Coupled BGCClimate Experiments

1
Coupled BGC-Climate Experiments

• Leap0 CCSM1 ( aka WCRP-IGBP C4MIP)
• Interactive land and ocean C cycles, Prognostic
  CO2 in atm.
• Successful coupling of ocean BGC to CCSM1 30
  year spin-up so far and running. Successful
  implementation of land BGC modules. Flexible
  architecture.
• Leap1 CCSM2
• Dust ? marine productivity ? C
• Ongoing development and testing of dust cycle
  (Mahowald) and marine ecosystem model (Moore)
• Helps focus module development and scientific
  investigations

2
Atmosphere Model Applications

• CO2 inversions (Dargaville, Chen, Bruhwiler,
  Baker) US C sink not so huge
• Assimilation of AVHRR aerosol data (Collins
  Rasch)
• Forward modeling of dust cycle changes in LGM
  and 21st century (Mahowald)
• Forward modeling of SF6 - diagnose transport in
  CCM (Dargaville)
• Water isotopes for interpreting CO18O,
  understanding climate proxies, diagnosing water
  cycle (Noone)

MATCH
CAM-LSM
3
Atmospheric Tracer Transport Model

• MATCH (Rasch) off-line NCAR model widely used,
  minimally supported
• Importance of atm circ. variability/
  uncertainties in interpreting CO2 variations
• 3 entries (out of 20) in IGBP TransCom - (Chen,
  Law, Bruhwiler)
• Only model with 20 yr interannual transport to
  investigate transport vs source/sink variability
  (Dargaville)
• Simulations of SF6, CO2(z in PBL) ? additional
  tests of circ statistics in GCM (Dargaville,
  Bruhwiler)

4
Ocean BGC

• Migration of OCMIP2 BGC model to POP (Lindsay)
• New ocean ecosystem model Fe, Si (Moore)
• 50 of world ocean is Fe limited
• Computational not unreasonable
• Successful implementation of C-13 in BGC (Fung)
• diagnostic of ocean carbon processes and their
  competition
• Planned implementation of additional tracers to
  diagnose C cycle oxygen (Stephens)

5
Land BGC

• Flexible architecture in CLM2 for community
  development of BGC modules (Bonan)
• Community enthusiasm for development and
  applications of CLM2-BGC
• Interactive land N-C cycles ready for CLM2
  (Thornton)
• Disturbance frequency, intensity, and recovery
  dynamics dynamic vegetation (Thornton, Bonan et
  al.)
• Dust (Mahowald and Zender)
• Need to incorporate BGC in CLM2 river runoff
  for coupling to coastal/open ocean BGC
  (Sundquist)

6
Issues

• BGC model development, model diagnostic, and
  model application.
• Recommend addition of a standard suite of tracers
  in CAM2 and COM2 to diagnose transport
• CAM SF6 (interhem.), radon (convective), Simple
  strat O3 (strat-trop), blobs at low, mid, upper
  trop
• COM CFC (101-102 yr), 14C(102-103 yr),
• Recommend addition of Constrained Transport
  Module into CCSM for diagnosing land or ocean
  sources/sinks

7

• Need procedure for community access to b
  versions of CAM2, CLM2, COM2 codes for BGC
  development
• Code documentation
• ? email to WG co-chairs stating scientific plan,
  will not distribute, will share code with CCSM
  community afterwards,
• Computer codes, platforms, computer time
• How do we keep up with fast evolution

8

• Potential growth carbon/BGC data assimilation
  
• CO2 satellite hopeful
• CCSM only comprehensive C-climate model in US
• collaboration with DAO