@prefix ns0: . @prefix skos: . ns0:altLabel [ ] ; skos:broader ; skos:prefLabel "FED MAC"@en ; skos:inScheme ; skos:definition """The Biospheric Sciences Branch (formerly Earth Resources Branch) within the Laboratory for Terrestrial Physics at NASA's Goddard Space Flight Center and associated University investigators are involved in a research program entitled Forest Ecosystem Dynamics (FED) which is fundamentally concerned with vegetation change of forest ecosystems at local to regional spatial scales (100 to 10,000 meters) and temporal scales ranging from monthly to decadal periods (10 to 100 years). The nature and extent of the impacts of these changes, as well as the feedbacks to global climate, may be addressed through modeling the interactions of the vegetation, soil, and energy components of the boreal ecosystem. The FED ecosystem modeling research efforts concentrate on the North American boreal and northern hardwood transition forests with emphasis on optical and radar remote sensing technology. This research employs an integrated approach of field and aircraft studies, theoretical modeling, and satellite image data processing to infer where landscape pattern and process ecosystem model predictions succeed or fail at regional spatial scales and interannual temporal scales. We are also using remote sensing observations as a check on potentially observable forest ecosystem model predicted attributes (e.g., species composition, tree height distributions, land use patterns). Conversely, we are investigating the potential of remote sensing observations for extracting biophysical properties of forest canopies, soils, and hydrologic parameters used in our forest ecosystem models. On-going work, in addition to activities discussed here, include modeling, measurement, and data compilation or a number of boreal zone sites. The FED model framework (see Levine et al., 1983) integrates existing models of forest growth and succession (i.e., FORET model of Shugart and West, 1984 and ZELIG Model of Smith and Urban, 1988), soil processes (Residue model of Bidlake et al., 1992; Bristow, et al., 1986; TERRA model of Levine, 1984; Levine and Ciolkosz, 1988), and energy dynamics (e.g., Smith et. al., 1981; Kimes and Kirchner, 1982). Each of the models interact with the others to provide feedback controls on growth, soil related processes, and energy internal and external to the forest environment. The forest succession and soil process models require input at the species and soil characteristics level, respectively. This makes this formulation useful for examining the effects of changes in climate or anthropogenic factors on the community composition and structure of the boreal forest. The results anticipated from this experiment will enable development and validation of the integrated model to usefully characterize the ecosystem dynamics of the boreal forest under a variety of conditions. A number of questions pertinent to the combined experiment may then be considered. For example, how do climatic gradients determine the spatial distribution of species within the boreal forest? What are the possible effects of global climate change on the boreal forest? Is the boreal forest a net source or sink of carbon and methane and will the present state change if climate changes? Also relevant to the issue of global change are the magnitudes of the feedbacks between climate and vegetation. The model, as formulated, can provide insights into the effects of climate change on ecosystem dynamics, but does not consider the effects of ecosystem changes on climate directly. However, the model can provide, as outputs, factors that impact climate such as albedo, evapotranspiration, and trace gas fluxes (i.e., carbon dioxide, methane, and nitrogen). These questions are also relevant to the BOREAS experiment. The overall objective of our work was to capitalize on and develop the unique advantages of remote sensing data combined with models of forest ecosystem dynamics for characterizing northern/boreal forest ecosystems, especially with regard to the interpretation of landscape patterns and processes at local and regional scales. Specific objectives for the FED experiment at IP's Northern Experimental Forest included: 1. Enhance the development of an integrated quantitative model which simulates forest, soil, and energy dynamics processes in northern forest environments. This will be achieved through modification and continuing development of the three types of sub-models discussed above. 2. Develop improved remote sensing technology to infer biophysical parameter inputs for forest succession and soil models. The relationships among remote sensing and forest canopy characteristics required by forest succession and soil process models will be developed and tested. 3. Develop a better understanding of the transfer and utilization of energy in forest canopies. This goal is being accomplished via collection of detailed spectral reflectance data in the field and laboratory, and by exercising existing radiative transfer models. 4. Use field and remote sensing observations to help infer where landscape pattern and process ecosystem models succeed or fail at local to regional spatial scales and interannual temporal scales. This objective is being accomplished through comparison of model predictions with field experimental data, and changes in successional stage, bioproductivity, and other biophysical parameters based on remotely sensed measurements. 5. Use field and remote sensing observations to help infer where landscape pattern and process ecosystem models succeed or fail at local to regional spatial scales and interannual temporal scales. This objective is being accomplished through comparison of model predictions with field experimental data, and changes in successional stage, bioproductivity, and other biophysical parameters based on remotely sensed measurements. 6. Use remote sensing observations as a check on such potentially observable forest ecosystem dynamic model predicted attributes. Specific ecosystem model algorithms and output parameters are being evaluated directly by examining relationships developed between sensor measured response and ecosystem attributes. 7. Use remote sensing observations and models to extract biophysical properties of forest canopies, soils, and hydrologic parameters used in our forest ecosystem models. Physically based radar and optical models are being applied to data collected over subsets of the Northern Experimental Forest to examine radar and optical scattering characteristics of different scene components. Model inversion strategies are also being applied for selected ecosystem model inputs. For more information, link to "http://forest.gsfc.nasa.gov/html/fedmac/fedmac.html\""""@en ; a skos:Concept . skos:prefLabel "D - F"@en ; a skos:Concept ; skos:narrower .