State of the Community Climate System Model (CCSM) Peter Gent Chairman CCSM Scientific Steering Committee gent@ucar.edu

Recent Science Highlights CCSM IJHPCA Special Issue Objectives Describe SE for climate models Document performance and portability 13 papers published in Fall 2005, Volume 19, Number 3 Authorship 32 External 9 NCAR

Recent Science Highlights CCSM J. Climate Special Issue 26 papers accepted SSC (1) Atmosphere Model (6) Ocean Model (4) Land Model (2) Climate Change (2) Climate Variability (4) Polar Climate(4) Paleoclimate (3) 570 pages (estimated) Authorship 51 NCAR (22 lead authors) 48 External

Contributions to IPCC Fourth Assessment Output: 10 GB/simulated year Data volume for IPCC: ~100 TB Largest contribution of any model Eight ensemble members at T85 for some experiments Data available online: PCMDI (IPCC archive) ESG (Control) Original history tapes: SCD Diagnostics on line (web)

Ts> = 8°C Kiehl and Shields Global Annual Mean Energy Budget Forcing of 10X increase in CO2 and Permian paleogeography Permian coupled model run for 2700 years to new equilibrium state Kiehl and Shields CCSM3 T31X3 Ts> = 8°C Global Annual Mean Surface Temperature

Inefficient mixing in Permian ocean indicative of anoxia Kiehl and Shields (2005)

Sea Ice Area in Hosing Experiments LGM Cecilia Bitz et al. April Modern LGM Modern September

Vertical Freshwater Flux Averaged over Hosing Area Cecilia Bitz et al.

Near-term Scientific Priorities Get a good coupled simulation using the finite volume dynamical core; need a sea-ice distribution that is comparable to, or better than, the CCSM3 simulation Improve the simulation in the tropical Pacific region; especially the double ITCZ and the frequency of ENSO Several of the most pressing scientific questions regarding the climate system and its response to natural and anthropogenic forcings cannot be readily addressed with traditional models of the physical climate. While the ultimate goal is a comprehensive Earth System Model (ESM), practical considerations suggest that there will be a multitude of versions with different capabilities. The CCSM project will work towards developing a first generation coupled chemistry-climate model in the next two to three years. A project of this scope will necessarily involve scientific partnerships across ESSL, NCAR and the external CCSM community. This model could be used to study the complex interactions among biota, chemical processes, and physical climate for paleoclimate studies or scenarios for future climate change. It could also be used to study variations of the chemistry of the present-day atmosphere driven by external forcing from solar variability and major internal natural modes of variability, such as ENSO. The ocean ecosystem module includes multiple phytoplankton functional groups, limitations by several major nutrients, nitrogen fixation, and treatments of sinking and remineralization of biological material. The terrestrial module can simulate multiple agricultural plant types and human-mediated disturbance of the land surface. Both of these modules are now being tested to understand their equilibrium behavior.

Finite Volume Core Change in gravity wave drag and low level drag

Sea Ice from 1x1.25 FV

WRF 36 km res global channel Precipitation in 1996 CAM3 at T170 res

Correct amplitude Tropical Instability Waves in ocean component with reduced horizontal viscosity: M Jochum

Zonal windstress across the equatorial Pacific Ocean

NINO3 spectra: Black – obs, blue – control, red – new

Some major issues in CCSM Simulations Temperature and Precipitation Biases in mid-lat. continental temp. and precipitation SSTs in coastal stratus regions Semi-annual cycle in SST for the E. Pacific Polar temperature bias and tropical tropopause biases Double ITCZ in the Pacific Representation of major modes of variability El Nino / Southern Oscillation The Madden-Julian oscillation

