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Quantification of Spatial and Temporal Variability of North American Biospheric Carbon Flux Estimates

Deborah N. Huntzinger, University of Michigan, dnhuntzi@umich.edu (Presenting)
Kim L. Mueller, University of Michigan, kimlm@umich.edu
Anna M. Michalak, University of Michigan, amichala@umich.edu

A number of biospheric or processed-based models have been developed to estimate the magnitude of carbon sources and sinks across regional and continental scales. These models vary in complexity and tend to include a diverse array of processes that operate on widely different spatial and temporal scales. Both the complexity of the system being modeled, as well as the inherent differences among the various modeling approaches make it difficult to ascertain which environmental and ecosystem drivers most strongly control carbon exchange and at what scale these drivers operate. This study presents a formal inter-comparison of several biospheric models, using geostatistical structural analysis tools to examine the spatial variability in predicted fluxes from three biospheric models that range in complexity from simple (VPRM) to more complex (CASA, SiB3) from 2002 through 2004. The results of the analysis indicate that the models have significantly different spatial correlation lengths and degrees of variability when compared at the regional or continental scale. CASA and SiB both appear to show relatively constant correlation lengths across months, while correlation lengths in VPRM vary over the course of the year, with shorter correlation lengths and greater variances during the growing season, compared to colder months. Potential source of both model-model and model-data mismatch are addressed through a systematic analysis of the influence of model drivers through each model&rsquos formulation, as well as through an examination of whether the model&rsquos spatial variability has a quantifiable influence on the model&rsquos predictive capabilities.


NASA Carbon Cycle & Ecosystems Active Awards Represented by this Poster:

  • Award: NNX06AE84G
    Start Date: 2006-09-01
     

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