Dr. Lawrence Buja National Center for Atmospheric Research Boulder, Colorado, USA

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

2. 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 Image courtesy of Canada DND

3. CCSP 2.1a Mitigation Simulations

5. MSE3 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 MSE3 Report at http://www.er.doe.gov/ASCR/ProgramDocuments/TownHall.pdf

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

7. 70 10 10 10 10 10 10 10 10 HPC dimensions of Climate Prediction • New Science • Better Science ESM+multiscale GCRM Code Rewrite Earth System Model • Spatial • Resolution • (x*y*z) Climate Model • Timescale • (Years*timestep) Regular10000 ? 400 0.2° 22km 1.4° 160km 1Km 100yr* 20min 1000yr* 3min 1000yr * ? AMR 1000 5 Today Terascale 2010 Petascale 50 Cost Multiplier 500 2015 Exascale Data Assimilation • Ensemble size Lawrence Buja (NCAR)

8. Continental Scale FlowCarbon Cycle + BGC Spinups RegionalMJO/MLC Convergence IPCC AR3 1998 GlobalGeneral Atm/OcnCirculation IPCC AR4 2004 4TF IPCC AR5 2010 500TF Sub-RegionalHurricanes CCSM Grand Challenge 2010 1PF Lawrence Buja (NCAR)

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

10. IPCC AR4 Modeling Centers & AR5 Timeline

11. New CCSM Components for IPCC AR5 • 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

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. RCPs in perspective – CO2 emissions ( 900ppm, +4.5°, IIASA ) ( 671ppm, +3.7°, NIES ) ( 550ppm, +---°, PNNL ) ( 424ppm, <2°, MNP ) ( 370ppm, <2°, MNP ) From Moss et al., 2008

14. individual forcing ensembles: AMIP & 20 C D & A ensembles extend RCP8.5 & RCP2.X to 2300 RCP2.X, RCP6 natural-only, GHG-only RCP4.5 RCP8.5 extend RCP4.5 to 2300 Control, AMIP, & 20C lastmillennium Mid-Holocene & LGM E-driven RCP8.5 E-driven 20 C 1%/yr CO2 (140 yrs) abrupt 4XCO2 (150 yrs) fixed SST with 1x & 4xCO2 E-driven control with C-cycle aqua planet ensemble of abrupt 4xCO2 5-yr runs patterned ΔSST sulfate aerosol forcing in 2000? unform ΔSST Radiation code sees 1XCO2 (1% or RCP4.5) sulfate aerosol forcing in 1960? CMIP5 Long-term Experiments All simulations except those “E-driven” are forced by prescribed concentrations Carbon cycle sees 1XCO2 (1% or RCP4.5) Coupled carbon-cycle climate models only

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

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) DATA: Earth System Grid Center for Enabling Technologies (ESG-CET) Current ESG Sites ESG Goals • 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 http://www.earthsystemgrid.org http://www-pcmdi.llnl.gov For AR5, ESG will be expanded to form a global virtual data center!

19. 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. North Atlantic and North American Regional Climate Changes • 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) 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.

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

22. Importance of Resolution 18 storms 25 storms

23. Thanks! Any Questions?

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