1NASA Ames Research Center
Natural pollution events and their role in ice cloud formationMichal Segal-Rosenheimer, Patrick Hamill, S. Ramachandran
ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
OR: What can we learn from such events on the interaction between aerosol and
ice clouds?
2NASA Ames Research Center
Introduction
ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Potential effects: We know that increased IN concentration can cause mixed-phase
clouds glaciation [e.g.; Seifert et al., 2011, JGR; Choi et al., 2010, PNAS], formation of
new ice clouds [Sassen and Khvorostyanov 2008, Environ.Res.Let.] or a change of existing
ice clouds microphysical properties (COT and Deff) [e.g. Storelvmo et al., 2013, JGR]
Volcanic Dust Biomass burning
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Dust, Ash , Soot are efficient IN, and have a wide range of Temperature and supersaturation “activation” values [Hoose and Möhler,2012]
What do we know?
Ground-based Lidar observations showed mixed-phase clouds glaciation [e.g. Seifert et al., 2011], and ice formation [e.g. Sassen and Khvorostyanov 2008]
Global models (ECHAM; Hendricks et al., 2011 and CAM5; Liu et al., 2012]show that heterogeneous ice nucleation leads to fewer but larger crystals
In-situ in-cloud sampling that measure IN amount under ambient conditions [e.g. DeMott et al., 2003] and residual chemical composition are used toderive model parameterizations for ice heterogeneous nucleation schemes.
These IN are responsible for ice formation via Heterogeneous nucleation
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What do we still need to know?
ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
While models can resolve concentrations, and ice properties in 3-D on a global scale; they only have sparse in-situ observations at specific locations to compare to [e.g. Hoose et al., 2010; Liu et al., 2012].Various parameterization schemes predict different amounts of ice concentrations and relative effects of heterogeneous versus homogeneous nucleation [Liu et al., 2012] and show that results are very sensitive to parameterization assumptions [Hendricks et al., 2011] and aerosol characterizationWe still need better constraints on heterogeneous
nucleationdescribed in models
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How to bridge the gap?
ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
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Objectives and approach
ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
To test whether heavy-aerosol events can serve as an “outdoor laboratory” that can improve our understanding on the connection between specific aerosol types and ice clouds incidence and their microphysical properties
1. To use heavy aerosol events – better spatial and temporal constrain to research domain.2. To use spectral analysis, together with microphysical and state parameters from IR sounders to link aerosol-ice3. Support observations with trajectory and dispersion/ chemical transformation analysis to constrain observed trends in ice cloud properties and amount that can be compared with specific model simulations.
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
How does Heavy-Aerosol Events Affect Ice Cloud
Formation?
The Eyjafjallajokull 2010 Eruption
case study
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Constraining the case study domain – using Forward trajectory & literature [e.g. Petersen, 2010, Weather; Seifert et al., 2011, JGR]
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Case study domain cloud related property distributions from AIRS – Eruption period
200 500 8000
0.01
0.02
Clo
ud
To
p P
an
om
ally
200 500 8000
0.01
0.02
200 500 8000
0.01
0.02
200 500 8000
0.01
0.02
200 250 3000
0.01
0.02
0.03
Clo
ud
To
p T
an
om
ally
200 250 3000
0.01
0.02
0.03
200 250 3000
0.01
0.02
0.03
200 250 3000
0.01
0.02
0.03
0 40 80 1200
0.005
0.01
O
LR
an
om
ally
0 40 80 1200
0.005
0.01
0 40 80 1200
0.005
0.01
0 40 80 1200
0.005
0.01
0 0.5 10
0.01
0.02
Clo
ud
fra
ctio
nC
F a
no
mal
ly
2010-04-1-140 0.5 1
0
0.01
0.02
2010-04-14-200 0.5 1
0
0.01
0.02
2010-04-21-280 0.5 1
0
0.01
0.02
2010-04-29-05-05
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
(a1) BTD pair values representative of ash from April 17th (granule 133, 13:20UT), and the corresponding (a2) MODIS-Aqua true color image granule (downloaded from EOSDIS Rapid Response website), which shows the ash plumes. Other panels (b-e) show zoomed-in areas for various pixels in (a), and their BT spectra (marked with different symbols) on the right of each row that further demonstrate the variety of spectral slopes for ice. Panels (f) show classification maps Symbols are the same as upper panels, and correspond to same BT spectra as above (for example, the diamond symbol was classified as ice containing ash).BTD relationships and thresholds are based on literature values (e.g. Francis et al., 2012;Clarisse et al. 2010, Gangale et al., 2010)And on local clear region thresholds.
