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