Garratt Rachal ’20 is Using Infrared Thermography to Characterize Temperature Over Space and Time in Wisconsin Springs
Garrett Rachal is a Geology major and a 2020 graduate. He used infrared thermography to characterize temperature over space and time in Wisconsin springs.
Springs are known to create cold refuges for many aquatic biota during the summer, but little quantitative information is available on how temperature conditions vary among different spring types. Temperature differences between rheocrene fracture and seepage filtration springs can be spatially and temporally characterized to fill gaps in knowledge about their thermal heterogeneity. In this project, a FLIR Vue Pro R Thermal Camera captured thermal images of the top 0.1 µm of water in a fracture spring and a seepage filtration spring in late summer and early winter of 2019. The camera was mounted at a 90° angle directly above the springs to limit the effects of reflectivity and water disturbance on the thermal images. Emissivity is considered negligible due to the short observational distance (< 2 m). At two sites, one fracture and one seepage filtration spring, four static thermal images were taken, in addition to a 10-second sequence of images at one frame per second. The thermal images are assigned a consistent color palette assigned in the FLIR Tools software and have temperature ranges limited to highlight variation in temperature. Garrett’s goal in this project was to further understand processes of temperature within spring systems on a spatial and temporal basis and to fill in gaps of knowledge about thermal heterogeneity in time and space within Wisconsin’s spring systems. His thesis advisor is Sue Swanson.