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Browsing by Author "Light Scattering and Radiative Processes"
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A 3D implementation of ray tracing combined with diffraction on facets: Verification and a potential application
Clarke, A.J.M.; Hesse, E.; Ulanowski, Z.; Kaye, Paul H. (2006)A 3D implementation of a new model of light scattering applicable to dielectric faceted objects is introduced. The model combines standard geometric optics with diffraction on individual facets. It can be applied to any ... -
AIITS: Preliminary light scattering data from Tropical Tropopause Layer cirrus
Stopford, Chris; Kaye, Paul H.; Ulanowski, Joseph; Hirst, Edwin; Greenaway, Richard; Dorsey, James; Gallagher, Martin; Woods, Sarah; Lawson, Paul; Thornberry, Troy; Rollins, Drew; Harris, Neil (2015-07-22)The new optical particle spectrometer AIITS (Aerosol Ice Interface Transition Spectrometer) is the next instrument in the Small Ice Detector (SID) family. Like SID3, it acquires two-dimensional forward scattering patterns ... -
The applicability of physical optics in the millimetre and sub-millimetre spectral region. : Part I: The ray tracing with diffraction on facets method
Baran, Anthony; Hesse, Evelyn; Sourdeval, Odran (2017-03-01)Future satellite missions, from 2022 onwards, will obtain near-global measurements of cirrus at microwave and sub-millimetre frequencies. To realise the potential of these observations, fast and accurate light-scattering ... -
The applicability of physical optics in the millimetre and sub-millimetre spectral region. Part II: Application to a three-component model of ice cloud and its evaluation against the bulk single-scattering properties of various other aggregate models
Baran, Anthony; Ishimoto, Hiroshi; Sourdeval, Odran; Hesse, Evelyn; Harlow, Chawn (2018-02-28)The bulk single-scattering properties of various randomly oriented aggregate ice crystal models are com- pared and contrasted at a number of frequencies between 89 and 874 GHz. The model ice particles consist of the ... -
Application of RTDF to particles with curved surfaces
Hesse, E.; McCall, D.; Ulanowski, Z.; Stopford, C.; Kaye, Paul H. (2009)The applicability of the ray tracing with diffraction on facets model is extended to particles with curved surfaces. This allows tests against T-matrix calculations for larger size parameters and modelling of light scattering ... -
Application of RTDF to particles with curved surfaces
Hesse, E.; McCall, D.; Ulanowski, Z.; Stopford, C.; Kaye, Paul H. (University of Hertfordshire, 2008)The applicability of RTDF is extended to particles with curved surfaces. This allows tests against T-matrix calculations for larger size parameter and modeling of light scattering by more realistic particle shapes, such ... -
Applying machine learning methods for characterization of hexagonal prisms from their 2D scattering patterns – an investigation using modelled scattering data
Salawu, Emmanuel Oluwatobi; Hesse, Evelyn; Stopford, Chris; Davey, Neil; Sun, Yi (2017-11-01)Better understanding and characterization of cloud particles, whose properties and distributions affect climate and weather, are essential for the understanding of present climate and climate change. Since imaging cloud ... -
Beam tracing with diffraction
Taylor, Laurence; Hesse, Evelyn; Ulanowski, Z.; Kaye, Paul H.; Penttila, Antti; Nousiainen, Timo (2015-06-21) -
Calibration of the cloud and aerosol spectrometer for coal dust composition and morphology
Barone, Teresa; Hesse, Evelyn; Seaman, Clara; Baran, Anthony; Beck, T.W.; Harris, M.L.; Jaques, P.A.; Lee, T.; Mischler, S.E. (2019-09-01)The cloud and aerosol spectrometer (CAS) was calibrated to enable CAS sizing of coal dust for studies on flammable dust control. Coal dust sizes were determined by light-scattering theories for irregular particles that ... -
Characterization of small ice crystals using frequency analysis of azimuthal scattering patterns
Ulanowski, Zbigniew; Stopford, Chris; Hesse, Evelyn; Kaye, Paul H.; Hirst, Edwin; Schnaiter, M. (2007)Azimuthal scattering patterns obtained from ice crystals using the Small Ice Detector 2 are examined. They are converted to frequency spectra using Fast Fourier Transform. To classify the shape of the crystals, the spectra ... -
Characterizing ice particles using two-dimensional reflections of a lidar beam
