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Browsing by Author "Light Scattering and Radiative Processes"
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The effective density of small ice particles obtained from in situ aircraft observations of mid-latitude cirrus
Cotton, Richard; Field, P.R.; Ulanowski, Joseph; Kaye, Paul H.; Hirst, Edwin; Greenaway, Richard; Crawford, I.A.; Crosier, J.; Dorsey, James (2013-10)The effective ice-particle density, parametrized through a mass–dimension relation, is widely used in ice microphysical schemes for weather and climate models. In this study, we use aircraft-based observations in mid-latitude ... -
Effects of Surface Roughness with Two Scales on Light Scattering by Hexagonal Ice Crystals Large Compared to the Wavelength: DDA Results
Collier, Christopher T.; Hesse, Evelyn; Taylor, Laurence; Ulanowski, Zbigniew; Penttila, Antti; Nousiainen, Timo (2016-10-01)The effect of ice crystal surface roughness on light scattering by ice crystals which are large compared to the wavelength was studied, in particular changes to the 2D scattering patterns, azimuthally averaged phase ... -
Fake ice and levitation
Ulanowski, Z.; Hesse, E. (2003) -
First correlated measurements of the shape and scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS) probe
Abdelmonem, A.; Schnaiter, M.; Amsler, P.; Hesse, Evelyn; Meyer, J.; Leisner, T. (2011)Studying the radiative impact of cirrus clouds requires the knowledge of thelink between their microphysics and the single scattering properties of thecloud particles. Usually, this link is created by modeling the ... -
Halo ratio from ground based all-sky imaging
Dandini, Paolo; Ulanowski, Zbigniew; Campbell, David; Kaye, Richard (2019-02-28)The halo ratio (HR) is a quantitative measure characterizing the occurrence of the 22 halo peak associated with cirrus. We propose to obtain it from an approximation to the scattering phase function (SPF) derived from ... -
High-sensitivity Stokes spectropolarimetry on cyanobacteria
Martin, Bill; Hesse, E.; Hough, J.H.; Gledhill, T.M. (2016-02-01)We investigate the spectral signatures arising from the optical properties of chlorophyll in linear and circularly polarised scattered light from cyanobacteria. We include Stokes scattering coefficient measurements on two ... -
Ice crystal habits from cloud chamber studies obtained by in-line holographic microscopy related to depolarization measurements
Amsler, P.; Stetzer, O.; Schnaiter, M.; Hesse, E.; Benz, S.; Moehler, O.; Lohmann, U. (2009)We investigate hydrometeor habits at the AIDA chamber with a newly developed in-line holographic microscope HOLographic Imager for Microscopic Objects (HOLIMO). Sizes and habits of ice crystals and droplets in a mixed-phase ... -
Improved understanding of the vertical distribution of simulated dust distribution in the Saharan Air Layer during the ICE-D field campaign with the WRF-CHEM model
Chiao, Sen; Jenkins, Gregory; Ulanowski, Zbigniew; Smith, Helen (2016-01-11)During the period of 4-27 August of 2015, the UK Ice in dust clouds experiment will take place in Cape Verde. UK_ICE-D will characterize aerosol particles and their ability to act as ice nuclei (IN) and cloud condensation ... -
In-situ observations of volcanic ash clouds from the FAAM aircraft during the eruption of Eyjafjallajökull in 2010
Johnson, Ben; Turnbull, Kate; Brown, Phil; Burgess, Rachel; Dorsey, James; Baran, Anthony J.; Webster, Helen; Haywood, Jim; Cotton, Richard; Ulanowski, Zbigniew; Hesse, Evelyn; Wolley, Alan; Rosenberg, Philip (2012)During April–May 2010 the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft flew 12 flights targeting volcanic ash clouds around the UK. The aircraft observed ash layers between altitudes of 2–8 km ... -
Incidence of rough and irregular atmospheric ice particles from Small Ice Detector 3 measurements
Ulanowski, Joseph; Kaye, Paul H.; Hirst, Edwin; Greenaway, Richard; Cotton, Richard J.; Hesse, Evelyn; Collier, Christopher T. (2014-02-12)The knowledge of properties of ice crystals such as size, shape, concavity and roughness is critical in the context of radiative properties of ice and mixed-phase clouds. Limitations of current cloud probes to measure these ... -
