gfdl’s coupled and earth system model developments high-resolution atmosphere and oceans ...
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GFDL’s Coupled and Earth System Model Developments
• High-resolution Atmosphere and Oceans horizontal (capturing regional, other fine-scale details), vertical (capturing the stratosphere)
• Climate Models graduating onto Earth Systems Model, including interactive Atmospheric Chemistry (capturing Climate – Air Quality nexus) and Biogeochemistry (capturing Carbon-Climate feedbacks)
• Need for comprehensiveness and realism in representation of processes
Earth system/comprehensiveness pipeline
Precip in 25 km model Surface NOX in AM3 (200 km)
Resolution pipeline
Merge in future
Model development strategy within GFDL: 2 pipelines developed in tandem push atmospheric and oceanic climate models to higher resolution, while developing and utilizing lower resolution Earth System Models
Winter mean precipitation in Western U.S. in 50km model
200 km res. 50 km res. Observations
Annual meanprecipitation in Europe 200km 50km
2 deg. 1/2 deg.
GFDL Model rainfallCurrent generation
Developing generation
Observed SST and Wind
From Vecchi, Xie and Fischer (2004, J. Clim)Model data: S.J. Lin, I. Held, M. Zhao
To resolve societally and physically relevant scales:
High-res. atmosphere, ocean, coupled models being developed at GFDL
High resolution simulation of Southern Ocean
(Hallberg and Gnanadesikan, JPO, 2006)
Small vortices affect oceanic carbon uptake heat, transport of heat towards Antarctic continent, marine ecology of Southern Ocean
Development Pathway:Coupled Model for AR5
CM3 = AM3 + LM3 + CM2.1 ICE/OCEAN
ESM2.1 = CM2.1 + LM3V + OBGC
CM2G = CM2.1 with GOLD
CM2M = CM2.1 with MOM+ ESM2M
ESM2G
2008
5yr/day on 500PEs
2400 CPUhr/yr
8yr/day on 140PEs
425 CPUhr/yr
10yr/day on 120PEs
300 CPUhr/yr
Why two ocean models?
z-coordinate better in weakly stratified regions
-coordinate better on sloping bottom
Role of ocean in
transient climate
change?
LM2 -> LM3 Land Model
Dynamic vegetation
Subgrid land-use heterogeneity
Distinct treatment of ground,
vegetation, & canopy air
Soil water dynamics (liquid & frozen)
Multilayer snow pack
River network with capacity for tracers
and temperature
Decadal Predictability Research
• Ongoing studies with CM2 model to develop improved understanding of a) mechanisms of decadal variabilityb)decadal scale predictability arising from
internal variability
• Development and use of higher resolution coupled models. Want this to be focus of variability and predictability research
• New coupled assimilation system
More intense hurricanes
Drought
More rain over Saheland western India
Warm North Atlantic linked to …
Two important aspects:a. Decadal-multidecadal fluctuationsb. Long-term trend
Atlantic Meridional Overturning Circulation (AMOC)
North Atlantic Temperature
What will the next decade or two bring?
Simulated North Atlantic AMOC Index
Aerosol only forcingAll forcings
Greenhouse gas only forcing
Projected Atlantic SST Change (relative to 1991-2004 mean)
Results from GFDL CM2.1 Global Climate Model
Can we predict which trajectory the real climate system will follow?
Decadal Predictability• Decadal prediction/projection is a mixture of boundary
forced and initial value problem
• Changing radiative forcing (esp. aerosols) will be a key ingredient
• Some basis for decadal predictability of internal variability, probably originating in ocean
• Some of predictability will arise from unrealized climate change already in the system
• Substantial challenge for models, observations, assimilation systems, and theoretical understanding
Earth System Modeling
• What proportion of Fossil Fuel CO2 emissions will stay in the
atmosphere, and for how long?
• What are the ecological impacts of increased CO2 and ocean
acidification?
• What are the ecological impacts of climate change?
• What is the role of land use on carbon cycling?
• How effective can proposed CO2 sequestration approaches be
(e.g. iron fertilization, deep ocean CO2 injection, forest
preservation)?
