Keith M. Hines 1 and David H. Bromwich 1,2 1 Polar Meteorology Group, Byrd Polar Research Center, Ohio State University, Columbus, OH, USA 2 Department of Geography, Ohio State University, Columbus, OH, USA Free Atmosphere Processes

Outline Clouds 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 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 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 doesnt increase cloud cover.

What we do (dont) know about Antarctic clouds David H. Bromwich 1, Julien P. Nicolas 1 and Jennifer E. Kay 2 International Workshop on Antarctic Clouds Columbus, July Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, OH 2 National Center for Atmospheric Research, Boulder, CO

Introduction Why knowledge of Antarctic is important Antarctic radiative budget 1. Clouds reflect solar energy 2. Clouds absorb long-wave radiation emitted from the surface Over high-albedo surfaces, the short-wave flux absorbed at the surface is already small: effect 2 > effect 1 Impact on Antarctic surface mass balance Role 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) 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 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 [Spinhirne et al., 2005]

Active vs passive cloud remote sensing Cloud frequency over Antarctica in Oct from GLAS, MODIS and ISCCP [Hart et al., 2006] Cloud frequency from GLAS and HIRS (NOAA-14) from Oct. 1-Nov [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 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 layers How do mixed-phase Arctic clouds appear? Ice near base 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 of Arctic 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 Interactions Most studies of cloud-aerosol interactions have focused on warm clouds Most studies of cloud-aerosol interactions have focused on warm clouds Cloud-aerosol interactions more complex for ice or mixed-phase clouds Cloud-aerosol interactions more complex for ice or mixed-phase clouds Glaciated & mixed-phase clouds common in Arctic Still unclear why they persist for so long Aerosols have strong seasonal cycle in Arctic to examine indirect effects Two DOE-ARM field experiments at different times (fall 2004/spring 2008) provide contrast to study mixed-phase clouds & aerosol effects Two DOE-ARM field experiments at different times (fall 2004/spring 2008) provide contrast to study mixed-phase clouds & aerosol effects

M-PACE Science Questions 1. How are liquid & ice spatially/temporally partitioned, and how are ice crystals partitioned with size? 2. What is impact of partitioning on radiative transfer and fall-out? 3. How can in-situ observations be used to improve radar/lidar retrievals? 4. Why do mixed-phase clouds persist? 5. How can we better represent mixed-phase clouds in 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 Oct

M-PACE October 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. ISDAC April 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