including influence from wildfires in different areas along the coast of the western United States. The results indicate that subcloud cloud condensation nuclei number concentration and mass concentrations of important aerosol species (organics, sulfate, nitrate) were better correlated with cloud droplet number concentration (N d) as compared to respective above-cloud aerosol data. Given that the majority of BB particles resided above cloud tops, this is an important consideration for future work in the region as the data indicate that the subcloud BB particles likely were entrained from the free troposphere. Lower cloud condensation nuclei activation fractions were observed for BB-impacted clouds as compared to non-BB clouds due, at least partly, to less hygroscopic aerosols. Relationships between N d and either droplet effective radius or drizzle rate are preserved regardless of BB influence, indicative of how parameterizations can exhibit consistent skill for varying degrees of BB influence as long as N d is known. Lastly, the composition of both droplet residual particles and cloud water changed significantly when clouds were impacted by BB plumes, with differences observed for different fire sources stemming largely from effects of plume aging time and dust influence.
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Affiliation(s)
- Ali Hossein Mardi
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Hossein Dadashazar
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Alexander B MacDonald
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Ewan Crosbie
- Science Systems and Applications, Inc., Hampton, VA, USA
- NASA Langley Research Center, Hampton, VA, USA
| | - Matthew M Coggon
- Cooperative Institute for Research in Environmental Science and National Oceanic and Atmospheric Administration, Boulder, CO, USA
| | - Mojtaba Azadi Aghdam
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Roy K Woods
- Naval Postgraduate School, Monterey, CA, USA
| | | | - Richard C Flagan
- Department of Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - John H Seinfeld
- Department of Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Armin Sorooshian
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
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Chandrakar KK, Cantrell W, Shaw RA. Influence of Turbulent Fluctuations on Cloud Droplet Size Dispersion and Aerosol Indirect Effects. JOURNAL OF THE ATMOSPHERIC SCIENCES 2018; 75:3191-3209. [PMID: 30631213 PMCID: PMC6322217 DOI: 10.1175/jas-d-18-0006.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Cloud droplet relative dispersion, defined as the standard deviation over the mean cloud droplet size, is of central importance in determining and understanding aerosol indirect effects. In recent work, it was found that cloud droplet size distributions become broader as a result of supersaturation variability and that the sensitivity of this effect is inversely related to cloud droplet number density. The subject is investigated in further detail using an extensive dataset from a laboratory cloud chamber capable of producing steady-state turbulence. An extended stochastic theory is found to successfully describe properties of the droplet size distribution, including an analytical expression for the relative dispersion. The latter is found to depend on the cloud droplet removal time, which in turn increases with the cloud droplet number density. The results show that relative dispersion decreases monotonically with increasing droplet number density, consistent with some recent atmospheric observations. Experiments spanning fast to slow microphysics regimes are reported. The observed dispersion is used to estimate time scales for autoconversion, demonstrating the important role of the turbulence-induced broadening effect on precipitation development. An initial effort is made to extend the stochastic theory to an atmospheric context with a steady updraft, for which autoconversion time is the controlling factor for droplet lifetime. As in the cloud chamber, relative dispersion is found to increase with decreasing cloud droplet number density.
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Affiliation(s)
- K K Chandrakar
- Atmospheric Sciences Program, and Department of Physics, Michigan Technological University, Houghton, Michigan
| | - W Cantrell
- Atmospheric Sciences Program, and Department of Physics, Michigan Technological University, Houghton, Michigan
| | - R A Shaw
- Atmospheric Sciences Program, and Department of Physics, Michigan Technological University, Houghton, Michigan
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Chandrakar KK, Cantrell W, Kostinski AB, Shaw RA. Dispersion Aerosol Indirect Effect in Turbulent Clouds: Laboratory Measurements of Effective Radius. GEOPHYSICAL RESEARCH LETTERS 2018; 45:10738-10745. [PMID: 30778268 PMCID: PMC6376200 DOI: 10.1029/2018gl079194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Cloud optical properties are determined not only by the number density n d and mean radius r ¯ of cloud droplets but also by the shape of the droplet size distribution. The change in cloud optical depth with changing n d , due to the change in distribution shape, is known as the dispersion effect. Droplet relative dispersion is defined as d = σ r / r ¯ . 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 n d for a nonprecipitating cloud, hence nearly zero albedo susceptibility due to the dispersion effect. However, for size-dependent removal, such as in a laboratory cloud or highly clean atmospheric conditions, stochastic condensation produces a weak dispersion effect. The albedo susceptibility due to turbulence broadening has the same sign as the Twomey effect and augments it by order 10%.
