QUERCC: QUantifying Ecosystem Roles in the Carbon Cycle.

This project is part of the QUEST initiative - Quantifying and Understanding the Earth System. The aim of QUEST is to improve understanding of large-scale processes and interactions in the whole Earth System, by modelling the three major components, ocean, land surface and atmosphere. The QUERCC project will address understanding and uncertainties in land surface processes, with particular emphasis on the carbon cycle. Land surface models are currently operational and the most suitable type for annual to decadal and century scale simulations are Dynamic Global Vegetation Models (DGVM). These simulate vegetation processes over the time scale from days to centuries. The representation of some processes are well validated, however some processes that are know to impact on the carbon cycle are either poorly represented or absent from some models. In such cases the different DGVMs that have been developed also differ in how these shortfalls in understanding are simulated. This project aims to compare different DGVMs within a simplified Earth System Model to see how they agree and differ in their responses to the changes in climate and atmospheric carbon dioxide concentration over the 20th century. The current state of the DGVMs will be compared initially against independent data sets. Activities in the project will provide modules of processes that are currently absent, or poorly represented in the DGVMs, and after integration in the DGVMs will be tested for their impacts on the simulations within the simplified Earth System Model. Key modules to be developed are for nutrient cycling, which exerts a major feedback on carbon exchange, a greater resolution of plant processes and the development of a global map of those plant functional types that exert significant impacts on the carbon cycle. At project completion key modules will have been evaluated and will be passed to the full Earth System Model programme for inclusion in the selected land surface scheme.