Goerke, Marissa; Ulanowski, Zbigniew; Ritter, Georg; Hesse, Evelyn; Neely, Ryan; Taylor, Laurence; Stillwell, Robert; Kaye, Paul (2017-07-01)We report a phenomenon manifesting itself as brief flashes of light on the snow surface near a lidar beam. The flashes are imaged and interpreted as specular reflection patterns from individual ice particles. Such patterns ... -
Cirrus clouds
Heymsfield, Andrew J.; Kraemer, Martina; Brown, Philip; Cziczo, Dan; Franklin, Charmaine; Lawson, Paul; Lohmann, Ulrike; Luebke, Anna; McFarquhar, Greg; Ulanowski, Zbigniew; Van Tricht, Kristof (2017)The goal of this article is to synthesize information about what is now known about one of the three main types of clouds, cirrus, and to identify areas where more knowledge is needed. Cirrus clouds, composed of ice ... -
Classifying atmospheric ice crystals by spatial light scattering
Kaye, Paul H.; Hirst, Edwin; Greenaway, Richard; Ulanowski, Zbigniew; Hesse, Evelyn; DeMott, P.; Saunders, C.; Connolly, P. (2008)We describe preliminary results from an optical scattering instrument designed to assess the shapes and sizes of microscopic atmospheric cloud particles, especially the smallest ice crystals, that can profoundly affect ... -
Cloud chamber experiments on the origin of ice crystal complexity in cirrus clouds
Schnaiter, Martin; Järvinen, Emma; Vochezer, Paul; Abdelmonem, Ahmed; Wagner, Robert; Jourdan, Olivier; Mioche, Guillaume; Shcherbakov, Valery N.; Schmitt, Carl G.; Tricoli, Ugo; Ulanowski, Zbigniew; Heymsfield, Andrew J. (2016-04-25)This study reports on the origin of ice crystal complexity and its influence on the angular light scattering properties of cirrus clouds. Cloud simulation experiments were conducted at the AIDA (Aerosol Interactions and ... -
Cloud chamber laboratory investigations into scattering properties of hollow ice particles
Smith, Helen; Connolly, Paul; Baran, Anthony; Hesse, Evelyn; Smedley, Andrew; Webb, Ann (2015-05-01)Measurements are presented of the phase function, P11, and asymmetry parameter, g, of five ice clouds created in a laboratory cloud chamber. At −7 °C, two clouds were created: one comprised entirely of solid columns, and ... -
Cloud characterization using a particle-counter dropsonde
Ulanowski, Zbigniew; Kaye, Paul; Hirst, Edwin; Wieser, Andreas; Stanley, Warren (2015-04-12)Routine meteorological data is obtained in the atmosphere using disposable radiosondes, giving temperature, pressure, humidity and wind speed. Additional measurements are obtained from dropsondes, released from research ... -
Cloud Ice Properties: In Situ Measurement Challenges
Baumgardner, Darrel; Abel, Steve; Axisa, Duncan; Cotton, Richard; Crosier, Jonathan; Field, P.R.; Gurganus, Colin; Heymsfield, Andrew J.; Korolev, Alexei; Kraemer, Martina; Lawson, Paul; McFarquhar, Greg; Ulanowski, Zbigniew; Um, Junshik (2017-04-10)Understanding the formation and evolution of ice in clouds requires detailed information on the size, shape, mass and optical properties of individual cloud hydrometeors and their bulk properties over a broad range of ... -
Difficulties in early ice detection with the Small Ice Detector 2 HIAPER (SID-2H) in maritime cumuli
Johnson, Alexandria; Lasher-Trapp, Sonia; Bensemer, Aaron; Ulanowski, Joseph; Heymsfield, Andrew J. (2014-06)The Small Ice Detector 2 HIAPER (SID-2H) was used to attempt to detect small ice particles in the early stages of ice formation in the high liquid water environment of tropical maritime cumulus clouds sampled during the ... -
Discussion of a physical optics method and its application to absorbing smooth and slightly rough hexagonal prisms
Hesse, Evelyn; Taylor, Laurence; Collier, Christopher T.; Penttila, Antti; Nousiainen, Timo; Ulanowski, Zbigniew (2018-10-01)Three different mathematical solutions of a physical optics model for far field diffraction by an aperture due to Karczewski and Wolf are discussed. Only one of them properly describes diffraction by an aperture and can, ... -
Dust layer profiling using an aerosol dropsonde
Ulanowski, Z.; Kaye, Paul H.; Hirst, Edwin; Wieser, Andreas; Stanley, Warren (2015-04-12)Routine meteorological data is obtained in the atmosphere using disposable radiosondes, giving temperature, pressure, humidity and wind speed. Additional measurements are obtained from dropsondes, released from research ...