PHIPS–HALO: the airborne Particle Habit Imaging and Polar
Scattering probe – Part 1: Design and operation

Abdelmonem, Ahmed; Järvinen, Emma; Duft, Denis; Hirst, Edwin; Vogt, Steffen; Leisner, Thomas; Schnaiter, M.

doi:10.5194/amt-9-3131-2016

Cited by 45 publications

(50 citation statements)

References 32 publications

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“…Since the liquid water content that freezes does not vary with updraft strength, the freezing of more numerous droplets in the faster updrafts simply produces smaller ice particles. This is clearly shown by Ackerman et al (2015), in which ice particle mass distributions in homogeneous freezing for stronger updrafts produce substantially smaller ice particles. Schnaiter et al (2016) further showed that high ice particle growth rates also enhance the formation of small-scale complexity, such as ice particle surface roughness.…”

Section: The Cloud Chambermentioning

confidence: 80%

“…Wendisch and Brenguier (2013) compiled a comprehensive list covering 48 different instruments, many of which are historical, but recently there have been several new developments, e.g. Abdelmonem et al (2016) and Baumgardner et al (2014Baumgardner et al ( , 2017. Many of the current techniques, however, are technological improvements on previous instruments originally developed and flown in the 1970s.…”

Section: Introductionmentioning

confidence: 99%

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Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment

Nichman¹,

Järvinen²,

Dorsey³

et al. 2016

Preprint

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Abstract. Optical probes are frequently used for the detection of microphysical cloud particle properties such as liquid and ice phase, size and morphology. These properties can eventually influence the angular light scattering properties of cirrus clouds as well as the growth and accretion mechanisms of single cloud particles. In this study we compare four commonly used optical probes to examine their response to small cloud particles of different phase and asphericity. Cloud simulation experiments were conducted at the Cosmics-Leaving-OUtdoor-Droplets (CLOUD) chamber at European Organisation for Nuclear Research (CERN). The chamber was operated in a series of multi-step adiabatic expansions to produce growth and sublimation of ice particles at super- and sub-saturated ice conditions and for initial temperatures of −30, −40 and −50 °C. The experiments were performed for ice cloud formation via homogeneous ice nucleation. We report the microphysical properties of small quasi-spherical ice particles in deep convection simulations and small hexagonal ice particles typical for in situ cirrus. Ice crystal asphericity and a degree of submicron complexity deduced from measurements of spatially resolved single particle light scattering patterns by the Particle Phase Discriminator mark 2 (PPD-2K, Karlsruhe edition) were compared with Cloud and Aerosol Spectrometer with Polarisation (CASPOL) measurements and images captured by the 3View Cloud Particle Imager (3V-CPI). Averaged path light scattering properties of the simulated ice clouds were measured using the Scattering-Intensity-Measurements-for-the-Optical-detectioN-of-icE (SIMONE) and single particle scattering properties were measured by the CASPOL. We show the ambiguity of several optical measurements in ice fraction determination of homogeneously frozen ice, in the case where sublimating quasi-spherical ice particles are present. Moreover, most of the instruments have shown a rather low sensitivity to the crystal complexity for small ice cloud particles that were grown under typical atmospheric conditions. Bulk averaged path depolarisation measurements of these clouds showed higher correlation to single particle measurements at high concentration and small diameters of cloud particles. These results have implications for the interpretation of atmospheric measurements and parametrisations for modelling, particularly for low particle number concentration clouds. This ensemble of optical instruments, using both averaged path and single particle detection presented here, in conjugation with the CLOUD chamber, reveals the possible discrepancies in comparisons of airborne and remote sensing measurements.

