| Research concerning spatially-based models of energy and water balance, which relate landform to fundamental physical and biological processes, is among the frontiers of landscape ecology, and has implications for a broad spectrum of disciplines. Incoming solar radiation (insolation) is among the primary driving forces for the earth's physical and biological systems. While the physical processes that determine insolation are well understood and detailed studies have been performed for specific locations, extending site-specific models to larger scales is challenging. This dissertation has three primary goals: (1) to develop a spatially-based insolation model that facilitates basic and applied research concerning physical and biological processes at a landscape scale; (2) to examine spatial and temporal patterns of insolation at landscape scales for a topographically diverse study area in the Rocky Mountains, so as to gain a comprehensive and systematic understanding of topographic influences on insolation; and (3) to explore the importance of insolation in microclimate, and where appropriate, to incorporate insolation submodels that improve existing microclimate models.; First, I developed two comprehensive insolation modeling tools, TopoView (a standalone software program) and the Solar Analyst (an ArcView GIS extension), based on an upward-looking hemispherical viewshed algorithm. These tools calculate insolation maps using digital elevation models (DEMs) for input. Highly optimized algorithms account for the influences of sky obstruction, surface orientation, elevation, and atmospheric conditions. TopoView and the Solar Analyst provide convenient and effective tools for understanding spatial and temporal variation of insolation at landscape and local scales.; Finally, I evaluated the importance of insolation for microclimate, and used an insolation submodel to improve existing topoclimatic models.; The ability to produce accurate insolation maps, with high temporal and spatial resolution, and based on readily available DEMS, presents a valuable addition to the tools available for study of landscape ecology. By understanding fundamental relationships between landform and spatial and temporal variation of insolation at the earth's surface, the research presented herein greatly improves our ability to predict landscape patterns of energy and water balance, microclimate, and dynamical changes of key habitat factors for terrestrial organisms. (Abstract shortened by UMI.)... |
