Arctic CloudsArctic CloudsSergey MatrosovJanet IntrieriMatthew ShupeTaneil UttalShelby FrischEd WestwaterYong HanChris FairallOla PerssonCold Regions Research LabUniversity of WashingtonUniversity of ColoradoEnvironmental Services Canada

Why is the Arctic important?

• Coupled climate models show the largestdisagreements in the polar regions

• CO2 warming may be strongly amplified byretreat and thinning of sea ice

• The North Atlantic thermohalinecirculation exerts important controls onclimate variability on scales ranging fromyears to millennia

From “Status of and Outlook for Large Scale Modeling of Atmosphere-Ice-OceanInteractions in the Arctic” – Randall et al., 1998, BAMS, 197-219

Why are Arctic Clouds Important?

• Strong cloud-radiation feedbacks

• Clouds-radiation feedbacks are linked tosnow/ice-albedo feedbacks

• The Arctic atmosphere is very cloudy

From Overview of Arctic Cloud and Radiation CharacteristicsCurry et al., 1996, Journal of Climate, pp 1731-1764

Why are Arctic Clouds Hard?Polar Night Low contrast between clouds

and snow ice

Simultaneous Liquid and Ice Clouds

Temperature/humidity inversions

Sparsely Inhabited

SAFIRESHEBA

DOE/ARM/NSAFIRE – ACE

Instruments

Combining Information From Instruments Operatingat Different Wave Lengths

Radar Reflectivity

Radar DopplerVelocities

RadiometricLiquid Water Path

LidarDepolarization

Ratios

LidarBackscatter

RawinsondeTemperature and Humidity Profiles

Radar/LidarRatios - 1993

A Suite of Cloud Microphysical Retrieval Techniques(Matrosov, Frisch, Intrieri)

IR Brightness TemperaturesAnd MW water vapor path

Layer MeanValues - 1992

Vertical Profiles1994

Vertical Profiles1995

Tuned Vertical Profiles - 1999

Inputs Ice Retrievals Liquid retrievals

Vertical Profiles Regression - 2000

Vertical ProfilesRegression -2000

Vertical ProfilesRadar Only - 2000

18 hour ice cloud case observed on April 28-29 1998 during SHEBA – Results

Subjective selection from the suite oftechniques to produce daily retrievals

Cloud Classification

Retrievals From Barrow, AKJune 20th, 2000

Validation with Aircraft Measurements

36 Flights Over the SHEBA Ice CampDuring April – July, 1998

Problem Identification with AircraftMeasurements

19.3 (6.7)17.3 (3.5)90.7All Months

15.0 (5.9)23.2 (5.6)93.9July

23.4 (7.9)18.4 (4.5)87.8June

17.6 (6.1)23.2 (3.8)88.0May

21.3 (7.0) 4.2 (0.0)93.1April

All-ice

(and single layer)

All-liquid

(and single layer)

FractionalCloudiness

Cloudiness Statistics during April-July 1998 atSHEBA

0.007

g/m3

0.005

g/m3

0.001

g/m3

0-0.1

g/m3

Ice WaterContent

75µm

60µm

46µm

7-300µm

MeanDiameter(ice)

0.08

g/m3

0.1

g/m3

0.06

g/m3

0-0.7

g/m3

LiquidWaterContent

6.2µm

7.4µm

6.9µm

3-20µm

Effective

Radius

(liquid)

Mean

(flight days)

MeanMedianRange

Retrieval Statistics during April-July, 1998 at SHEBA

Retrieved Vertical Profiles

Monthly Fraction of Cloud Occurrence

Monthly Fraction of Clouds with Liquid Phaseand Fraction of Clouds which attenuate the lidar

Comparison of Echo Boundary Detection withRadar and Lidar

Cloud Forcing over the Arctic Ocean

Total Cloud Forcing Over Arctic Ocean

Research in Publication Phase• An Annual Cycle of Cloud Characteristics Observed by

Radar and Lidar at SHEBA (Intrieri, Uttal, Shupe,McCarty)

• Cloud Water Contents and Hydrometeor Sizes During theFIRE-Arctic Clouds Experiment (Shupe, Uttal, Matrosov,Frisch)

• Annual Cycle of Cloud Forcing Observed at SHEBA(Intrieri, Fairall, Shupe and Persson)

• Airborne Studies of Cloud Structures over the Arctic Oceanand Comparison with Retrievals from Ship-Based RemoteSensing Measurements (Hobbs, Rango, Shupe, Uttal)

• Cloud Coverage and Height During FIRE-ACE Derivedfrom AVHRR DATA (Minnis and others)

SEARCHStudy of Environmental Arctic ChangeNational Oceanic and Atmospheric Administration

National Aeronautics and Space AdministrationU.S. Environmental Protection Agency

National Science FoundationU.S. Department of DefenseU.S. Department of Energy

Cloud Bow Over the SHEBA Ice Camp onJuly 15th, 1998