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Coupled BGC-Climate Experiments. Leap0: CCSM1 ( aka WCRP-IGBP C4MIP) Interactive land and ocean C cycles, Prognostic CO 2 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 .
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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 Breckinridge, 6/01
Atmosphere Model Applications • CO2inversions (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 Breckinridge, 6/01
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) Breckinridge, 6/01
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) Breckinridge, 6/01
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) Breckinridge, 6/01
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 Breckinridge, 6/01
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 Breckinridge, 6/01
Potential growth: carbon/BGC data assimilation – • CO2 satellite hopeful • CCSM only comprehensive C-climate model in US • collaboration with DAO Breckinridge, 6/01