The overall topic of the research described in this dissertation was theudpartitioning of available energy at the Earth's surface into sensible and latent heatudflux, with an emphasis on the development of techniques which utilize remotelyudsensed data. One of the major objectives was to investigate the modification ofudexisting techniques, developed over agricultural surfaces, to "natural" ecosystems (i.e.,udnon -agricultural vegetation types with variable and incomplete canopy cover).udGround -based measurements of surface fluxes, vegetation cover, and surfaceudand root -zone soil moisture from the First ISLSCP (International Land SurfaceudClimatology Program) Field Experiment (FIFE) were used to examine the factorsudcontrolling the partitioning of energy at ground stations with contrasting surfaceudcharacteristics.udUtilizing helicopter -based and satellite -based data acquired directly overudground -based flux stations at the FINE experimental area, relatively simpleudalgorithms were developed for estimating the soil heat flux and sensible heat fluxudfrom remotely sensed data. The root mean square error (RMSE) between theudsensible heat flux computed with the remotely sensed data and the sensible heat fluxudmeasured at the ground stations was 33 Wm 2. These algorithms were then appliedudon a pixel -by -pixel basis to data from a Landsat -TM (Thematic Mapper) sceneudacquired over the FIFE site on August 15, 1987 to produce spatially distributedudsurface energy- balance components for the FIFE site.udA methodology for quantifying the effect of spatial scaling on parametersudderived from remotely sensed data was presented. As an example of the utility of this approach, NDVI values for the 1,IFE experimental area were computed withudinput data of variable spatial resolution. The differences in the values of NDVIudcomputed at different spatial resolutions were accurately predicted by an equationudwhich quantified those differences in terms of variability in input observations.
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