CCSM Biogeochemistry WG Plans

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CCSM Biogeochemistry WG Plans

• CCSM1-carbon
• Interactive land (CASA) and ocean (OCMIP) C
  cycles prognostic CO2 for atmospheric radiation
  
• Planned submission to IPCC 4th Assessment
• CCSM3-carbon
• Port CASA/OCMIP to CCSM3 physics
• Thorntons new land model (C-N coupling,
  disturbance)
• More advanced ocean (marine ecosystem dynamics)
• Planned submission to IPCC 4th Assessment
• CCSM3-carbon
• Dust ? marine productivity ? C
• Land atmosphere coupling and active chemistry

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Predicting Co-evolution of CO2 and Climate
Fossil Fuel 6 PgC/yr
3
Land BGC Module
CO2
H2O
Energy
LAI

• Based on coupling of CASA BGC Land
  Biogeophysics
• dynamic allocation
• prognostic LAI and phenolgy

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Marine BGC Module

• OCMIP Biotic Model
• prognostic export production
• iron limitation and cycling

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Coupling and Spin-up Strategy
CCSM 1.4 physics (with some changes) at T31/x3
CTracerprog CBGC280 CRad280
CTracerprog CBGCprog CRad280
CTracerprog CBGCprog CRadprog
land BGC spin-up active land/atm clim. or coupled
model SSTs O(102)y
coupled physics land/ocn BGC adjustment
coupled physics land/ocn/atm BGC adjustment
coupled physics fully coupled carbon-climate
ocean BGC spin-up active ocean O(103)y
c4.15 100 yr (11/5/03) start from y25 of
c4.14 280 ppm
c4.11 100 yr
c4.14 50 yr
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Carbon/Climate Control Simulation (100y)
1.0
14.1
-1.0
Net CO2 Flux
13.7
284
Surface Temp.
283
Stable carbon cycle and climate over O(100y)
with fully prognostic land/ocn BGC and
carbon/radiation coupling
282
Surface Atm. CO2
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Time-evolving, 3-D Atmospheric CO2 fields
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CCSM1-carbon Control and Fossil Fuel Experiments
Control (c4.15)
300 yr
1000 yr
1) Prescribed CO2 Emissions
CO2/Radiation Coupling
Run ensembles when feasible
2) Prescribed CO2 Emissions No
CO2/Radiation Coupling
3) Prescribed CO2 Concentrations
CO2/Radiation Coupling
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CCSM Carbon-Climate GCMs for IPCC 2007
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New Land BGC model
-Nitrogen/Carbon Coupling -Disturbance
NEE response to 1 C step change (decid
broadleaf)
N-limited
non N-limited
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Model GPP, Conterminous U.S. 18-year mean from
coupled carbon-nitrogen cycle model
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New Marine Ecosystem Model
Physical Framework -global POP-CCSM 2.0 (x3
grid) -multi-decade solutions OCMIP-Fe BGC
Model -ballast-model particle sinking and
remineralization -Fe scavenging as function of
particle flux -coastal sediment Fe
source Multi-element, multi-functional group
(Moore et al. 2002) -fixed C/N/P elemental
ratios (21 vs. 46 tracers) -variable Fe/C Si/C
Moore, Doney Lindsay (in prep.)
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Future/ongoing work
Upper Ocean Ecosystem Model -global seasonal
evaluation (draft manuscript) -historical and
JGOFS time-series/process study
sites -interannual variability (climate dust
flux)
Eco-BGC Coupling -quasi-equilibrium solutions (w/
LANL) -particle flux/ballast model -sediments (w/
U. Chicago)
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A less dusty future? Mahowald and Luo, 2003
Simulations using CSM 1for the first time make
estimates of future dust emissions. Use 6
different scenarios Estimates suggest 20-60
lower emissions/deposition in the future
(sensitive to model). Estimates in
pre-industrial sensitive to case (ice core data
does not constrain).

• Important implications
• natural aerosols such as mineral aerosols are
  HIGHLY sensitive to human activities.
• Important impacts on climate and ocean uptake of
  CO2 suggest significant feedbacks due to
  natural aerosol changes

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Future Natural Aerosol Work

• Online coupled simulations with other aerosols
• Online coupled simulations with ocean
  biogeochemistry
• Plans to include sea salts and natural biomass
  burning aerosol impacts
• Paleoclimate simulations to test model
  sensitivity and important feedbacks

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N forcing
Summary for Policymakers, IPCC 2001
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Putting the pieces together
The GLOBAL C CYCLE
The GLOBAL N CYCLE
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Harvest loss 11278 gC m-2
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What are the implications of N deposition for the
global carbon cycle with a simple perturbation
approach?
from Holland et al 1997, JGR Atmospheres
10215,849-15,866).