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Affiliation(s)
- K. K. Chandrakar
- Atmospheric Sciences Program and Department of Physics, Michigan Technological University, Houghton, MI, USA
| | - W. Cantrell
- Atmospheric Sciences Program and Department of Physics, Michigan Technological University, Houghton, MI, USA
| | - A. B. Kostinski
- Atmospheric Sciences Program and Department of Physics, Michigan Technological University, Houghton, MI, USA
| | - R. A. Shaw
- Atmospheric Sciences Program and Department of Physics, Michigan Technological University, Houghton, MI, USA
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Schmidt J, Wandinger U, Malinka A. Dual-field-of-view Raman lidar measurements for the retrieval of cloud microphysical properties. APPLIED OPTICS 2013; 52:2235-47. [PMID: 23670751 DOI: 10.1364/ao.52.002235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/17/2013] [Indexed: 05/26/2023]
Abstract
Dual-field-of-view Raman lidar measurements, detecting Raman-scattered light with two fields of view simultaneously, are used for the first time to retrieve cloud microphysical properties. The measurements are performed with the Multiwavelength Atmospheric Raman Lidar for Temperature, Humidity, and Aerosol Profiling (MARTHA) at the Leibniz Institute for Tropospheric Research in Leipzig, Germany. Light that is scattered in forward direction by cloud droplets and inelastically backscattered by N2 molecules is detected. A forward iterative algorithm uses the measured signals to derive profiles of the effective cloud droplet radius, extinction coefficient, and liquid-water content of the investigated clouds. The setup, algorithm, error analysis, and a measurement example are presented. The obtained liquid-water path is validated by observations with a microwave radiometer. With the capability to retrieve aerosol properties as well as cloud microphysical properties, the Raman lidar MARTHA is an ideal tool for studies of the aerosol indirect effect.
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Affiliation(s)
- Jörg Schmidt
- Leibniz Institute for Tropospheric Research, Leipzig 04318, Germany.
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Koike M, Takegawa N, Moteki N, Kondo Y, Nakamura H, Kita K, Matsui H, Oshima N, Kajino M, Nakajima TY. Measurements of regional-scale aerosol impacts on cloud microphysics over the East China Sea: Possible influences of warm sea surface temperature over the Kuroshio ocean current. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd017324] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wonaschuetz A, Sorooshian A, Ervens B, Chuang PY, Feingold G, Murphy SM, de Gouw J, Warneke C, Jonsson HH. Aerosol and gas re-distribution by shallow cumulus clouds: An investigation using airborne measurements. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd018089] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pandithurai G, Dipu S, Prabha TV, Maheskumar RS, Kulkarni JR, Goswami BN. Aerosol effect on droplet spectral dispersion in warm continental cumuli. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016532] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Distribution and origin of aerosol and its transform relationship with CCN derived from the spring multi-aircraft measurements of Beijing Cloud Experiment (BCE). ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11434-012-5136-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Morales R, Nenes A, Jonsson H, Flagan RC, Seinfeld JH. Evaluation of an entraining droplet activation parameterization using in situ cloud data. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015324] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Barahona D, Sotiropoulou R, Nenes A. Global distribution of cloud droplet number concentration, autoconversion rate, and aerosol indirect effect under diabatic droplet activation. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015274] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Anttila T. Sensitivity of cloud droplet formation to the numerical treatment of the particle mixing state. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jd013995] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lu ML, Sorooshian A, Jonsson HH, Feingold G, Flagan RC, Seinfeld JH. Marine stratocumulus aerosol-cloud relationships in the MASE-II experiment: Precipitation susceptibility in eastern Pacific marine stratocumulus. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009jd012774] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lance S, Nenes A, Mazzoleni C, Dubey MK, Gates H, Varutbangkul V, Rissman TA, Murphy SM, Sorooshian A, Flagan RC, Seinfeld JH, Feingold G, Jonsson HH. Cloud condensation nuclei activity, closure, and droplet growth kinetics of Houston aerosol during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS). ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd011699] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Parrish DD, Allen DT, Bates TS, Estes M, Fehsenfeld FC, Feingold G, Ferrare R, Hardesty RM, Meagher JF, Nielsen-Gammon JW, Pierce RB, Ryerson TB, Seinfeld JH, Williams EJ. Overview of the Second Texas Air Quality Study (TexAQS II) and the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS). ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009jd011842] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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