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Ground‐based thermography of fluvial systems at low and high discharge reveals potential complex thermal heterogeneity driven by flow variation and bioroughness
Author(s) -
Cardenas M. Bayani,
Harvey Judson W.,
Packman Aaron I.,
Scott Durelle T.
Publication year - 2008
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.6932
Subject(s) - environmental science , periphyton , fluvial , thermography , hydrology (agriculture) , thermal , biogeochemical cycle , shoal , streams , sampling (signal processing) , spatial variability , base flow , flood myth , remote sensing , geology , infrared , geomorphology , meteorology , ecology , computer science , drainage basin , oceanography , geotechnical engineering , mathematics , filter (signal processing) , structural basin , geography , computer network , optics , biology , computer vision , biomass (ecology) , statistics , physics , cartography , philosophy , theology
Temperature is a primary physical and biogeochemical variable in aquatic systems. Field‐based measurement of temperature at discrete sampling points has revealed temperature variability in fluvial systems, but traditional techniques do not readily allow for synoptic sampling schemes that can address temperature‐related questions with broad, yet detailed, coverage. We present results of thermal infrared imaging at different stream discharge (base flow and peak flood) conditions using a handheld IR camera. Remotely sensed temperatures compare well with those measured with a digital thermometer. The thermal images show that periphyton, wood, and sandbars induce significant thermal heterogeneity during low stages. Moreover, the images indicate temperature variability within the periphyton community and within the partially submerged bars. The thermal heterogeneity was diminished during flood inundation, when the areas of more slowly moving water to the side of the stream differed in their temperature. The results have consequences for thermally sensitive hydroecological processes and implications for models of those processes, especially those that assume an effective stream temperature. Copyright © 2008 John Wiley & Sons, Ltd.