Keith M. Hines1 and David H. Bromwich1,2

1Polar Meteorology Group, Byrd Polar Research Center, Ohio State University, Columbus, OH, USA

2Department of Geography, Ohio State University, Columbus, OH, USA

Free Atmosphere Processes

Free Atmosphere Processes

OutlineClouds in the Arctic and

Antarctic

• Clouds in Arctic mesoscale simulations• Clouds in the Antarctic region• Clouds and aerosols in the Arctic• Summary

• Clouds in Arctic mesoscale simulations• Clouds in the Antarctic region• Clouds and aerosols in the Arctic• Summary

Polar WRF Test – Phase III: Arctic Land• Polar WRF with WRF version 3.0.1.1

• Western Arctic Grid 141 x 111 points, 25 km spacing, 28 levels

• Atmospheric Initial and Boundary Conditions: GFS FNL

• Sea Ice Fraction: NSIDC/WIST AMSR-E (25 km)

• Soil Initial and Boundary Conditions

Fixed Temperature at 8 m depth from Drew Slater

bottom of the phase change boundary temperature

Initial Soil Temperature and Soil Moisture from Mike Barlage

10-year Noah Arctic run for spin-up driven by JRA-25

start set for 0000 UTC 15 November 2006

• Run for November 2006 to July 2007

48-hour Simulations with GFS Atmospheric I.C.

Cycle Soil Temperature, Soil Moisture, Skin Temperature

48-hr output Day X run I.C. for Day X+2 run Runs on OSC Glenn Cluster

Sensitivity Tests: change PBL, change microphysics, add soil moisture

Results: The PBL and microphysics impact the Arctic stratus over the Arctic Ocean, but little impact over land at Atqasuk.

Added soil moisture doesn’t increase cloud cover.

What we do (don’t) know about Antarctic clouds

David H. Bromwich1, Julien P. Nicolas1 and Jennifer E. Kay2

International Workshop on Antarctic CloudsInternational Workshop on Antarctic CloudsColumbus, 14-15 July 2010Columbus, 14-15 July 2010

1Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, OH

2 National Center for Atmospheric Research, Boulder, CO

IntroductionWhy knowledge of Antarctic is important

Antarctic radiative budget1. Clouds reflect solar energy2. Clouds absorb long-wave radiation emitted from the

surfaceOver high-albedo surfaces, the short-wave flux absorbed

at the surface is already small: effect 2 > effect 1

Impact on Antarctic surface mass balanceRole of stratospheric clouds in ozone depletion

• Polar stratospheric clouds support chemical reactions conducive to the destruction of stratospheric ozone

Observing Antarctic clouds

Ground-based measurements

• Dedicated effort to study and measure Antarctic clouds• South Pole Atmospheric Radiation and Cloud LIDAR

Experiment (SPARCLE) 1999-2001• Instruments:

• Polar Atmospheric Emitted Radiance Interferometer (PAERI)• Tethered Balloon System • Micropulse Lidar• South Pole Transmissometer

• Results:• Climatology of clouds (e.g., M. Town)• Cloud microphysics (e.g., V. P. Valden)

Active remote sensing: Lidar

• Lidar measurements onboard an LC-130 flown between McM and South-Pole, Jan. 1986

• Multilayering of clouds

• Ice crystals trails from high-elevated cirrus observed to “seed” the mid-level clouds

Morley et al., 1989

McM

SP

Active remote sensing: Lidar

• Ex.: Geoscience Laser Altimeter System (GLAS) on ICESat

Backscatter cross-section from GLAS over Antarctica at 15:00 UTC, 1 Oct. 2003

[Spinhirne et al., 2005]

Active vs passive cloud remote sensing Cloud frequency over Antarctica in Oct. 2003from GLAS, MODIS and ISCCP [Hart et al., 2006]

Cloud frequencyfrom GLAS and HIRS

(NOAA-14) fromOct. 1-Nov. 16 2003

[Wylie et al. 2007]

More about cloud satellite remote sensing with Dan Lubin

Cloud microphysics

• Measurements with the PAERI allow for the retrieval of cloud microphys. properties

• Figure: relative occurrence of different cloud types in Feb. 2001 at South Pole

[Ellison et al., 2006]

Cloud types at South Pole

Antarctic Cloud Conclusions

• Antarctic cloud studies are in a new era with the spaceborne observations (CloudSat, CALIPSO)

• Validation with recent remote sensing techniques is needed for the full range of Antarctic environments

• The record for these new observations is short and temporal resolution is limited

Greg McFarquhar

University of Illinois

Dept. of Atmospheric Sciences

International Workshop on Antarctic Clouds

Ohio State University, 15 July 2010

Airborne Measurements of Clouds and Aerosols during ISDAC and M-PACE

Response of Clouds• Atmospheric, terrestrial & oceanic changes are occurring

in Arctic• clouds play central role in many feedbacks• interactions between clouds, aerosols, atmosphere &

ocean more complex, have greater climatic impact & less understood than in other locations

Vorosmarty et al. 2001

In multi In multi layerslayers

How do mixed-phase Arctic clouds appear?

