Arctic Mixed-Phase Clouds: Observations and Modeling Challenges - - PowerPoint PPT Presentation

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Arctic Mixed-Phase Clouds: Observations and Modeling Challenges Gijs de Boer (1) Edwin W. Eloranta (I), Matthew D. Shupe (2), Taneil Uttal (2), Jennifer Kay (3), Tempei Hashino (1), Gregory J. Tripoli (1) (1) (2) ESRL (3) CCSM Polar

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SLIDE 1

Arctic Mixed-Phase Clouds: Observations and Modeling Challenges

Gijs de Boer (1) Edwin W. Eloranta (I), Matthew D. Shupe (2), Taneil Uttal (2), Jennifer Kay (3), Tempei Hashino (1), Gregory J. Tripoli (1)

(1) (2) (3)

ESRL

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

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SLIDE 2

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Low-Level Mixed-Phase Clouds

Time (UT) Altitude (km) Lidar backscatter cross section (Masked values shown in black and white) 12:05 12:10 12:15 12:20 12:25 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 1/(m str) 1e!8 1e!7 1e!6 1e!5 1e!4 1e!3

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SLIDE 3

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Radiative Influence

  • Low altitude stratus frequency of up to 70% during

transition seasons (Herman and Goody, 1976; Curry et al., 1996)

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SLIDE 4

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Radiative Influence

  • Low altitude stratus frequency of up to 70% during

transition seasons (Herman and Goody, 1976; Curry et al., 1996)

  • Reduces wintertime net surface cooling by 40-50

Wm-2 (Curry et al., 1996)

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SLIDE 5

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Radiative Influence

  • Low altitude stratus frequency of up to 70% during

transition seasons (Herman and Goody, 1976; Curry et al., 1996)

  • Reduces wintertime net surface cooling by 40-50

Wm-2 (Curry et al., 1996)

  • Commonly observed during several recent Arctic

experiments (SHEBA, MPACE, SEARCH, ISDAC)

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SLIDE 6

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Radiative Influence

  • Low altitude stratus frequency of up to 70% during

transition seasons (Herman and Goody, 1976; Curry et al., 1996)

  • Reduces wintertime net surface cooling by 40-50

Wm-2 (Curry et al., 1996)

  • Commonly observed during several recent Arctic

experiments (SHEBA, MPACE, SEARCH, ISDAC)

  • Often long-lived, surviving up to several days at a time

(de Boer et al., 2008,2009a)

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SLIDE 7

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Mixed-Phase Clouds and Sea Ice

  • Kay et al. (2008) link anomalous decreases in cloud

cover and associated increases in downwelling shortwave radiation to record breaking 2007 sea ice extent minimum.

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SLIDE 8

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Mixed-Phase Clouds and Sea Ice

  • Kay et al. (2008) link anomalous decreases in cloud

cover and associated increases in downwelling shortwave radiation to record breaking 2007 sea ice extent minimum.

  • Schweiger et al. (2008) relate longwave flux anomalies

caused by changes in local meteorology to the 2007 sea ice minimum, and determined that increased shortwave effects due to reduced clouds did not play a significant role.

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SLIDE 9

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Mixed-Phase Clouds and Sea Ice

  • Kay et al. (2008) link anomalous decreases in cloud

cover and associated increases in downwelling shortwave radiation to record breaking 2007 sea ice extent minimum.

  • Schweiger et al. (2008) relate longwave flux anomalies

caused by changes in local meteorology to the 2007 sea ice minimum, and determined that increased shortwave effects due to reduced clouds did not play a significant role.

  • What about sea-ice effects on clouds?
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SLIDE 10

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Mixed-Phase Clouds and Sea Ice

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SLIDE 11

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Formation Mechanisms

Barrow Oliktok Point

(Klein et al., 2009, modified)

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SLIDE 12

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Formation Mechanisms

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Surface Subsaturated T=T0 Radiative Cooling to Space

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SLIDE 13

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Formation Mechanisms

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Surface Subsaturated T=T0 Radiative Cooling to Space Surface Saturated+ T<T0

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SLIDE 14

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Simulation

F

  • r

P e e r R e v i e w

liquid water path (g m-2) ice water path (g m-2)

171

(Klein et al., 2009)

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SLIDE 15

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Simulation

2 4 6 8 10 0.2 0.4 0.6 Time (hrs) Altitude (km) sim #1::Cloud Water Mixing Ratio (g/kg) 0.02 0.04 0.06 0.08 0.1 2 4 6 8 10 0.2 0.4 0.6 Time (hrs) Altitude (km) sim #1::Snow Mixing Ratio (g/kg) 0.01 0.02

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SLIDE 16

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Observations

D N A L N E E R G A D A N A C D E T I N U S E T A T S

Eureka Barrow

BEAUFORT SEA

80 N 70 N NP

Barrow: 09/04-11/04 Eureka: 08/05-present High Spectral Resolution Lidar MMCR (35 GHz) Radiosondes

