1. WCRP polar climate predictability initiative Vladimir Ryabinin www.wcrp-climate.org

2. Bergen workshop (October 2010): science-driven – Informal WCRP Report A notable gap was that between scientific communities, as most people knew only a small minority of the other participants. …it seems apparent that progress in polar predictability will require crossing disciplinary boundaries to understand the feedbacks between the troposphere and the stratosphere, ocean, land, and sea ice

3. (Douville, 2009) (SST)

4. Seasonal Forecast from AER (Atmospheric & Environmental Research) (J. Cohen, 2011) Predictability: seasonal Role of snow cover

5. Snow Forced Signal J. Cohen, 20…

6. J. Overland Multiple feedbacks involving sea ice

7. J. Overland -- > Warm AO – cold continents

8. A. Hall

10. Role of Sea Ice Y. Orsolini

11. Annual mean Arctic sea ice area anomalies and oceanic volume flux (upper 125 m) through Spitzbergen- Norway meridional (about 20E) cross-section (Bengtsson, 2004) Correlation between wintertime Arctic sea ice area and SATs Predictability: inter-annual Barents inflow Barents Sea Cyclonic circulation Westerly winds r = - 0.77

12. (Ed Hawkins) (Boer & Lambert) Predictability: decadal Decadal: forced change + natural variability

13. J. Boer

14. Coordinated Regional Downscaling Experiment – CORDEX IPCC AR5 Climate-system Historical Forecast Project - CHFP Coupled Model Intercomparison Experiment 5 – CMIP5 IPCC AR5 Chemistry-Climate Model Validation Climate Predictions and Projections sea ice, stratosphere Arctic Antarctic Africa

15. The nature of feedbacks appears to be different in the two hemispheres leading to different big questions: – Understanding and predicting the rate of Arctic sea ice loss – Understanding the drivers of change in the Antarctic, including connections to ozone, ocean circulation, carbon uptake, and ice shelves Imperatives – Improve models – Identify measurement needs, both for initialization and for monitoring variability and long-term changes

16. IASC Atmosphere meeting in Denver (October 23, 2011) – IASC-A sees itself as more bottom up, e.g. field experiments, and sees the WCRP initiative as being very complementary (link through Jim Overland, NOAA PMEL) Toronto workshop (April 2-4, 2012) – Aim for around 30-35 people, representing science topics and partner activities (some continuity with Bergen) – Outcome will be a draft implementation plan to be considered at the JSC meeting in July 2012

17. Expected implementation mechanisms – Targeted workshops – Climate process teams – Coordinated evaluation/assessment of data sets Observational data sets Reanalyses Seasonal predictions (CHFP) Historical simulations (CMIP) Decadal and longer timescale predictions (CMIP) – OSSEs to define measurement needs – Coordinated model experiments

18. WCRP Grand Challenges Provision of skillful future climate information on regional scales (includes decadal and polar predictability) Regional Sea-Level Rise Cryosphere response to climate change (including ice sheets, water resources, permafrost and carbon) Improved understanding of the interactions of clouds, aerosols, precipitation, and radiation and their contributions to climate sensitivity Past and future changes in water availability (with connections to water security and hydrological cycle) Science underpinning the prediction and attribution of extreme events

19. Models, a lot of similarities Observations, almost enough for NWP, not the case for climate Data assimilation: melt ponds, land surface, stratosphere, more for climate Goal: seamless multi-scale prediction system Different readiness to address prediction needs in NH and SH Polar regions are only the focus of targeted improvements within our projects but the overall progress in prediction will be achieved by global systems -> need a reliable and welcoming entry of our results into global systems – roles of WWRP & WCRP Same communities? How big is the overlap? Welcome to Toronto… WCRP polar climate predictability initiative & WWRP Polar Prediction Research Project: commons