October 2001- June 14, 2002

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Progress in the theme areas

The terrestrial theme is progressing well and is currently ahead of the targets listed in the timeline of the proposal. The terrestrial group is developing two research versions and one operational version of the terrestrial model. This will allow for maximizing the expertise in the group and promote diversity in the approaches to particular model parameterizations. Currently there are McMaster-UBC and U. Alberta versions of C-CLASS – a version of CLASS expanded to include carbon cycle processes. Both these models are in various states of development and evaluation. While they contain the same basic structure they approach photosynthesis, autotrophic and particularly heterotrophic respiration slightly differently. The carbon allocation is more developed in the U. Alberta version and it contains an elementary nitrogen cycle. Based on these two models CCCma is inserting the algorithms into the existing CGCM for coupled carbon-climate simulations. This is what is referred to here as the operational version.

Specific work accomplished over the first six months in the terrestrial theme includes:

1. education of the ocean and atmospheric collaborators on various aspects of the terrestrial carbon cycle and what the critical issues and components are;
2. exchange of information amongst the terrestrial modellers on the different ways of treating the main functional components of the terrestrial carbon cycle in the different versions of C-CLASS and the Peatlands Carbon Simulator (PCARS);
3. implementation, based on the previous versions of C-CLASS, the algorithms to incorporate photosynthesis, autotrophic and heterotrophic respiration into the operational version, and detailed evaluation using Ameriflux data sets (CCCma);
4. continued development of the functions for C4 photosynthetic pathways and evaluating this approach against the HAPEX-Sahel data sets (McMaster)
5. continued evaluation of various approaches to incorporate stomatal conductance and begin evaluating against ABRACOS (tropical forest) data sets (McMaster);
6. integration of a three-layer multiple-partitioned soil carbon decomposition and respiration approach based on CENTURY and evaluation against grassland and aspen forest flux data (U. Alberta);
7. development of a multilayer soil climate model (UBC) and a flexible multilayer version of the CLASS soil climate model (McGill) to be used to evaluate the sensitivity and uncertainty from using the three soil layers in the current version of CLASS;
8. examining the performance of simplified functions for describing photosynthesis (UBC);
9. further evaluation of the PCARS model against the four year carbon exchange data set from the Mer Bleue observatory (McGill); and
10. investigating simple ways of incorporating aerobic and anaerobic decomposition pathways into a soil respiration model (McGill).

The ocean model group is building on preliminary work begun under the carbon node of the CRN. Over the last six months this work has continued. They previously developed a full inorganic carbon model for the oceans and are currently working on developing a multi-compartment organic carbon model for the ocean.

Specific work accomplished over the first six months in the ocean theme includes:

1. education of the terrestrial and atmospheric collaborators on various aspects of the ocean carbon cycle and what the critical issues and components are;
2. conducting OCMIP-2 tracer experiments, and comparing results with observations of 14C, and CFCs obtained during the GEOSECS, TTO, and WOCE global surveys;
3. using current global air-sea CO2 flux estimates with abiotic model (this will be replaced with modelled ocean surface pCO2, wind speeds, and atmospheric CO2 concentrations in the coupled model) and;
4. continued implementation of OCMIP-2 nutrient nudging biology with the inorganic C module.

Of the three theme areas this has received the least immediate attention, largely because it is farther ahead. There has been significant effort in the development of a new coupler that will accommodate the various components that need to exchange information during a climate simulation. In addition this group is building on the work done under other projects related to the issues of atmospheric chemistry. They have not yet been successful in securing a PDF/RA to assist in the model development related to the atmospheric component of the model. However, CCCma has been successful in attracting a PDF from the Max Planck Institute for Global Biogeochemistry to assist with the development of the dynamic vegetation component of the terrestrial carbon model. This will contribute significantly to in-house expertise on the terrestrial carbon cycle.

1. education of the terrestrial and atmospheric collaborators on various aspects of the ocean carbon cycle and what the critical issues and components are;
2. investigation of the use of a simplified chemistry package in the AGCM (i.e. parameterized chemical loss rates for CH4, N2O) developed by Jack McConnell based on the York U CTM (chemical transport model) which has the same chemistry in it as is in the Canadian Middle Atmosphere Model (CMAM). The simplified chemistry specifies parameterized loss rates (varying within season, latitude and height);
3. implementation and testing of a version the CMAM at CCCMA with a fairly complete gas phase chemistry package. The simplified chemistry in the AGCM will be compared over the next year to the full CMAM chemistry.

Deviations from original objectives or planned allocation of resources

There have been no deviations from what was outlined in the originally proposal. There have been no major alterations in the allocation of the funding to the various components of the project. Two areas where there have been slight deviations or delays are: a) we have not yet secured a PDF/RA for the atmospheric theme area but the search continues, and b) we have held one more science workshop than we had anticipated. Based on progress so far it is anticipated that three science workshops per year will be held rather than two as originally described in the proposal. We are finding these workshops extremely productive.