ORCA (Oregon and California)

Summary

Project Period: 09/01/04 - 08/31/07

PI:
B.E. Law, Ecology, Project Coordination

Co-PIs:
D. Turner, Modeling
W. Cohen, Remote sensing
J. Styles, Boundary layer model-data fusion

TERRA-PNW participants:
Tara Hudiburg, programmer
Zhiqiang Yang, Biome-BGC programmer
John Campbell, disturbance ecology
Dave Ritts, GIS/programmer
German Whitley, GIS
Mathias Goeckede, atmospheric programmer

OVERVIEW (Figure 1):

The project tests and demonstrates the bottom-up and top-down paradigm of the North American Carbon Program. To quantify and understand the carbon budgets of Oregon and northern California (Figure 2), a spatially nested hierarchy of field and satellite remote sensing observations is combined with a widely-used prognostic model of terrestrial carbon exchange (Biome-BGC) to implement a "bottom-up" approach that we previously tested in western OR coniferous forests. The "top-down" approach for regional and global applications uses a model-data fusion scheme to estimate monthly NEP and to partition it among gross primary production, autotrophic respiration, and heterotrophic respiration.
The approaches will be compared and evaluated to make improvements and provide critical understanding of major uncertainties about the carbon cycle. It will result in new understanding of important terrestrial carbon cycle processes, notably:

1. The effects of disturbance regimes, management, and land use on carbon stocks and fluxes in this region that is influenced by wildfire, logging, and urbanization.
2. The effects of interannual climate variation on carbon fluxes and the linkage between carbon and water fluxes across this seasonally drought affected region, and
3. The interactions between climate and disturbance across the large environmental gradient.

The relative magnitude of emissions and carbon sequestration will be investigated along a N-S gradient of anthropogenic carbon emissions. As part of the US-Italy bilateral, the top-down approach and a bottom-up approach is being applied in Italy. We will compare effectiveness of methods and synthesize results with a global perspective. Italy is a region with similar environmental and emissions gradients and seasonal drought, but substantially different land-use history and land-cover change.