Continental Temperature and Precipitation Collins et al, 2005

Madden-Julian Oscillation Propagation Collins et al, 2005

Longer-term Scientific Priorities Include biogeochemistry and ocean ecosystem model for the carbon/nitrogen cycle Include dynamic vegetation and land use changes in the land component Include both the direct and indirect effects of aerosols Atmospheric chemistry component has been added; include the effects of tropospheric ozone? Include a land ice sheet model Several of the most pressing scientific questions regarding the climate system and its response to natural and anthropogenic forcings cannot be readily addressed with traditional models of the physical climate. While the ultimate goal is a comprehensive Earth System Model (ESM), practical considerations suggest that there will be a multitude of versions with different capabilities. The CCSM project will work towards developing a first generation coupled chemistry-climate model in the next two to three years. A project of this scope will necessarily involve scientific partnerships across ESSL, NCAR and the external CCSM community. This model could be used to study the complex interactions among biota, chemical processes, and physical climate for paleoclimate studies or scenarios for future climate change. It could also be used to study variations of the chemistry of the present-day atmosphere driven by external forcing from solar variability and major internal natural modes of variability, such as ENSO. The ocean ecosystem module includes multiple phytoplankton functional groups, limitations by several major nutrients, nitrogen fixation, and treatments of sinking and remineralization of biological material. The terrestrial module can simulate multiple agricultural plant types and human-mediated disturbance of the land surface. Both of these modules are now being tested to understand their equilibrium behavior.

Multi-Century Coupled Carbon/Climate Simulations +2.0 14.1 13.6 -2.0 Surface Temp. Net CO2 Flux (Pg C/yr) year 1000 year 1000 Fully prognostic land/ocn BGC and carbon/radiation Atm-Land CO2 flux: 70 PgC/yr ; Atm-Ocean CO2 flux: 90 PgC/yr  Net Land+ocean CO2 flux: 01 PgC/yr “Stable” carbon cycle and climate over 1000 years Doney, Lindsay, Fung and John: Accepted by J Climate

Flux of CO2 into the world oceans (Ocean ecosystem model) Moore, Doney, and Lindsay

Land carbon cycle sensitivity to [CO2]atm: influence of Ndep IPSL and Hadley CSM1/CASA’ ? Offline: CO2+Ndep This shows the land carbon cycle sensitivity to CO2 (referred to as the beta factor) compared between CAM-CLM3CN (the blue lines), CSM1-CASA’ (green diamonds) and IPSL and Hadley results (blue triangles – values nearly the same for these two models). This figure shows that the CLM3CN model has a significantly lower beta factor than CASA’, and that both models have much lower beta factor than eaither Hadley or IPSL models. A lower beta value means that the model takes up less carbon (PgC/yr) per unit increase in CO2 concentration (ppmv/yr). The low beta factor for CLM3CN is the expected result, given the limiting effect of carbon-nitrogen cycle interactions on ecosystem carbon uptake potential under CO2 fertilization. This is illustrated by showing that introducing the effects of industrial nitrogen deposition increases the CLM3CN beta factor (dashed blue line). The red lines are from the coupled model run, and they are included to show that the beta factor is in the same neighborhood for cuopled and offline simulations, but the coupled runs are not long enough to make any conclusive statement about the time course of the beta factor. This really has to wait for the fully coupled runs with the ocean ecosystem, which are underway now. The combined story from these two slides is that including the coupled dynamics of the carbon and nitrogen cycles tends to have a buffering effect on the sensitivity of the land carbon cycle: less sensitive to temperature and less sensitive to CO2, than for models that don’t include the C-N dynamics. This suggests that the model response to warming will be less of a carbon source, but that the land has a smaller capacity to take up future anthropogenic CO2 emissions. How these effects interact to produce a future CO2 trajectory remains to be seen, but it is clear that including these interactions will result in very different coupled system dynamics, compared to previous implementations that have ignored the C-N interactions. Peter Thornton et al. Offline: CO2 CAM-CLM3CN

Historical changes in agricultural land use Johan Feddema

Response of the chemistry-climate system to changes in aerosols emissions. scaling of SO2, NH3, BC, and POA scaling of SO2, NH3, BC, and POA The hydrological cycle (measured here by the global integral of the precipitable water) slows down with increasing aerosol loading Without any changes to surface emissions of ozone precursors, the global integrals (surface to 200 hPa) of OH, ozone and NOx(=NO+NO2) show a large increase from decreasing aerosols. This is due to a combination of an increase in water vapor and reduced uptake on aerosols of HO2, N2O5 and NO2. From Lamarque et al., GRL, 2005

Response of ozone to increasing methane At the Permian-Triassic boundary (250 Ma), there was possibly a large release of methane from clathrates. To simulate the impact of this methane on ozone, we have used WACCM (reduced to 85 km) forced by the paleogeography and boundary conditions from Kiehl and Shields [2005]. The x-axis is the scaling of tropospheric methane from 1x (700 ppbv) to 5000x (this whole range is plausible). There is ozone collapse starting from around 750x. This decrease in ozone and increase in UV could play an important role in the mass extinction at that time. From Lamarque et al., submitted to Paleoceanography, 2006

