DOI: 10.5066/p1nyeecn
title: Airborne Thermal Infrared and True-color Imagery and Longitudinal Profiles of Stream Temperatures, Santiam River Basin, Oregon, August 2000

description: This dataset includes high-resolution thermal infrared (TIR) and true-color images collected from crewed aircraft and a point shapefile and corresponding comma-delimited tabular data representing the longitudinal spatial patterns of surface water temperature in the surveyed streams in the Santiam River Basin, Oregon. The aerial surveys were contracted through Watershed Sciences, LLC by the Oregon Department of Environmental Quality. The TIR and true-color images were collected with an AGEMA Infrared Systems, Thermovision 1000 forward-looking infrared (FLIR) imager and a video camera on a gyro-stabilized mount attached to a helicopter. Surveys of 227 kilometers (km) in 25 streams within the North and South Santiam River basins were conducted on August 1-3, 2000 in the afternoon (13:00-17:00 PDT) under warm seasonal conditions. The daily air temperature on the survey dates at Cascadia State Park (244 meters (m) elevation; https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?or1433) ranged from 10 to 27 degrees Celsius (C). Individual ungeoreferenced TIR image frames are provided in tag image file format (TIFF) and true-color image frames are provided in joint photographic experts group (JPEG) format with approximate ground resolutions ranging from 0.25-0.50 m. A raster mosaic TIFF of TIR images for the survey of the main stem of Quartzville Creek (8.9 km) is included to illustrate spatially continuous patterns of stream temperature for this survey reach. The TIR mosaic was created from individual image frames that were georeferenced and rectified manually because the technology for precise in-flight recording of camera orientation and photogrammetric data was not available for the TIR imager and true-color video camera in the year 2000. The TIR rasters contain corrected radiant surface temperatures in degrees C (multiplied by 10 to create an unsigned integer pixel type). The radiant temperatures derived from the TIR rasters were calibrated with kinetic temperatures from 26 in-stream data loggers positioned where water velocity was sufficient for vertical mixing; the TIR imagery met the contract-specified accuracy of ±0.5°C difference between the FLIR image and the in-stream data logger. The longitudinal stream temperatures are in degrees C and are provided in geospatial format (i.e., point shapefiles [.shp] modified in ESRI ArcGIS Pro 3.4) and in a comma-separated value (CSV) tabular format. The true-color image frames are not available for all surveyed rivers and streams due to degradation of the media on which they were initially stored. The shapefile point features spaced along the survey flight paths approximately every 25-100 m were linearly referenced with respect to their distance upstream in river km using Arc/Info geographic information system (GIS) software based on “routed” 1:100,000-scale hydrography from the U.S. Environmental Protection Agency (EPA) River Reach File Version 3.0 hydrographic database of surface waters (https://archive.epa.gov/esd/archive-nerl-esd1/web/html/nvgeo_gis10_rf3_md.html). Stream temperature statistics in the shapefiles and tabular data were derived by manually selecting and sampling pure-water pixels in each TIR image frame with a semi-automated Avenue script in ESRI ArcView GIS 3.1 along the main channel of each stream reach. Longitudinal stream temperature profiles (i.e., median temperature versus distance upstream) can be produced by plotting the tabular data with graphing software.