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Ice clouds Cloud Top Temperature bins
220 230 240 250 260 2700
20
40
60
80
100
(% ic
e)
Cloud Top Temperature [K]
Ice and Ash cloudy pixels (n=3347)
Ice only (n =274352)
Cloud top temperatures for the inherent AIRS FOV (15x15km) are taken from the Dual Regression (DR) algorithm package [Smith et al., 2012]
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Cloud top Temperature distributions for each group
200 210 220 230 240 250 260 2700
5
10
15
Cloud top Temperature [K]
% Ic
e/Ic
e+
As
h c
lou
ds
re
lati
ve
to
to
tal c
lou
ds
Ice only (n =274352)
Ice and Ash cloudy pixels (n=3347)
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Cloud phase fraction over the whole domain – April 10-20 2010SEVIRI (PATMOS-x retrieval L2B cloud product)
Day of Year
No
rmal
ized
fre
qu
ency
[-]
101 102 103 104 105 106 107 108 109 110 1110
0.2
0.4
0.6
0.8
1
1.2
1.4watersupercooledice
Ice/
sup
erco
ole
d (
frac
tio
n)
0.8
1
1.2
1.4
1.6
1.8
2
Major eruption period
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
2-D distribution functions of Cloud Top Temp versus Cloud Height
0 5 10 15
210
220
230
240
250
260
270
280
Cloud Height [km]
2010101
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
Cloud Height [km]
2010102
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
Cloud Height [km]
2010103
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010104
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010105
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010106
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010107
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010108
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010109
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010110
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
0 5 10 15
210
220
230
240
250
260
270
280
2010111
Cloud Height [km]
Clo
ud
To
p T
emp
[k]
0
0.02
0.04
0.06
0.08
0.1
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
2-D distribution functions of Cloud Top Temp versus Cloud Height
0 5 10 15
210
220
230
240
250
260
270
280
Cloud Height [km]
2010111
C
lou
d T
op
Tem
p [
k]0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
0 5 10 15
210
220
230
240
250
260
270
280
Cloud Height [km]
2010101
Clo
ud
To
p T
emp
[k]
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
a
b
c
a
b
c
Eruption Period
200 210 220 230 240 250 260 270 2800
2
4all ice
(%)
200 210 220 230 240 250 260 270 2800
0.5
1ice < 6km
(%)
200 210 220 230 240 250 260 270 2800
20
40ice > 6km
(%)
Cloud Top Temperature [K]
2010-04-11 (pre-eruption)
2010-04-20 (post-eruption)
18NASA Ames Research Center
ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Eruption Period
200 210 220 230 240 250 260 270 2800
2
4all ice
(%)
200 210 220 230 240 250 260 270 2800
0.5
1ice < 6km
(%)
200 210 220 230 240 250 260 270 2800
20
40ice > 6km
(%)
Cloud Top Temperature [K]
2010-04-11 (pre-eruption)
2010-04-21 (post-eruption)
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Baseline Period
a
b
c
200 210 220 230 240 250 260 270 2800
2
4all ice
(%)
200 210 220 230 240 250 260 270 2800
0.5
1ice < 6km
(%)
200 210 220 230 240 250 260 270 2800
20
40ice > 6km
(%)
Cloud Top Temperature [K]
2012-04-10
2012-04-20
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Eruption Period
225 230 235 240 245 250 255 260 265 2700
50
100all ice
(% i
ce)
225 230 235 240 245 250 255 260 265 2700
50
100ice < 6km
(% i
ce)
225 230 235 240 245 250 255 260 265 2700
50
100ice > 6km
(% i
ce)
Cloud Top Temperature [K]
2010-04-11 (pre-eruption)
2010-04-20 (post-eruption)
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Baseline Period
a
b
c
225 230 235 240 245 250 255 260 265 2700
50
100all ice
(% i
ce)
225 230 235 240 245 250 255 260 265 2700
50
100ice < 6km
(% i
ce)
225 230 235 240 245 250 255 260 265 2700
50
100ice > 6km
(% i
ce)
Cloud Top Temperature [K]
2012-04-10
2012-04-20
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
2-D distribution functions of Reff versus ice COT
Ice COT
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
2-D distribution functions of Reff versus ice COT
0 2 4 6 8
20
40
60
80
100
120
140
160
ice COT
2010111 low ice (< 6km)
Re
ff [ m
]
0
0.005
0.01
0.015
0.02
0.025
0.03
0 2 4 6 8
20
40
60
80
100
120
140
160
ice COT
2010111 high ice (> 6km)
Re
ff [ m