Annual accumulation (Bales et al., 2001) Greenland ice sheet Volume ~ 2.8 million km3 (~7 m sea level equivalent) Area ~ 1.7 million km2 Mean thickness ~ 1.6 km Accumulation ~ 500 km3/yr Surface runoff ~ 300 km3/yr Iceberg calving ~ 200 km3/yr Bill Lipscomb, LANL Annual accumulation (Bales et al., 2001)

Potential Configuration of CCSM4 Coupler Land Atmosphere Ocean Sea Ice C/N Cycle Dyn. Veg. Land Use Ecosystem & BGC Gas chem. Prognostic Aerosols Upper Atm. Hansen and Sato, 2001

Increased Computer Time for CCSM Climate Simulation Lab. Blue Vista is now online. CCSM allocated 2.5M GAUs over 18 months; 89% of request; 61% of total allocated. Climate End Station. Oak Ridge Cray X1E & XT3 CCSM Development (Gent) 0.5M 0.3M Biogeochemistry (NCAR, ORNL) 0.7M 0.1M Climate Change (Washington) 0.5M High-Res Atmosphere (Hack) 0.2M Total of 2.3M hours in FY06. Increase of 50% in CGD’s 06 computer allocation.

Computational Characteristics of CCSM3 CCSM3 has been climate-validated and run on: IBM Power 3 and 4 systems SGI Altix systems SGI Origin systems Cray X1 vector systems (work on XT3 and XD1 underway) NEC SX vector systems Specific Xeon linux systems (work on Opteron underway) Computational requirements for CCSM3 on Power 4s: T31 land/atm  3o ocean/ice: 62 CPU hrs/sim. year T42 land/atm  1o ocean/ice: 292 CPU hrs/sim. year T85 land/atm  1o ocean/ice: 1146 CPU hrs/sim. year

CCSM FY 2006 Funding NSF Base Funds (Project Leader, travel, misc.) $99,000 CMAP Funds Scientists 0.7 FTE $191,400 CSEG 5.0 FTE $862,000 Working Group Liaisons 3.2 FTE $446,000 Atmosphere, Ocean, Land, Biogeo Admin Support/Project Office 0.75 FTE $ 94,000 Meetings and Workshop $165,000 Total $1,758,400 NSF Special Funds SE (Portability) 0.50 FTE $ 90,000 Polar WG Liaison 1.0 FTE $150,000 Total $240,000 Other (Killeen) – SE (Portability) 0.50 FTE $ 94,300

CCSM FY 2007 Funding Needs Polar Climate WG Liaison (David Bailey); Funds carry through December 2006. Proposal submitted to NSF Polar Programs. Software Engineer on NSF Special and Other Funds (Jon Wolfe). Funds through FY 2006. Software Engineer on 1/3 NASA ESMF, 1/3 Killeen, and 1/3 CGD Funds (Erik Kluzek). Funds through FY 2006. DOE SciDAC I Proposal. Funds through FY06. $501,200 DOE SciDAC II Proposal. To be submitted. $714,000

CONCLUSIONS IPCC work and special journal issues have gone well. Near term developments - not successful yet, but a much greater concerted effort than previously. Longer term efforts - Biogeochemistry and Land developments well underway; indirect aerosol, atmospheric chemistry and land ice just starting. Nice increase in CCSM computer time (NSF and DOE). Biggest problem is to maintain and increase support for the CCSM Software Engineering Group and liasons. Several of the most pressing scientific questions regarding the climate system and its response to natural and anthropogenic forcings cannot be readily addressed with traditional models of the physical climate. While the ultimate goal is a comprehensive Earth System Model (ESM), practical considerations suggest that there will be a multitude of versions with different capabilities. The CCSM project will work towards developing a first generation coupled chemistry-climate model in the next two to three years. A project of this scope will necessarily involve scientific partnerships across ESSL, NCAR and the external CCSM community. This model could be used to study the complex interactions among biota, chemical processes, and physical climate for paleoclimate studies or scenarios for future climate change. It could also be used to study variations of the chemistry of the present-day atmosphere driven by external forcing from solar variability and major internal natural modes of variability, such as ENSO. The ocean ecosystem module includes multiple phytoplankton functional groups, limitations by several major nutrients, nitrogen fixation, and treatments of sinking and remineralization of biological material. The terrestrial module can simulate multiple agricultural plant types and human-mediated disturbance of the land surface. Both of these modules are now being tested to understand their equilibrium behavior.