In-situ Observations of Ice Crystal Habits, Their Crystal...

KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

1Kalrsruhe Institute of Technology, 2Johannes Gutenberg-Universität , 3Max Planck Institute for Chemistry, 4Deutsches Zentrum für Luft-und Raumfahrt, 5Ludwig-Maximilians-Universität, 6University of Leipzig

www.kit.edu

In-situ Observations of Ice Crystal Habits, Their Crystal Complexity and Light Scattering Properties During ACRIDICON-CHUVAACRIDICON-CHUVA Workshop, Ilhabela

Emma Järvinen1, C. Mahnke2, M.O. Andreae3, H. Schlager4, R. Weigel2, B. Weinzierl5, M. Wendisch6, and M. Schnaiter1

Karlsruhe Institute of Technology (KIT)

Institute for Meteorology and Climate Research (IMK-

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Ice crystal complexity

10.03.2016 Emma Järvinen – ACRIDICON-CHUVA Workshop, Ilhabela

Large-scale

complexity

Small-scale

complexity

Ulanowski et al., ACP, 2014Connolly et al. (2005)



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Scattering phase function of ice particles depend on their shape and

complexity (aggregation, polycrystals, surface roughness, hollowness, etc.)

Polycrystal and roughened ice particles show a featurless scattering

function

20.06.2014

Scattering angle (°)

P. Yang et al., JAS, 2013

A. J. Baran, JQSRT, 2009

Complex particles – similar light scattering

Emma Järvinen – ACRIDICON-CHUVA Workshop, Ilhabela



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Ice Crystal Complexity Increases Back Reflection

Lab and modeling

studies show that

roughness reduces the

asymmetry parameter

2 times higher back

reflection

20.06.2014

Ulanowski et al., JQSRT, 2006




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PHIPS / SID-3 Package on-board HALO

HALO (High Altitude and Long Range Research

Aircraft)

10.03.2016

PHIPS-

HALO

SID-3




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PHIPS/SID-3 Instrument Package

10.03.2016

PHIPS-HALO

Polar light scattering function (1° to 170°) of single ice particles

Simultaneous stereoscopic (3D) imaging of the same particle

Large-scale complexity (50 µm – 1 mm)

SID-3

Spatial light scattering (diffraction) pattern in forward direction (6° to 25°)

Shape information especially for small particles (5 - 50 µm)

Small-scale complexity

100 µm




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Large-Scale Complexity

10.03.2016

Schmitt & Heymsfield (2014)PHIPS-HALO

single crystals

aggregates




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Small-scale Ice Crystal Complexity

10.03.2016

Crystal complexity leads to spatially

randomized light scattering. The shape

distinct diffraction features will

disappear.

Pristine column

Roughened or distorted column




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Quantification of Small-scale Complexity

through ke

04.03.2015

Discu

ssion

Pap

er|

Discu

ssion

Pap

er|

Discu

ssion

Pap

er|

Discu

ssion

Pap

er|

Figure A1.

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σ ~ ke

σ: 0

ke: 4.05

Schnaiter et al., ACPD, 2015

4.11

0.10.05

4.09

Pristine Complex




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Ice Crystal Habits




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Particle Habit Classification: in-situ vs outflow

10.03.2016

In-situ cirrus Outflow cirrus




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10.03.2016

Outflow cirrus

Connolly et al. (2015)




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10.03.2016

In-situ cirrusLawson et al. (2006)

Connolly et al. (2005)




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Ice particles imaged with PHIPS-HALO instrument were classified to

plates, columns, bullet rosettes, small ice particles and (plate)

aggregates




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Large-scale complexity




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Flight Overview

Outflow anvils were probed at different altitudes and some anvils with

different distances to the core

10.03.2016

Flight Aerosol

concentration

AC11 490 cm-3

AC15 1100 cm-3

AC16 2000 cm-3

AC20 2000 cm-3

Outflow flights

In-situ cirrus

AC12




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Outflow Southwest of Manaus

10.03.2016

Photo by courtesy of Manfred Wendisch

Figure by Ramon Braga




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10.03.2016

Photo by courtesy of Manfred Wendisch

216 K 200 μm




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10.03.2016

Outflow well mixed up to the upper edge




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CRYSTAL-FACE AC20

SID-3


Single habits

Aggregates

Dimensions of the Complex Particles



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10.03.2016

AC12

AC16

AC15

AC20

Single habits Single habits

Single habitsSingle habits

Aggregates

Aggregates

Aggregates



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Large-Scale Complexity

10.03.2016

CRYSTAL-FACE ACRIDICON-CHUVA

SID-3




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The Liquid Origin of Outflow Ice Particles

10.03.2016

Plates formed at temperatures above -40°C

Riming observed

AC20 rimed plates




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Small-scale complexity




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Flight Overview

Outflow anvils were probed at different altitudes and some anvils with

different distances to the core

10.03.2016

Flight Aerosol

concentration

AC11 490 cm-3

AC15 1100 cm-3

AC16 2000 cm-3

AC20 2000 cm-3

Outflow flights

In-situ cirrus

AC12




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10.03.2016

Photo by courtesy of Hans Schlager

100 μm"100 μm"




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Outflow North of Manaus

10.03.2016

Photo by courtesy of Hans Schlager

100 μm"100 μm"

220 K




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A" B"

Outflow North of Manaus

10.03.2016

A"

B"

Z. Ulanowski, ICCP, 2004

PHIPS Images of Frozen Droplets

20 μm

SID3 Diffraction Patterns




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Ice Crystal Complexity

10.03.2016

AC12 in-situ cirrus

Fraction of complex

particles: 0.74

AC11 “clean” outflow

Fraction of complex

particles: 0.82

AC20 polluted

outflow

Fraction of complex

particles: 0.67




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PHIPS-HALO

SID-3 Complex




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Take-Home Message

Verified a method to study large-scale complexity from PHIPS-HALO

images

Outflows well mixed

High degree of crystal complexity is observed in all sizes, shapes and

formation pathways

This leads to uniform angular light scattering behaviour


In-situ Observations of Ice Crystal Habits, Their Crystal...

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