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SLIDE 17

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Observations

Time (UT) ) m k ( e d u t i t l A 13 14 15 16 17 18 19 20 21 22 23 1.0 2.0 3.0 4.0 Time (UT) ) m k ( e d u t i t l A 13 14 15 16 17 18 19 20 21 22 23 1.0 2.0 3.0 4.0

  • Single-layer

mixed phase stratus

  • bservations
  • 216 hours

from Barrow (fall 2004)

  • 1240 hours

from Eureka (fall 2005-2007)

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SLIDE 18

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Temperatures

245 250 255 260 265 270 275 280 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 Cloud Top Temperature (K) LWF

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SLIDE 19

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Temperatures

245 250 255 260 265 270 275 280 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 Cloud Top Temperature (K) LWF

Linear phase partition between -10 and -40 C (standard SCAM)

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SLIDE 20

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Macrophysical Properties

696 m (Barrow) 1670 m (Eureka) 674 m (Barrow) 331 m (Eureka)

2000 4000 6000 Zbase (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007 400 800 1200 1600 Cld Thickness (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

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SLIDE 21

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Macrophysical Properties

696 m (Barrow) 1670 m (Eureka) 674 m (Barrow) 331 m (Eureka)

2000 4000 6000 Zbase (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007 400 800 1200 1600 Cld Thickness (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

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SLIDE 22

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Macrophysical Properties

696 m (Barrow) 1670 m (Eureka) 674 m (Barrow) 331 m (Eureka)

2000 4000 6000 Zbase (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007 400 800 1200 1600 Cld Thickness (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

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SLIDE 23

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Macrophysical Properties

696 m (Barrow) 1670 m (Eureka) 674 m (Barrow) 331 m (Eureka)

2000 4000 6000 Zbase (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007 400 800 1200 1600 Cld Thickness (m) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

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SLIDE 24

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Macrophysical Properties

Barrow Eureka

(Images courtesy of Jennifer Kay)

From A-Train

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SLIDE 25

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Ice Formation

  • Primary Ice Formation (Pruppacher and Klett, 1997)
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SLIDE 26

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Ice Formation

  • Primary Ice Formation (Pruppacher and Klett, 1997)
  • Condensation nucleation
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SLIDE 27

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Ice Formation

  • Primary Ice Formation (Pruppacher and Klett, 1997)

(Contact)

  • Nucleation through free IN
  • Condensation nucleation
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SLIDE 28

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Ice Formation

  • Primary Ice Formation

(Deposition)

(Pruppacher and Klett, 1997)

(Contact)

  • Nucleation through free IN
  • Condensation nucleation
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SLIDE 29

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Ice Formation

  • Primary Ice Formation

(Deposition)

(Pruppacher and Klett, 1997)

(Contact)

  • Nucleation through free IN

฀฀฀ ฀฀฀ ฀

  • Immersion nucleation
  • Condensation nucleation
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SLIDE 30

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Ice Formation

  • Secondary Ice Formation
  • Multiplication mechanisms
  • Drop shattering:
  • Ice-Ice Collisions:
  • Splinter ejection during riming (Hallett-Mossop, 1974)
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SLIDE 31

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Temperatures

240 250 260 270 Temperature (K) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

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SLIDE 32

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Temperatures

240 250 260 270 Temperature (K) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

Splinter Ejection (> -8°C)(Heymsfield and Mossop, 1984)

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SLIDE 33

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Temperatures

240 250 260 270 Temperature (K) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

Splinter Ejection (> -8°C)(Heymsfield and Mossop, 1984) Homogeneous Freezing (< -35°C)(Hagen et al., 1981; Jensen et al., 1998)

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SLIDE 34

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Vertical Motion

(Shupe et al., 2008)

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SLIDE 35

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Vertical Motion

(Shupe et al., 2008)

slide-36
SLIDE 36

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Ice Formation

Aerosols:

  • Bigg (1980) observed sulfuric acid coating on

aerosol particles during winter

  • Sulfuric coating is water soluble, transforming

possible IN into CCN.

  • Sulfate is primarily produced through the
  • xidation of SO2 in clouds, through reactions with

peroxides or ozone (Kreidenweis et al., 2003). SO2 is produced in the oxidation of dimethylsulfide (DMS) (along with sulfuric acid (H2SO4) and methanesulfonic acid (MSA)). The MSA and H2SO4 are transformed to the particle phase through condensation on pre-existing biogenic particles. (Gabric, 2005; Leck et al., 2002). SO2 also has anthropogenic sources.

