Heat Budget Monitoring in Norris Geyser Basin, Yellowstone National Park

Abstract:

Frequent estimation of heat flux in active hydrothermal areas are required to monitor the variation in activity. Natural changes in geothermal and hydrothermal features can include rapid significant changes in surface temperature distribution and may be an indication of “re-plumbing” of the systems or potential hydrothermal explosions. Frequent monitoring of these systems can help Park managers make informed decisions on infrastructure development and/or take precautionary actions to protect the public.

Norris Geyser Basin (NGB) is one of Yellowstone National Park’s hottest and most dynamic basins. Airborne high-resolution thermal infrared remote sensing was used to estimate radiometric temperatures within NGB and allow for the estimation of the spatial and temporal distribution of surface temperatures and the heat flow budget. The airborne monitoring occurred in consecutive years 2008-2012 allowing for the temporal comparison of heat budget in NGB. Airborne thermal infrared images in the 8-12 µm bands with 1-m resolution were acquired using a FLIR SC640 scanner. Digital multispectral images in the green (0.57 µm), red (0.65 µm), and near infrared (0.80 µm) bands were also acquired to classify the terrain cover and support the atmospheric and emissivity correction of the thermal images.

The airborne images were taken in the month of September on selected days with similar weather and under clear sky conditions. In the winter of 2012, images were also taken in March to compare the effect of the cold weather and snow cover on the heat budget. Consistent methods were used to acquire and process the images each year to limit the potential variability in the results to only the variability in the hydrothermal system. Data from radiation flux towers installed within the basin were used to compare with airborne radiometric surface temperatures and compensate for residual solar heating in the imagery.

The presentation will discuss the different mechanisms involved in determining the heat budget i.e. convection heat, radiation heat, and latent heat through the evaporation of water and show preliminary estimates of heat fluxes for the entire basin.