1. Dr. Lawrence Buja National Center for Atmospheric Research Boulder, Colorado, USA Dr. Lawrence Buja National Center for Atmospheric Research Boulder, Colorado, USA New Directions in Climate Research and Simulation: IPCC AR5 and US/NCAR Climate Modeling Activities

2. Image courtesy of Canada DND Recently, the direction of our climate change research program dramatically changed. WAS: Is anthropogenic climate change occurring? NOW: What will be the of impact of anthropogenic climate change on coupled human and natural systems? Magnitude and speed? Direct and indirect impacts? Adaptation vs mitigation What are our options & limits? Addressing these new, much more complex, questions requires new approaches & priorities, new science capabilities, new collaborators/partners

3. CCSP 2.1a Mitigation Simulations

5. MSE 3 Climate Topics Summary DOE’s ten-year vision to use exascale computing to revolutionize DOE’s approaches to energy, environmental sustainability and security global challenges. Exascale systems provide and unprecedented opportunity for science to use computation not only as an critical tool along with theory and experiment in understanding the behavior of the fundamental components of nature but also for fundamental discovery and exploration of the behavior of complex systems with billions of components including those involving humans. Download complete MSE 3 Report at http://www.er.doe.gov/ASCR/ProgramDocuments/TownHall.pdf

6. HPC dimensions of Climate Prediction Data Assimilation New Science Spatial Resolution Ensemble size Timescale Better Science (parameterization → explicit model) (new processes/interactions not previously included) (simulate finer details, regions & transients) (quantify statistical properties of simulation) (decadal prediction/ initial value forecasts) (Length of simulations * time step) Lawrence Buja (NCAR) / Tim Palmer (ECMWF)

7. Spatial Resolution (x*y*z) Ensemble size Timescale (Years*timestep) Today Terascale 5 50 500 Climate Model 70 10 2010 Petascale 1.4° 160km 0.2° 22km AMR 1000 400 1Km Regular 10000 Earth System Model 100yr* 20min 1000yr* 3min 1000yr * ? Code Rewrite Cost Multiplier Data Assimilation ESM+multiscale GCRM New Science Better Science HPC dimensions of Climate Prediction ? Lawrence Buja (NCAR) 10 2015 Exascale

8. Lawrence Buja (NCAR) Global General Atm/Ocn Circulation Continental Scale Flow Carbon Cycle + BGC Spinups Regional MJO/MLC Convergence IPCC AR3 1998 IPCC AR4 2004 4TF Sub-Regional Hurricanes IPCC AR5 2010 500TF CCSM Grand Challenge 2010 1PF

9. CCSM at ¼ ° ATM 1/10°OCN Courtesy Dr. David Bader, PCMDI/LLNL/DOE

10. IPCC AR4 Modeling Centers & AR5 Timeline

11. Aerosols –Direct and indirect effects Chemistry –Radiative and air quality issues Dynamic Vegetation –Regrowth following disturbance Carbon & Nitrogen Cycle –Ocean & land biogeochemistry –Anthropogenic (transient) land use/cover Land Ice Sheets –Sea level Rise & Abrupt Climate change New CCSM Components for IPCC AR5

12. IPCC AR5 (2013) Scenarios The AR5 process has much greater coordination between IPCC WG-I (Physical Science Basis)> WG-II (Impacts, Adaptation, Vulnerability and WG-III (Mitigation). 1. IPCC “Classic + ” Long-term (Mitigation) Scenarios: 100 & 300-year climate change simulations Medium resolution Core “required” + optional Tier 1 and Tier 2 simulations Carbon, Nitrogen & Biogeochemical cycles 4 Representative Concentration Pathways (RCPs) from IAM community Quantify investment return of mitigation strategies 2. New: Short-term Climate Change “Adaptation” Simulations: Short-term (30-year) climate predictions Single scenario High-resolution (0.5° or 0.25° resolution) Designed for impacts, policy and decision making communities.