From in-situ measurements:

  • Ice crystal concentrations strongly proportional

to concentration of drops larger than 20 µm. (Rangno & Hobbs, 2001)

Observational Clues

Bigg (1980)

slide-37
SLIDE 37

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Immersion Freezing

฀฀฀ ฀฀฀ ฀

slide-38
SLIDE 38

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Immersion Freezing

Conceptual Model for Mixed-Phase Stratus

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Initialization

slide-39
SLIDE 39

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Immersion Freezing

Conceptual Model for Mixed-Phase Stratus

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀

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฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

Initialization

slide-40
SLIDE 40

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Immersion Freezing

Conceptual Model for Mixed-Phase Stratus

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀

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฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀

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Mature

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฀

  • ฀
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฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

Initialization

slide-41
SLIDE 41

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Immersion Freezing

Conceptual Model for Mixed-Phase Stratus

฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

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฀฀฀ ฀฀฀ ฀

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Mature

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฀

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฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀ ฀฀฀ ฀฀฀ ฀

Initialization

slide-42
SLIDE 42

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Simulation Challenges

(Image from Paul DeMott)

slide-43
SLIDE 43

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Simulation Challenges

  • Ice nucleation schemes based on CFDC data...

7.84 7.86 7.88 7.9 7.92 7.94 7.96 x 10

4

10

!2

10

!1

10 10

1

10

2

10

3

10

4

time (s) Concentration (#/L) Ice Particles Ice Nuclei

slide-44
SLIDE 44

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Simulation Challenges

  • Ice nucleation schemes based on CFDC data...
slide-45
SLIDE 45

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Summary

  • Low-level, mixed-phase stratiform clouds are common in

the Arctic

  • Feedback mechanisms between regulating interactions

between these clouds and sea ice are not yet well understood

  • Models have a difficult time representing mixed-phase

microphysics, in part due to uncertainties in ice nucleation

  • Observations provide clues to help solve nucleation

mystery, and immersion freezing may play active role in ice nucleation

  • There appears to be a fundamental disconnect between
  • bservations and simulation of ice nucleation
slide-46
SLIDE 46

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

References

Curry, J.A., W.B. Rossow, D. Randall, and J.J. Schramm (1996), Overview of Arctic cloud and radiation characteristics, J. Climate, 9, 1731-1764. de Boer, G., E.W. Eloranta, and M.D. Shupe (2009), Arctic mixed-phase stratiform cloud properties from multiple years of surface-based measurements at two high-latitude locations, Submitted to JAS.

  • ----, T. Hashino and G. J. Tripoli (2009), A theory for ice nucleation through immersion freezing in mixed-

phase stratiform clouds, Submitted to Atmos. Res..

  • ----, de Boer, G., G. J. Tripoli and E. W. Eloranta (2008), Preliminary comparison of cloudsat-derived microphysical

quantities with ground-based measurements for mixed-phase cloud research in the arctic, J.

  • Geophys. Res., 113.

Garbric, A,J., B. Qu, P . Matrai and A.C. Hirst (2005), The Simulated Response of Dimethylsulfide Production in the Arctic Ocean to Global Warming. Tellus, 57B, 391-403. Herman, G. and R. Goody (1976), Formation and persistence of summertime Arctic clouds, J. Atmos. Sci., 33, 1537-1553. Heymsfield, A.J., and S.C. Mossop (1984), Temperature dependence of secondary ice crystal production during soft hail growth by riming, Quart. J. Roy. Meteor. Soc., 110, 765-770. Jensen, E.J., and Coauthors (1998), Ice nucleating processes in upper tropospheric wave-clouds observed during SUCCESS, Geophys. Res. Lett., 25, 1363-1366. Kay, J.E., T. L’Ecuyer, A. Gettelman, G. Stephens and C. O’Dell (2008), The contribution of cloud and radiation anomalies to the 2007 Arctic sea ice extent minimum, Geophys. Res. Lett., 35, L08503, doi: 10.1029/2008GL033451. Klein, S.A., and co-authors (2009), Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single-layer cloud, Submitted to QJRMS. Kreidenweis, S.M., and co-authors (2003), Modification of Aerosol Mass and Size Distribution Due to Aqueous- Phase SO2 Oxidation in Clouds: Comparison of Several Models. J. Geophys. Res., 108, 4213. Leck, C., M. Norman and E.K. Bigg (2002), Chemical Composition and Sources of the High Arctic Aerosol Relevant for Cloud Formation, J. Geophys. Res., 107, 4135. Schweiger, A.J., J. Zhang, R.W. Lindsay and M. Steele (2008), Did unusually sunny skies help drive the record sea ice minimum of 2007?, Geophys. Res. Lett., 35, L10503, doi:10.1029/2008GL033463. Shupe, M.D., P . Kollias, P .O.G. Persson, and G.M. McFarquhar (2008), Vertical motions in Arctic mixed-phase stratiform clouds, J. Atmos. Sci., 65, 1304-1322.

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SLIDE 47

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

EXTRA SLIDES | | | V

slide-48
SLIDE 48

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Macrophysical Properties

EUREKA

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SLIDE 49

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Cloud Frequency

26% (Barrow) 8% (Eureka)

10 20 30 Frequency (%) SON A SON DJF MAM JJA SON DJF MAM JJA SON D 2004 2005 2006 2007

532 70 435 370 160 103 468 191 61 278 281 61

slide-50
SLIDE 50

CCSM Polar Working Group Meeting, Santa Fe, NM 19-20 February, 2009

Immersion Freezing

mole L-1

r

N,c =

ac

3 A − sv,wac

( )

A + B − sv,w

( )ac

     

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