A practitioner's guide to thermal infrared remote sensing of rivers and streams: recent advances, precautions and considerations

Stream temperature is a key habitat variable controlling all physical and biological river processes. In light of the threat of climate change to fluvial environments, growing importance is being placed on the need to gain a better understanding of stream temperature dynamics. However, many current or historic stream temperature datasets are of very low spatial resolution. Such in situ measurements are often unable to provide the fine scale information on longitudinal or lateral temperature patterns necessary for understanding links between thermal heterogeneity and fluvial processes. In recent years, attention has therefore turned to the use of thermal infrared (TIR) remote sensing in order to acquire 2D stream temperature data at ecologically meaningful scales. While TIR remote sensing is a relatively mature technology in its own right, its application in fluvial environments is accompanied by a range of limitations and considerations that must be respected in order to ensure the acquisition of reasonable quality data. It is only in recent years that researchers have been started to shift from detailing the technical aspects of TIR imaging of river environments toward describing its application for river management and fundamental fluvial science. We critically review this recent research, demonstrating the utility of TIR for applied river temperature research. We also provide a detailed guide to the practical use of TIR in river environments with a view to further stimulating its use for advancing stream temperature science. WIREs Water 2016, 3:251–268. doi: 10.1002/wat2.113