AIRBORNE RECONNAISSANCE OF HYDROTHERMAL AREAS USING DAYTIME THERMAL INFRARED IMAGERY

We use temperature data from oblique airborne Forward-Looking InfraRed (FLIR) images to calculate heat flow values of various hydrothermal features in Yellowstone National Park, WY. The method developed relies on knowing the position at which the FLIR image was taken and the position of the feature being observed and does not require any field data. This allows for cost-effective, rapid reconnaissance of a thermal area where a FLIR camera can be taken on a helicopter or small aircraft and flown over the region of interest. The thermal images can be analyzed in a matter of hours after the flight to obtain heat flow and total heat output data of the thermal features. This method has advantages over other airborne thermal imaging techniques because it allows for frequent observations, a focus on specific thermal features, and field verification of the observations. Flights can be requested and flown whenever needed over any thermal feature. Field checking temperatures and dimensions of hydrothermal features can confirm the accuracy of the FLIR images and heat flow calculations. Precise replication of previous flight paths also is not required, further enabling the ease of repeated measurements of a thermal feature for change detection. While not as accurate as ortho-rectified satellite or airborne thermal imagery, this method provides a low-cost, frequent manner to quantify thermal features. The application of this method can contribute to the monitoring a geothermal system like Yellowstone National Park.