GFDL’s earth system model (ESM) for coupled carbon-climate
Land physicsand hydrologyOcean circulation
Atmospheric circulation and radiation
Land physicsand hydrology
Ocean ecology andBiogeochemistry
Atmospheric circulation and radiation
Chemistry – CO2, NOx, SO4, aerosols, etc
Ocean circulation
Plant ecology andland use
Climate Model
Earth System Model
Sea IceLand Ice
Sea IceLand Ice
IPCCAR4 WG1
Chapter 10
Ocean processes represented in GFDL’s current ESM
• Coupled C, N, P, Fe, Si, Alkalinity, O2 and clay cycles• Phytoplankton functional groups
– Small (cyanobacteria) / Large (diatoms/eukaryotes) – Calcifiers and N2 fixers
• Herbivory - microbial loop / mesozooplankton (filter feeders)
• Variable Chl:C:N:P:Si:Fe stoichiometry• Carbon chemistry/ocean acidification• Atmospheric gas exchange deposition and river fluxes• Water column denitrification• Sediment N, Fe, CaCO3, clay interactions
Current land processes represented in GFDL’s current ESM
• Plant growth– Photosynthesis and respiration – f(CO2, H2O, light, temperature)– Carbon allocation to leaves, soft/hard wood, coarse/fine roots, storage
• Plant functional diversity– Tropical evergreen/coniferous/deciduous trees, warm/cold grasses
• Dynamic vegetation distribution– Competition between plant functional types– Natural fire disturbance – f(drought, biomass)
• Land use– Cropland, pastures, natural and secondary lands– Conversion of natural and secondary lands and abandonment– Agricultural and wood harvesting and resultant fluxes
in collaboration with PU, UNH and USGS(Schevliakova et al., subm GBC; Malyshev et al., in prep)
Work in progress: repeating these runs with a comprehensive ecosystem model
Nutrients
NO3NH4
Si
PO4
Fe
Phytoplankton
Diazotrophs
Small plankton
Large Plankton
DOP,DON
Zooplankton (parameterized)
DOP, DON
Sinking particles
(POM, CaCO3, Opal, Fe)
Oxygen
Dissolved components
Oxygen
CaCO3
Remineralization/ dissolution
Remineralization/ dissolution
Burial (CaCO3, Fe)
N fixation
Deposition (N, Fe) Runoff (CaCO3,N)
Denitrification
Dunne et al., in prep.
Observations ModelL
og
(Ch
l)N
O3
PO
4
Moving towards the future of Earth System Modeling (ESM3 and beyond)
• Coupling with atmospheric chemistry
• Coupling with river biogeochemistry
• Integrated elemental cycles beyond carbon– N, P, Fe, CH4
• Seasonal fire dynamics
• Coastal and estuarine interactions
• Ecological prediction of hypoxia, harmful algal blooms and fisheries capacity variability
River Routing
Hypoxia events
Harmful algal blooms
Land-use and ecology Nitrogen runoff
Atmospheric chemistry
Future Model Applications:Ecological Prediction Example
Doubles every ≥2 years10x every ≥7 years
FY2007 Project Summary
Project % of R&D HPCS (Princeton)
CPU-hours per year
Climate Scenario Analysis
10 3,800,000
Climate Scenario Generation
20 7,600,000
Software Infrastructure Development
5 1,900,000
Next Generation Ocean Model R&D
15 5,700,000
Long-term Climate Model R&D
40 15,300,000
Seasonal Climate Modeling R&D
10 3,800,000
TOTAL 100 38,100,000
DEC-CEN Computing Gaps• Computing gaps are associated primarily with requirements for
– Increased resolution• To meet demands for information on water resources, extreme events, and
ecosystems at regional scales.• CM2.4, the target model for GFDL’s Decadal Prediction research, is 25x
more expensive to run than CM2.1, one of its AR4-class models– Additional comprehensiveness
• Fully interactive cycles of many chemical species in the atmosphere, land, rivers, and ocean
• Direct and indirect aerosol effects• Ice sheets (eventually)• ESM2.1 is ≤2x more expensive to run than CM2.1• CM3 is 5x more expensive to run than ESM2.1
– Ensemble members• Using different initial conditions• Increasing number of assessments
– Technology will provide about 6-8x between AR4 and AR5• State-of-the-art computing is crucial for recruiting and retaining top-
notch scientific talent
The Challenges
Increasing the realism, capturing the complexities and addressing the key uncertainties
Coupling of the components Climate, Earth System Models
Performing high-resolution simulations
Increased ensemble member integrations
Meeting timelines (e.g., for major assessments)
Schematic for Global Atmospheric Model
Vertical Grid (Height or Pressure)
Horizontal Grid (Latitude-Longitude)
Schematic for Global Atmospheric Model
Vertical Grid (Height or Pressure)
Horizontal Grid (Latitude-Longitude)
Global Climate Model
Critical Resources
Computational (“Computer-ware”)
Scientific talent (“Brainware”)
END