Thermal remote sensing with an autonomous unmanned aerial remote sensing platform for surface stream temperatures

Stream temperature is important for understanding the environment within a stream. Many collect these data at discrete locations over specific time periods using temperature sensors, however it is becoming more common to gather thermal imagery to have a spatially distributed understanding. The utility of these data can be limited due to cost, and spatial and temporal resolutions. This paper presents a platform for low-cost high-resolution thermal imagery using an unmanned aerial vehicle (AggieAir¹). AggieAir can be used to acquire visual, near-infrared (NIR), and thermal imagery at high spatial and temporal resolutions at a much lower cost when compared to conventional sources of remote sensing. In this application, AggieAir is used to collect visual, NIR, and thermal imagery for a stream in northern Utah. Details about the payload and postprocessing methods are presented. The resulting imagery was used to clip the thermal mosaic to only include pixels associated with the stream. This thermal image provided 30cm×30cm resolution stream temperatures. Finally, a simple method of adjusting the images to observed temperatures is proposed to provide better information regarding absolute stream temperatures which are key in understanding the health of the aquatic ecosystem.