A Study of Spatial and Temporal Mass and Heat Transport of Hydrothermal Features in Norris Geyser Basin, Yellowstone National Park
Monitoring the dynamic thermal activity in Yellowstone National Park is required by the United States Congress. The continuous monitoring is important to maintain the safety of the visitors and park service personnel, plan and relocate infrastructure, and study potential impact from nearby geothermal development including oil and gas industry. This dissertation is part of a study initiated in the early 2000s to monitor the thermal activity of dynamic areas within the Park, using airborne remote sensing imagery. This study was focused in Norris Geyser Basin, the hottest geyser basin in the park, located near the northwestern rim of the Yellowstone’s caldera. The study is considered the first long-term comprehensive airborne remote sensing study in the basin which took place between August 2008 and October 2013. In this study, at least one 1-meter resolution thermal infrared image and three-band images (multispectral) were acquired and used to estimate year-to-year changes in radiant temperature, radiant flux, and radiant power from the thermal source in Norris.
Presence of residual radiant flux in the ground from absorbed solar radiation and atmospheric longwave radiation was the main challenge to compare year-to-year changes in the thermal activity. This residual flux is included in the total radiant flux calculated through the remote sensing images which gives false estimates of the flux generated from the underling thermal source. Two methods were suggested in Chapters 2 and 4 of this dissertation to estimate the residual radiant flux. A method was developed in Chapter 2 to estimate the residual radiant flux in a bare ground area covered with hydrothermal siliceous sinter deposit. The method compared ground-based measurements with high spatial resolution airborne remote sensing measurements to estimate the residual radiant flux. In Chapter 4, a method was developed to estimate the residual radiant flux in the six surface classes in Norris, including bare ground, bare ground with siliceous sinter deposit, lakes and pools, river, forest, and grass. The assumptions and implications of each method were discussed to suggest a reliable method to estimate the geothermal radiant flux after subtracting the absorbed residual radiant flux. Chapter 3 provides an analysis of the four components of heat flux in the ground surface, including conduction of sensible heat, convection of sensible heat by liquid water and water vapor, and convection of latent heat by water vapor. The main purpose from the analysis was to assess the hypothesis that the convection and latent heat flux are negligible which therefore supported the results obtained from the analysis in Chapters 2 and 4.