Development of accurate, computationally efficient simulation models for hydrologic processes and vegetation is needed for use in global climate models. Methods for validating such models need to be broader in scope and easier to implement on various time and length scales. The objective of this study is to develop and test a watershed simulation model which includes simulation of the response of vegetation to changing hydrologic conditions. An important objective of this study is to find out whether the hydrologic status of watersheds can be assessed accurately by using remote sensing observations of vegetation and simulation models. Our approach involves development of a watershed simulation model which integrates existing ground-based, airborne, and satellite observations of a watershed in the Uinta Mountains. The vegetaton distribution will be based on the U.S. Fish and Wildlife Service's digital vegetation database. The model will be used to simulate the response of vegetation (i.e., transpiration, assimilation, leaf growth the abcission) to environmental conditions and model values of soil moisture, soil temperature, streamflow, transpiration, surface temperature, leaf area, and assimilation will be compared to measured values. We will make new field measurements of soil moisture, temperature, transpiration, and photosynthesis. We will also use operational meteorological and hydrologic data for model initialization and validation. Finally, the sensitivity of predictions to model parameters will be investigated.