Incidence of rough and irregular atmospheric ice particles from Small Ice Detector 3 measurements
Ulanowski, Zbigniew; Kaye, Paul H.; Hirst, Edwin; Greenaway, Richard; Cotton, Richard J.; Hesse, Evelyn; Collier, Christopher T. (2013)The knowledge of properties of ice crystals such as size, shape, concavity and roughness is critical in the context of radiative properties of ice and mixed phase clouds. Limitations of current cloud probes to measure these ... -
Initial investigation into using Fourier spectra as a means of classifying ice crystal shapes
Stopford, C.; Ulanowski, Z.; Hesse, E.; Kaye, Paul H.; Hirst, E.; Schnaiter, M.; McCall, D. (University of Hertfordshire, 2008)Fast Fourier Transforms of azimuthal light scattering patterns are investigated as a method for classifying cirrus cloud ice crystals. Small Ice Detector Mk. 2 data is compared to modelled reference data of various aspect ... -
Introducing phase tracing into a computational method which combines ray-tracing with diffraction on facets
Hesse, Evelyn; Ulanowski, Zbigniew; Clarke, A.J.M.; Havemann, S.; Kaye, Paul H. (University of Bremen, 2005)The viability of introducing phase tracing into our ray tracing with diffraction on facets model is investigated. In order to prove the method, Monte Carlo ray-tracing results for a slit, based on our diffraction formula ... -
Investigation by surface enhanced Raman spectroscopy of the effect of oxygen or hydrogen plasmas on the surface chemistry of adsorbate-covered gold island films
Hesse, E.; Creighton, J.A. (1999)The effects of radio-frequency-excited oxygen and hydrogen plasmas on gold island films with adsorbed CN-, thiophenate, or p-nitrobenzoate ions have been investigated by surface-enhanced Raman spectroscopy (SERS). An oxygen ... -
Investigation into Single Scattering Properties of Airborne Saharan Dust Particles
McCall, D.; Ulanowski, Z.; Hesse, E.; Stopford, C.; Kandler, K.; Kaye, Paul H. (2008)The phase functions of single mineral dust particles levitated in an electrodynamic balance have been measured. Normalized phase functions and the asymmetry parameter could be determined because nearly the full range of ... -
Investigation of cyanide ions adsorbed on platinum and palladium coated silver island films by surface-enhanced Raman spectroscopy
Hesse, E.; Creighton, J.A. (1999)Bimetallic films prepared by vacuum-depositing platinum onto silver island films have been evaluated for surface-enhanced Raman scattering (SERS), using CN− as the adsorbate. For platinum overlayers with mean thickness ... -
Light scattering by complex ice-analogue crystals
Ulanowski, Zbigniew; Hesse, Evelyn; Kaye, Paul H.; Baran, A.J. (2006)Angle-dependent light scattering measurements on single ice analogues crystals are described. Phase functions and degree of linear polarization are measured for electrodynamically levitated crystals. A procedure for ... -
Light scattering by Gaussian rough ice crystals : experimental and modelling results
Collier, Christopher Thomas; Hesse, Evelyn; Ulanowski, Joseph; Penttila, Antti; Nousiainen, Timo; Brousseau, Emmanuel (2013-06-17)It is qualitatively well understood that ice and mixed-phase clouds have an important role in the radiation balance and climate of the Earth [1,2]. However, quantitative understanding of these clouds is poor, and is one ... -
A light scattering instrument for investigating cloud ice microcrystal morphology
Kaye, Paul H.; Hirst, E.; Ulanowski, Z.; Hesse, E.; Greenaway, R.; DeMott, P. (2008)We describe 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 processes and radiative ... -
A Light Scattering Model for Large Particles with Surface Roughness
Ballington, Harry; Hesse, Evelyn (2024-09)A physical-optics hybrid method designed for the computation of single-scattering properties of particles with complex shapes, including surface roughness, is presented. The method applies geometric optics using a novel ...