1. Regional Arctic Climate System Model (RACM) – Project Overview Participants: Wieslaw Maslowski(PI)- Naval Postgraduate School John Cassano (co-PI)- University of Colorado William Gutowski (co-PI)- Iowa State University Dennis Lettenmeier (co-PI)- University of Washington Greg Newby, Andrew Roberts,- Arctic Region Supercomputing Center / Juanxiang He, Anton Kulchitsky International Arctic Research Center Dave Bromwich (OSU), Gabriele Jost (HPCMO), Tony Craig (NCAR), Jaromir Jakacki, Robert Osinski (IOPAN), Mark Seefeldt (CU), Chenmei Zhu (UW), Justin Glisan, Brandon Fisel (ISU), Jaclyn Kinney (NPS) A 4-year (2007-2011) DOE / SciDAC-CCPP project Arctic System Modeling Workshop, Montreal, Canada, July 16-17, 2009

2. Need for Regional Arctic Climate System Model There are large errors in global climate system model simulations of the Arctic climate system Observed rapid changes in Arctic climate system – Sea ice decline – Greenland ice sheet – Temperature Arctic change has global consequences – Sea ice change can alter the global energy balance and thermohaline circulation

3. "A linear increase in heat in the Arctic Ocean will result in a non-linear, and accelerating, loss of sea ice.“ Norbert Untersteiner, Prof. Emeritus, Univ. of Washington, July 2006 Observed Rate of Loss Faster Than GCM Predicted Adapted from Stroeve et al., 2007

4. GCM Comparison: September 2002 Regions: 1 – Greenland Shelf 2 – Eastern Arctic 3 – Western Arctic NSIDC ice extent 1 2 3 1 2 3 1 2 3 1 2 3 - Too much ice in the western Arctic and over Siberian shelves through 2007 - Too little ice in the eastern Arctic through 2007

5. MIROC CCSM3HadGEM1GFDL-CM2 Selected IPPC-AR4 model September sea ice results

6. Ocean: Heat Transport ObservationsNAME: POP/CICECCSM Fram Strait (Inflow) 7.0 Sv / 50 TW6.9 Sv / 45 TW2.0 Sv / 17 TW FJL – NZ (Net) NA / Near zero2.6 Sv / 2.2 TW4.35 Sv / 31 TW 25 yr mean volume transport (Sv) / Heat Transport ‘NPS’ TRANSPORTS (Maslowski et al., JGR, 2004) Fram Strait ‘in’ obs estimates - Courtesy of A. Beszczynska-Möller, AWI FJL-NZ - (Gammelsrod et al., JMS 2008)

7. Our rationale for developing a regional Arctic climate System Model (ASM) 1.Facilitate focused regional studies of the Arctic 2.Resolve critical details of land elevation, coastline and ocean bottom bathymetry 3.Improve representation of local physical processes & feedbacks (e.g. forcing & deformation of sea ice) 4.Minimize uncertainties and improve predictions of climate change in the pan-Arctic region

8. Specific Goals develop a state-of-the-art Regional Arctic Climate system Model (RACM) including high-resolution atmosphere, ocean, sea ice, and land hydrology components perform multi-decadal numerical experiments using high performance computers to understand feedbacks, minimize uncertainties, and fundamentally improve predictions of climate change in the pan-Arctic region provide guidance to field observations and to GCMs on required improvements of future climate change simulations in the Arctic To synthesize understanding of past and present states and thus improve decadal to centennial prediction of future Arctic climate and its influence on global climate. RACM Science Objective

9. RACM Domains for Coupling and Topography -Innermost POP / CICE gridcell ≤10km - Middle – WRF / VIC gridcell ≤50km - Outermost – POP/WRF Pan-Arctic region to include: - all sea ice covered ocean in the northern hemisphere - Arctic river drainage - critical inter-ocean exchange and transport - large-scale atmospheric weather patterns (AO, NAO, PDO) Flux Coupler-CCSM/CPL7

10. Coupling of WRF and CPL7 Led by Juanxiong He with contributions from Greg Newby, Tony Craig, and Mark Seefeldt Minimize changes to WRF and CPL7 Add new surface routine to WRF to accept fluxes from CPL7 WRF/CPL7 working in global configuration Currently implementing regional domain with WRF/CPL7

11. Coupling of VIC and CPL7 Led by Dennis Lettenmaier and Chunmei Zhu with Tony Craig Currently have VIC coupled to CPL7 running in “data” mode Next step is to resolve issues with interactive VIC / atmosphere simulations

12. Coupling of POP / CICE with CPL7 Led by Wieslaw Maslowski, Jaromir Jakacki, Tony Craig and Gabriele Jost POP/CICE/CPL7 runs in a spinup mode with WRF in “data” and VIC in “slab” mode Minimal computational cost using CPL7

13. Modeled Sea Ice Thickness Loss NPS Arctic Model Effort (NAME): Sea ice thickness (m) in (a) 1982, (b) 1992, (c) 2002 (Maslowski et al., 2007)

14. Between 1997-2004: - annual mean sea ice concentration has concentration has decreased by ~17% decreased by ~17% - mean ice thickness has decreased by ~0.9 m decreased by ~0.9 m or ~36% or ~36% - ice volume decreased by 40%, which is >2x the 40%, which is >2x the rate of ice area decrease rate of ice area decrease Modeled Ice Extent, Thickness, and Volume

15. Ocean: Heat Transport Modeling challenge: Inflow of Pacific/Atlantic water and impacts on sea ice – Pacific water enters via narrow Bering Strait – Outflow via Fram Strait vs inflow from Atlantic bottom water – Heat loss from Pacific and Atlantic water prior to entering Arctic Mean Oceanic Heat Convergence (0-120 m)

16. Sea Ice Shear in CICE-9km Ice thickness distribution and deformations are critical to air- sea interactions and challenging to represent in GCMs

17. Finalize component model / CPL7 coupling Fully coupled simulations Evaluation of fully coupled model Multi-decadal simulations – Retrospective – Future climate Long-term goals – Regional simulations for IPCC reports – Additional climate system components Ice sheets Biogeochemistry RACM 2009-2010 Outlook