13. NCAR RCPs in perspective – CO 2 emissions ( 671ppm, +3.7°, NIES ) ( 900ppm, +4.5°, IIASA ) ( 550ppm, +---°, PNNL ) ( 424ppm, <2°, MNP ) ( 370ppm, <2°, MNP ) From Moss et al., 2008

14. NCAR D & A ensembles Control, AMIP, & 20C RCP4.5 RCP8.5 ensembles : AMIP & 20 C natural-only, GHG-only individual forcing RCP2.X, RCP6 extend RCP4.5 to 2300 extend RCP8.5 & RCP2.X to 2300 ensemble of abrupt 4xCO2 5-yr runs Radiation code sees 1XCO2 (1% or RCP4.5) aqua planet unform ΔSST Mid-Holocene & LGM last millennium E-driven RCP8.5 E-driven 20 C patterned ΔSST sulfate aerosol forcing in 2000? sulfate aerosol forcing in 1960? 1%/yr CO 2 (140 yrs) abrupt 4XCO 2 (150 yrs) fixed SST with 1x & 4xCO 2 E-driven control with C-cycle CMIP5 Long-term Experiments Coupled carbon-cycle climate models only All simulations except those “E-driven” are forced by prescribed concentrations Carbon cycle sees 1XCO2 (1% or RCP4.5)

15. NCAR CMIP5 Decadal Predictability/Prediction Exps Additional predictions Initialized in ‘01, ’02, ’03 … ‘09 100-yr “control” & 1% CO2 prediction with 2010 Pinatubo-like eruption Alternative initialization strategies regional air quality More complete atmos. chemistry &/or aerosol treatment prescribed SST time- slices extended ensembles to O(10) extreme event analysis hindcasts sans volcanoes 30 year initialized hindcasts & predictions O(3) 10 year initialized hindcasts & predictions, O(3)

16. Temperature at 2030 Averages and Extremes (IPCC AR4: no C-cycle/dynVeg feedback)

17. Precipitation at 2030 Averages and Extremes (IPCC AR4: no C-cycle/dynVeg feedback)

18. From: Earth System Grid Center for Enabling Technologies: (ESG-CET) Petabyte-scale data volumes Globally federated sites “Virtual Datasets” created through subsetting and aggregation Metadata-based search and discovery Bulk data access Web-based and analysis tool access Increased flexibility and robustness ESG Goals Current ESG Sites http://www.earthsystemgrid.orghttp://www-pcmdi.llnl.gov DATA: Earth System Grid Center for Enabling Technologies (ESG-CET) For AR5, ESG will be expanded to form a global virtual data center!

19. NCAR Towards a Next Generation Climate-Weather-ESM Existing and future applications require (at least locally) meso-scale and cloud-scale resolution in a global model Current climate models are poor weather models, and current weather models are poor climate models. Opportunity to leverage the diverse interests and experience of the climate and weather communities to create and share a next-generation atmospheric simulation system. New dynamic grids and solution methods capable of efficient operation on petascale computers Nested Regional Climate Model

20. NCAR North Atlantic and North American Regional Climate Changes The goal is to simulate the effects of climate change on precipitation across the intermountain West States and tropical cyclones, with a focus on the Gulf of Mexico. 36, 12 and 4 km domains nested into CCSM 1996-2005, then time slices out to 2050 Multi-member ensembles for each period Dedicated time on NCAR IBM Power 6 (Bluefire) since July:  24 nodes (~20% of total number of processors)  36 (12) km simulations use 128 (256) processors per job  Will use 3.9M processor hours through 11/08  ~300 Tb of data (to date); 450 Tb total (including earlier runs)

21. NCAR Improving Predictions of Regional Changes in Weather and Climate The Nested Regional Climate Model IPCC (2007)IPCC (2013)NRCM High Resolution Climate Modeling

22. NCAR Importance of Resolution 18 storms 25 storms

23. NCAR Thanks! Any Questions?

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