An overview of microphysical properties of Arctic clouds observed in May and July 1998 during FIRE ACE

Lawson, R. Paul; Baker, A. B.; Schmitt, Carl; Jensen, Tara

doi:10.1029/2000jd900789

Cited by 314 publications

(301 citation statements)

References 44 publications

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“…The CPI records images of cloud particles with high resolution (2.3 µm) on a 1 million pixel charge coupled device. A 25 ns pulsed high-power laser is triggered when a cloud particle is detected in the sample volume by two lower powered particle detection lasers shining on photodiode detectors (Lawson et al, 2001). Due to the CPI's resolution, only particles larger than about 10 µm are counted.…”

Section: Data Setmentioning

confidence: 99%

Dimensions and aspect ratios of natural ice crystals

McFarquhar

Hong

et al. 2015

Atmos. Chem. Phys.

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Abstract. During the 2006 Tropical Warm Pool InternationalCloud Experiment (TWP-ICE) in the tropics, the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) in the Arctic, and the 2010 Small PARTicles In CirrUS (SPAR-TICUS) campaign at mid-latitudes, high-resolution images of ice crystals were recorded by a Cloud Particle Imager at temperatures (T ) between −87 and 0 • C. The projected maximum dimension (D ), length (L ), and width (W ) of pristine columns, plates, and component bullets of bullet rosettes were measured using newly developed software, the Ice Crystal Ruler. The number of bullets in each bullet rosette was also measured. Column crystals were further distinguished as either horizontally oriented columns or columns with other orientations to eliminate any orientation effect on the measured dimensions. The dimensions and aspect ratios (AR, the dimension of the major axis divided by the dimension of the minor axis) of crystals were determined as functions of temperature, geophysical location, and type of cirrus.Dimensions of crystals generally increased with temperature. Columns and bullets had larger dimensions (i.e., W ) of the minor axis (i.e., a axis) for a given dimension (i.e., D or L ) of the major axis (i.e., c axis), and thus smaller AR, as T increased, whereas this trend did not occur for plate crystals. The average number of branches in bullet rosettes was 5.50 ± 1.35 during three campaigns and 6.32 ± 1.34 (5.46 ± 1.34; 4.95 ± 1.01) during TWP-ICE (SPARTICUS; ISDAC). The AR of bullets increased with the number of branches in bullet rosettes. Most dimensions of crystals and ARs of columnar crystals measured during SPARTICUS were larger than those measured during TWP-ICE and IS-DAC at −67 < T < −35 • C and at −40 < T < −15 • C, respectively. The relative occurrence of varying pristine habits depended strongly on cirrus type (i.e., anvil or non-anvil clouds), with plates especially occurring more frequently in anvils. The L-W relationships of columns derived using current data exhibited a strong dependence on temperature; similar relationships determined in previous studies were within the range of the current data.

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Section: Data Setmentioning

confidence: 99%

Dimensions and aspect ratios of natural ice crystals

McFarquhar

Hong

et al. 2015

Atmos. Chem. Phys.

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“…Several studies on Arctic clouds have already been published describing microphysical and optical properties during projects such as FIRE-ACE (Shupe et al, 2001), SHEBA , and M-PACE (Shupe et al, 2008) and SEARCH (de Boer et al, 2009). For example, extensive in situ observations have been performed in mixed-phase clouds (Hobbs and Rangno, 1998;Lawson et al, 2001;Korolev et al, 2003;McFarquhar and Cober, 2004;McFarquhar et al, 2007) as well as remote sensing observations by Shupe et al (2001), Intrieri et al (2002), Dong and Mace (2003) and Zuidema et al (2005). There have also been a number of modeling studies published in the last year through analysis of a couple of case studies of single-and multi-layer mixed-phase clouds during M-PACE (Morrison et al, 2008;Fridlind et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…This paper focusses on observations obtained from a combination of instruments installed onboard the Polar-2 aircraft operated by the Alfred Wegener Institute for Polar and Marine Research (AWI). These instruments include: a Polar Nephelometer (Gayet et al, 1997), a Cloud Particle Imager (CPI, Lawson et al, 2001) as well as standard Forward Scattering Spectrometer Probe (FSSP-100) to measure cloud particle properties in terms of scattering, morphology and size, and in-cloud partitioning of ice/water content. Remote sensing measurements were obtained onboard the Polar-2 aircraft from the Airborne Mobile Aerosol Lidar (AMALi, Stachlewska et al, 2004) and the Spectral Modular Airborne Radiation measurement sysTem (SMART, Wendisch et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Microphysical and optical properties of Arctic mixed-phase clouds. The 9 April 2007 case study.