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Section: The Cloud Chambermentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment

Nichman¹,

Järvinen²,

Dorsey³

et al. 2016

Preprint

Self Cite

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show abstract

“…The Particle Habit Imaging and Polar Scattering probe (Abdelmonem et al, 2016) data were used to discriminate ice particles and droplets based on angular light scattering measurements (Schnaiter et al, 2018). The appearance of liquid droplets in clouds was defined when the LWC is greater than 0.005 g m −3 in a previous study by Baumgardner and Rodi (1989).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Cloud Microphysical Properties Derived From MODIS and Himawari‐8 Using In Situ Aircraft Measurements Over the Southern Ocean

Zhao

Wang

et al. 2020

Earth and Space Science

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Cloud microphysical properties from aircraft measurements during the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study are used to evaluate the cloud products from the geostationary satellite Himawari-8 (H-8) and the polar-orbiting satellite the Moderate Resolution Imaging Spectroradiometer (MODIS). Compared to the in situ aircraft observations when aircraft flew horizontally near cloud tops, the cloud droplet effective radius (r e ) and number concentration (N d ) from H-8 (MODIS) are 33% (26%-31%) and 2% (9-13%) larger. Both the H-8 and MODIS retrievals behave similarly for liquid-only and mixed-phase low-level clouds, indicating the weak sensitivity of the satellite cloud retrieval performance to cloud phase. The r e and N d of the cloud profiles from aircraft measurements were also used to compare with the satellite product. It shows that H-8 r e and N d agree better with aircraft measurements when considering only the in situ data acquired in the upper portions (highest 20%) of the clouds. Roughly, the r e overestimation by H-8 decreases from 18% to 3% when considering the upper portions of clouds compared to all cloud layer averages, except for one case with drizzles appeared. In addition, the performance of MODIS r e and N d is highly dependent on the wavelengths the retrieval method uses. The droplet r e retrievals using wavelength of 1.6 μm have much larger biases than that using the other two channels. The potential effects of the cloud vertical variation and the photon penetration depth, the cloud heterogeneity, the cloud droplet size spectra, and the drizzle on satellite retrievals have also been discussed. is a co-corresponding author with Chuanfeng Zhao Key Points:• Himawari-8 (MODIS) cloud product overestimates r e near cloud top by 33% (26-31%) over Southern Ocean • Himawari8 r e and N d agree better with aircraft measurements when considering only the in situ data acquired in the upper portions of clouds • The performance of MODIS retrievals depends on the wavelength, with larger biases at 1.6 μm than 2.1 and 3.7 μm

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“…(e.g. Macke et al, 1996;Yang and Liou, 1998;Baran et al, 2001; Baran and Francis, 2004;Sun et al, 2004;Yang et al, 2008;Baum et al, 2010;Platnick et al, 2017). Later, it was found that ice crystal parameterizations implementing roughened surfaces represent the measured optical properties, especially the polarization effects of atmospheric ice clouds, more accurately than parameterizations based on a mixture of pristine ice crystals (Baran and Labonnote, 2006;Um and McFarquhar, 2007;Jourdan et al, 2010;Liu et al, 2014b;Yi et al, 2016;Tang et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Authors’ Response to Interactive Comment by Z Ulanowski

Järvinen¹

2018

Preprint

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Ice crystal submicron structures have a large impact on the optical properties of cirrus clouds and consequently on their radiative effect. Although there is growing evidence that atmospheric ice crystals are rarely pristine, direct in situ observations of the degree of ice crystal complexity are largely missing. Here we show a comprehensive in situ data set of ice crystal complexity coupled with measurements of the cloud angular scattering functions collected during a number of observational airborne campaigns at diverse geographical locations. Our results demonstrate that an overwhelming fraction (between 61 % and 81 %) of atmospheric ice crystals sampled in the different regions contain mesoscopic deformations and, as a consequence, a similar flat and featureless angular scattering function is observed. A comparison between the measurements and a database of optical particle properties showed that severely roughened hexagonal aggregates optimally represent the measurements in the observed angular range. Based on this optical model, a new parameterization of the cloud bulk asymmetry factor was introduced and its effects were tested in a global climate model. The modelling results suggest that, due to ice crystal complexity, ice-containing clouds can induce an additional shortwave cooling effect of − 1.12 W m 2 on the top-of-theatmosphere radiative budget that has not yet been considered.

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PHIPS–HALO: the airborne Particle Habit Imaging and Polar Scattering probe – Part 1: Design and operation

Cited by 45 publications

References 32 publications

Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment

Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment

Evaluation of Cloud Microphysical Properties Derived From MODIS and Himawari‐8 Using In Situ Aircraft Measurements Over the Southern Ocean

Authors’ Response to Interactive Comment by Z Ulanowski

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