]
0
0.005
0.01
0.015
0.02
0.025
0.03
0 2 4 6 8
20
40
60
80
100
120
140
160
ice COT
2010101 low ice (< 6km)
Re
ff [ m
]
0
0.005
0.01
0.015
0.02
0.025
0.03
0 2 4 6 8
20
40
60
80
100
120
140
160
ice COT
2010101 high ice (> 6km)
Ref
f [ m
]
0
0.005
0.01
0.015
0.02
0.025
0.03
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Eruption Period
0 20 40 60 80 100 120 140 1600
10
20
30all ice
(%)
0 20 40 60 80 100 120 140 1600
10
20
30ice < 6km
(%)
0 20 40 60 80 100 120 140 1600
10
20
30ice > 6km
(%)
Reff
[m]
2010-04-11 (pre-eruption)
2010-04-20 (post-eruption)
a
b
c
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Baseline Period
0 20 40 60 80 100 120 140 1600
10
20
30all ice
(%)
0 20 40 60 80 100 120 140 1600
10
20
30ice < 6km
(%)
0 20 40 60 80 100 120 140 1600
10
20
30ice > 6km
(%)
Reff
[m]
2012-04-10
2012-04-20
a
b
c
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
April 20, 2010, 4 days back-trajectory
Ice cloud heights (4-6km)
210 215 220 225 230 235 240 245 2500
10
20
30
40
50
60
70
80
90
100
(%)
Cloud Top Temperature [K]
2010-04-20 Ash effected ice region
2010-04-20 Clean ice region
-140 -120 -100 -80 -60 -40 -20 0 20 40 6040
45
50
55
60
65
70
75
80
85
90
LongitudeoE
Lat
itu
de
oN
Region A - back-trajectory (5 km)
Region A - back-trajectory (6 km)Region B - back-trajectory (5 km)
Region B - back-trajectory (6 km)
A
B
A
B
0 20 40 60 80 100 120 140 1600
5
10
15
20
25
30
(%)
Reff
[m]
2010-04-20 Ash effected ice region
2010-04-20 Clean ice region
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
210 215 220 225 230 235 240 245 2500
10
20
30
40
50
60
70
80
90
100
(%)
Cloud Top Temperature [K]
2010-04-20 Ash effected ice region
2010-04-20 Clean ice region
Ice cloud heights (6-10km)
April 20, 2010, 4 days back-trajectory
-140 -120 -100 -80 -60 -40 -20 0 20 40 6020
30
40
50
60
70
80
90
LongitudeoE
Lat
itu
de
oN
Region A - back-trajectory (7 km)
Region A - back-trajectory (9 km)Region B - back-trajectory (7 km)
Region B - back-trajectory (9 km)
A
B
AB
0 20 40 60 80 100 120 140 1600
5
10
15
20
25
30
(%)
Reff
[m]
2010-04-20 Ash effected ice region
2010-04-20 Clean ice region
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Specific case studies, when compared with simulations can aid in the decision of whether parameterization will be sufficient for the whole chemical group (e.g. dust) or whether it needs to be fine-tuned in the models for each region
Case study results cover large regional areas, which are more proper to compare withRegional/global model simulations
Int. Summary (work in progress…)It seem that heavy aerosol events can serve as a test-bed to identify cloud microphysics
changes and processes via regional investigation such as the one demonstrated
We have observed cloud formation in temperatures higher than the ones observed forCleaner regions and baseline periods and between clear/polluted regions
We see an increase in ice cloud amount (both relative to super-cooled phase and high clouds) relative to baseline periods
We have observed Reff values increasing in mid-level clouds when comparing pre-eruption to post-eruption and baseline periods
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
Interact with global modeling groups (GEOS-Chem/CAM5) to investigate the specificCase studies and improve model parameterization (Pending proposal)
Next steps (work in progress…)Create 2-D or higher dimensional PDF of cloud microphysical properties for several
Pre-selected case studies designed to look at Ash, dust and Biomass-burning events.
Combine aerosol fields vertical distributions using back-trajectory analysis and globalAerosol models (RAQMS/GOCART) to link properties to specific aerosol types
Combine extracted cloud microphysical properties with aerosol properties derivedEither from satellite products for Ash-Dust (IR hyperspectral sounders or CALIPSO)And for biomass-burning (MODIS or CALIPSO)
Perform ice microphysical box modeling along back trajectories from cloud topsTo better assess the conditions needed to form clean/polluted ice in case study regions
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ISSCP at 30 : What Do We Know and What Do We Still Need to Know?
© Michal Segal
Acknowledgements:Andrew Heidinger and Mike Foster – Geostationary cloud products
NASA Postdoctoral Program (NPP/ORAU)Weizmann Institute of Science, Israel