Ice near Ice near basebase

In single layer

Liquid near top

Eloranta

Mixed phase clouds occur regularly in the Arctic, especially in the spring & fall

Supercooled water contents large enough that they can

cause aircraft instruments to ice up

Mixed phase clouds occur regularly in the Arctic, especially in the spring & fall

Supercooled water contents large enough that they can

cause aircraft instruments to ice up

Why do these clouds persist?

Mixed phase clouds occur regularly in the Arctic, especially in the spring & fall

Supercooled water contents large enough that they can

cause aircraft instruments to ice up

How do aerosols affect these & other arctic clouds?

Mixed phase clouds occur regularly in the Arctic, especially in the spring & fall

Supercooled water contents large enough that they can

cause aircraft instruments to ice up

How are clouds & associated energy balance changing as Arctic warms & aerosols increase?

Pollution in Polar Regions(ISDAC 19 April 2008, Large Haze Layers)

Motivations Aerosol effects Optical properties Mexico City ISDAC Future research

Layer ofArctic Haze

Arctic Monitoring and Assessment Programme, 2006

Haze can be transported to the arctic (esp. in winter & spring)

Sources for surface haze generally lie within the Arctic front

Layers aloft may have sources further south (if they can survive cross-front processes)

Clouds with low aerosol concentration do not scatter light well (large cloud droplets)

-High aerosol concentrations nucleation small cloud drops and lots of scattering

-Reduced precip. Efficiency means clouds last longer

Aerosol Impacts on Clouds

Arctic Aerosol/Cloud InteractionsMost studies of cloud-aerosol interactions have Most studies of cloud-aerosol interactions have

focused on warm cloudsfocused on warm cloudsCloud-aerosol interactions more complex for ice Cloud-aerosol interactions more complex for ice

or mixed-phase cloudsor mixed-phase cloudsGlaciated & mixed-phase clouds common in ArcticStill unclear why they persist for so longAerosols have strong seasonal cycle in Arctic to

examine indirect effects

Two DOE-ARM field experiments at different Two DOE-ARM field experiments at different times (fall 2004/spring 2008) provide contrast to times (fall 2004/spring 2008) provide contrast to study mixed-phase clouds & aerosol effectsstudy mixed-phase clouds & aerosol effects

M-PACE Science Questions1.1. How are liquid & ice spatially/temporally partitioned, How are liquid & ice spatially/temporally partitioned,

and how are ice crystals partitioned with size?and how are ice crystals partitioned with size?2.2. What is impact of partitioning on radiative transfer What is impact of partitioning on radiative transfer

and fall-out?and fall-out?3.3. How can in-situ observations be used to improve How can in-situ observations be used to improve

radar/lidar retrievals?radar/lidar retrievals?4.4. Why do mixed-phase clouds persist?Why do mixed-phase clouds persist?5.5. How can we better represent mixed-phase clouds in How can we better represent mixed-phase clouds in

models?models?

Motivation: going beyond M-PACE • Wanted similar & better data from ISDAC

• to describe how differences between spring and fall arctic aerosols produce differences in cloud properties & surface energy balance

• to make more comprehensive observations of aerosols and to fill in missing elements of M-PACE cloud observations (small ice)

• to evaluate performance of cloud & climate models, and long-term retrievals of aerosols, clouds, precipitation & radiative heating.

M-PACE: Sept. 27 - Oct. 22 2004

M-PACEOctober 2004

• Pristine Conditions• Open ocean• Few cloud droplets• Ice multiplication• Precipitation

• Measurements by ~10 instruments• aerosol properties• cloud microphysics• atmospheric state.

• Polluted Conditions• Sea Ice• Many cloud droplets• Ice nucleation• Little precipitation

• Measurements by ~40 instruments• aerosol properties• cloud microphysics• radiative energy• atmospheric state.

ISDACApril 2008

Cloud droplet number concentrations appear to be larger on polluted day of 26 Apr. compared to more pristine day of 8 Apr.

Evidence of indirect effect?

Thank you