Developing procedures to map stream spatial temperatures from thermal infrared imagesWe compare two methods for mapping stream temperature from thermal infrared imagery. The first method is an automated method that involves masking the "water" pixels in the thermal image and then estimating the local (image-derived) temperature as the median of the water pixels. The second method involves manual image sampling techniques.
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Assessment of future thermal regimes and the role of riparian vegetationThe cooling effects from the site potential riparian vegetation are likely to be offset by the climate change effects in the Wenatchee River by the 2020s. By the end of the century, assuming site potential shade, the tributaries could have a thermal condition similar to today’s condition which has less shade. Modeled increases in stream temperature due to global warming are determined primarily by the projected reductions in summer streamflows, and to a lesser extent by the increases in air temperature. The findings emphasize the importance of riparian vegetation restoration along the smaller tributaries, to prevent future temperature increases and preserve aquatic habitat. More...
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Use of thermal infrared imagery in monitoring and modeling stream temperaturesThermal infrared TIR surveys are effective methods to map surface spatial temperature patterns along a river. Detailed TIR images facilitate identifying regions with high local thermal heterogeneity where we recommend a weighted average approach to estimate local spatial average temperature using temperatures from pixels of the thermally distinctive areas rather than using the temperature extracted from pixels sampled along the central part of the channel. TIR-derived daily maximum temperatures complement monitoring and modeling of spatial stream temperatures. More...
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