| An environmental model is a simplified representation of a phenomenon, process, or system that occurs in natural environments. Geographic information system (GIS) is a computer based system capable of representing and analyzing geospatial features and processes. This dissertation focuses on developments of environmental models coupled with GIS, and environmental analyses using the developed systems.;Hydrologic regional regression models were loosely coupled with GIS to seamlessly exchange data within these two systems. The coupled system automated the derivation of watershed characteristics from approximately 1500 raster datasets for flood and low streamflow regional regression model constructions. The effectiveness and efficiency of the developed system was estimated and discussed. Using the developed system, watershed characteristics for more than 100 various sized watersheds were derived with 80 raster datasets. The appropriate Digital Elevation Model (DEM) horizontal resolution for delineating watershed boundaries was determined based on the watershed size and the horizontal resolution of the DEM and raster dataset.;Air quality models and GIS were tightly coupled with a component-based approach. This effort involved developing lumped and distributed dry deposition models, identifying important model parameters via sensitivity analyses, and integrating the distributed model with GIS. Using the lumped model, dry deposition of air pollutants were quantified for Baltimore, MD in 2005. Two sensitivity analyses performed for the lumped model identified temperature and leaf area index (LAI) as particularly influential to model output. These two parameters and ambient air pollutant concentrations, which directly impact dry deposition amounts, were estimated in a spatially distributed form for the coupled system. Using this system, spatial patterns of temperature, LAI, air pollutant concentrations, air pollutant transportation resistances, dry deposition velocity, and flux of nitrogen dioxide (NO2) were examined. Based on these results, potential areas for future urban forest planting to improve air quality in Baltimore were identified.;Through the developments of model and GIS coupled systems, efficiency of data extraction, data interpretability, and model reusability and interoperability were validated. A component-based modeling approach enabled rapid, effective, and reliable coupling of environmental models and GIS, while keeping the integrity and security of original source codes intact.;Keywords: hydrologic model, air quality model, dry deposition, air pollutant dispersion, geographic information system, model and GIS coupling, component-based approach, lumped model, distributed model. |
