1. Greg McFarquhar University of Illinois, Urbana, IL, USA Greg McFarquhar University of Illinois, Urbana, IL, USA Workshop on Clouds, Aerosols, Radiation and Air-Sea Interface of Southern Ocean: Establishing Directions for Future Research, 18-19 March 2014, Seattle, WA Workshop on Clouds, Aerosols, Radiation and Air-Sea Interface of Southern Ocean: Establishing Directions for Future Research, 18-19 March 2014, Seattle, WA Introduction and Goals of Workshop, and Relationship to SOCRATES proposal

2. Chris Bretherton, University of Washington, Seattle, WA Christian Jakob, Monash University, Melbourne, VIC Roj Marchand, University of Washington, Seattle, WA Greg McFarquhar, University of Illinois, Urbana, IL Alain Protat, Australian Bureau of Meteorology, Melbourne, Steven Siems, Monash University, Melbourne, VIC Bob Weller, Woods Hole, Woods Hole, MA Rob Wood, University of Washington, Seattle, WA Chris Bretherton, University of Washington, Seattle, WA Christian Jakob, Monash University, Melbourne, VIC Roj Marchand, University of Washington, Seattle, WA Greg McFarquhar, University of Illinois, Urbana, IL Alain Protat, Australian Bureau of Meteorology, Melbourne, Steven Siems, Monash University, Melbourne, VIC Bob Weller, Woods Hole, Woods Hole, MA Rob Wood, University of Washington, Seattle, WA Steering Committee

3. Workshop Goals 1.Identify state of knowledge of clouds, aerosols & air-sea interaction over Southern Ocean 2.Identify strategies for reducing uncertainties in their representation in global and regional models 3.Ultimate goal: better determining the role of clouds, aerosols & air-sea interaction in climate system.

4. Workshop Deliverable Steering committee expects to develop a whitepaper “Southern Ocean challenges and objectives” that will detail 1.Main challenges about Southern Oceans 2.General science objectives for Southern Oceans 3.More specific science questions 4.Strategy for addressing science questions Strategy for addressing objectives will likely include a field experiment, SOCRATES, as well as satellite analysis & model simulations

6. Why the Southern Ocean? Southern Ocean plays critical role in global climate system & is unique pristine environment But, there have been sparse observations of clouds, aerosols, radiation & air-sea interface in this region. Consequently, much unknown about atmospheric and oceanographic processes and their linkage in this region.

7. Challenges of Southern Ocean 1.Large SW radiation & SST biases in GCMs 2.Contribution of pre-industrial aerosols to indirect forcing 3.Why mixed-phase clouds frequently occur 4.Why is there seasonal cycle in N cloud 5.Influence of sea spray on cloud formation 6.Influence of DMS on aerosols/clouds 7.Why observed mid-level clouds not produced in GCMs 8.Understanding of frontal cloud systems in SO 9.Evaluation of satellite products over SO

8. General Objectives i.Characterize properties of cloud systems over SO, & processes involved in life cycles of cold fronts ii.Characterize aerosol microphysical & chemical properties (including DMS), their role in regulating CCN, and impact on cloud formation/maintenance iii.Evaluate satellite cloud, aerosol, precipitation and ocean products iv.Evaluate/improve skill of models at multiple scales for reproducing aerosol/cloud/radiation/ precipitation interactions Rob Wood’s talk will go into more detail

9. SOCRATES (Southern Ocean Cloud Rain/Radiation, Aerosol Transport Experimental Study We ultimately hope to conduct a field campaign over Southern Oceans Possible proposals to come out of this meeting: – EOD/SOD to NSF for use of G-V/C-130? – Proposal to deploy ARM Mobile Facility? – Proposal to use NASA Global Hawk/ER-2 as high- altitude facility? – Proposal to use Australian R/V Investigator? – Others?

11. Organization of Workshop Tuesday: Review past modeling & observational research efforts in the Southern Ocean region Tuesday AM: Overview talks on the Southern Ocean Tuesday PM: Concurrent sessions on Clouds and Meteorology, and on Aerosols and their interactions with Clouds

12. Organization of Workshop Wednesday: Prioritize remaining scientific issues to be resolved & identify strategy for addressing key aerosol-cloud-climate questions. Wednesday AM: Breakout #1: Formulate key questions on role of aerosols/clouds/air‐sea interactions in Southern Oceans Wednesday PM: Breakout #2: What are needed measurements/retrievals/simulations needed to address hypotheses?

13. General Info We will divide into 3 breakout groups on Wednesday: division/organization of groups discussed Wednesday morning Provide session moderator with copy of slides – Let us know if you do NOT wish them displayed on website Summaries of all breakout sessions will be presented in plenary

14. Acknowledgments Special thanks to Department of Energy Atmospheric Systems and Research Program (DOE ASR) for providing funding to partially support this workshop