Gayet

Mioche

Dörnbrack³

et al. 2009

Atmos. Chem. Phys.

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Abstract. Airborne measurements in Arctic boundarylayer stratocumulus were carried out near Spitsbergen on 9 April 2007 during the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) campaign. A unique set of co-located observations is used to describe the cloud properties, including detailed in situ cloud microphysical and radiation measurements along with airborne and co-located spaceborne remote sensing data (CALIPSO lidar and CloudSat radar). CALIPSO profiles indicate cloud top levels at temperature between −24 • C and −21 • C. In situ measurements confirm that the cloud-top lidar attenuated backscatter signal along the aircraft trajectory is linked with the presence of liquid water, a common feature observed in Arctic mixedphase stratocumulus clouds. A low concentration of large ice crystals is also observed up to the cloud top resulting in significant CloudSat radar echoes. Since the ratio of the extinction of liquid water droplets to ice crystals is high, broadband radiative effects near the cloud top are mostly dominated by water droplets. CloudSat observations and in situ measurements reveal high reflectivity factors (up to 15 dBZ) and precipitation rates (1 mm h −1 ). This feature results from efficient ice growth processes. About 25% of the theoretically available liquid water is converted into ice water with large precipitating ice crystals. Using an estimate of mean cloud cover, a considerable value of 10 6 m 3 h −1 of fresh water could be settled over the Greenland sea pool. European Centre for Medium-Range Weather Forecast (ECMWF) operational analyses reproduces the boundary layer height variation along the flight track. However, small-scale featuresCorrespondence to: J.-F. Gayet (gayet@opgc.univ-bpclermont.fr) in the observed cloud field cannot be resolved by ECMWF analysis. Furthermore, ECMWF's diagnostic partitioning of the condensed water into ice and liquid reveals serious shortcomings for Arctic mixed-phased clouds. Too much ice is modelled.

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“…For example, the modeling approach to retrieve ice particle parameters used by Shcherbakov et al (2006a,b) assumed crystals to be hexagonal columns/plates. The airborne polar nephelometer (PN) by Gayet et al (2001) measures the scattering function of the ice particles and was used in conjunction with results from an imaging probe (CPI) (Lawson et al, 2001) to investigate the impact of the ice crystal habits on the radiative properties of cirrus clouds. This could be done only in a statistical approach with assumptions made regarding the particle shape within an ensemble of randomly oriented particles.…”

Section: Introductionmentioning

confidence: 99%

First correlated measurements of the shape and light scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS) probe

et al. 2011

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Abstract. Studying the radiative impact of cirrus clouds requires knowledge of the relationship between their microphysics and the single scattering properties of cloud particles. Usually, this relationship is obtained by modeling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. We present here a novel optical sensor (the Particle Habit Imaging and Polar Scattering probe, PHIPS) designed to measure simultaneously the 3-D morphology and the corresponding optical and microphysical parameters of individual cloud particles. Clouds containing particles ranging from a few micrometers to about 800 µm diameter in size can be characterized systematically with an optical resolution power of 2 µm and polar scattering resolution of 1 • for forward scattering directions (from 1 • to 10 • ) and 8 • for side and backscattering directions (from 18 • to 170 • ). The maximum acquisition rates for scattering phase functions and images are 262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice cloud campaigns conducted in the AIDA cloud simulation chamber are presented. PHIPS showed reliability in operation and produced size distributions and images comparable to those given by other certified cloud particles instruments. A 3-D model of a hexagonal ice plate is constructed and the corresponding scattering phase function is compared to that Correspondence to: A. Abdelmonem (ahmed.abdelmonem@kit.edu) modeled using the Ray Tracing with Diffraction on Facets (RTDF) program. PHIPS is a highly promising novel airborne optical sensor for studying the radiative impact of cirrus clouds and correlating the particle habit-scattering properties which will serve as a reference for other single, or multi-independent, measurement instruments.

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An overview of microphysical properties of Arctic clouds observed in May and July 1998 during FIRE ACE

Cited by 314 publications

References 44 publications

Dimensions and aspect ratios of natural ice crystals

Dimensions and aspect ratios of natural ice crystals

Microphysical and optical properties of Arctic mixed-phase clouds. The 9 April 2007 case study.

First correlated measurements of the shape and light scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS) probe

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