Can Landsat Thermal Imagery and Environmental Data Accurately Estimate Water Temperatures in Small Streams?

Abstract

The ability to monitor water temperature is important for assessing changes in riverine ecosystems resulting from climate warming. Direct in situ water temperature collection efforts provide point-samples but are cost-prohibitive for characterizing stream temperatures across large spatial scales, especially for small, remote streams. In contrast, satellite thermal infrared imagery may provide a spatially extensive means of monitoring riverine water temperatures, however, the accuracy of these remotely sensed temperatures for small streams is not well understood. Here, we investigated the utility of Landsat 8 thermal infrared imagery and both local and regional environmental variables to estimate subsurface temperatures in high latitude small streams (2 – 30 m wetted width), from a test watershed in southcentral Alaska. Our results suggested that Landsat-based surface temperatures were biased high, and the degree of bias varied with hydrological and meteorological factors. However, with limited in-stream validation work, results indicated it is possible to reconstruct average in situ water temperatures for small streams at regional-scales using a regression modelling framework coupled with publicly-available Landsat or air temperature information. Generalized additive models built from stream stage information from a single gage and air temperatures from a single weather station in the drainage fit to a limited set of in situ temperature recordings could estimate average stream temperatures at the watershed-level with reasonable accuracy (root mean square error = 2.4°C). Landsat information did track closely with regional air temperatures and could also be incorporated into a regression model as a substitute for air temperature to estimate in situ stream temperatures at watershed scales. Importantly, however, while average watershed-scale stream temperatures may be predictable, site-level estimates did not improve with the use of Landsat information or other local covariates, indicating that additional information may be necessary to generate accurate spatially explicit temperature predictions for small order streams.

Fisheries Volume 48 Number 7 July 2023

“…Due to the expansive network of streams in the Arctic, funding the development of virtual watershed data sets (i.e., Netmap; Benda et al 2007 ; www.terra inwor ks.com ) created from existing high-resolution digital terrain model data (i.e., interferometric synthetic aperture radar elevation data) offer a scalable solution to accurately quantify stream extent and channel habitat types (See Leppi et al 2022a ) and would provide needed information to understand climate impacts to fi sh habitat. Additionally, if funded, projects that use satellite imagery to develop stream temperature models (e.g., Handcock et al 2006 ;Wawrzyniak et al 2012 ;Murphy et al 2021 ) offer potential solutions to developing accurate and spatially continuous stream temperature estimates across the Arctic. Currently, information from fi ne-scale temperature models to project changes in the extent and distribution of thermally suitable freshwater, estuarine, and marine habitat remains a gap for the Arctic.…”

Climate Change Risks to Freshwater Subsistence Fisheries in Arctic Alaska: Insights and Uncertainty from Broad Whitefish Coregonus nasus

“…Due to the expansive network of streams in the Arctic, funding the development of virtual watershed data sets (i.e., Netmap; Benda et al 2007; http://www.terrainworks.com) created from existing high‐resolution digital terrain model data (i.e., interferometric synthetic aperture radar elevation data) offer a scalable solution to accurately quantify stream extent and channel habitat types (See Leppi et al 2022a) and would provide needed information to understand climate impacts to fish habitat. Additionally, if funded, projects that use satellite imagery to develop stream temperature models (e.g., Handcock et al 2006; Wawrzyniak et al 2012; Murphy et al 2021) offer potential solutions to developing accurate and spatially continuous stream temperature estimates across the Arctic. Currently, information from fine‐scale temperature models to project changes in the extent and distribution of thermally suitable freshwater, estuarine, and marine habitat remains a gap for the Arctic.…”

Applying High-Resolution Satellite and UAS Imagery for Detecting Coldwater Inputs in Temperate Streams of the Iowa Driftless Region

“…In particular, orbital satellite sensors acquiring imagery in the thermal infrared (TIR) wavelength of the electromagnetic spectrum have been used to map stream temperatures [16,17]. While satellite-acquired thermal imagery is able to map temperatures of wider streams (i.e., stream width > 100 m) [18][19][20], its effectiveness for monitoring narrower streams is limited due to coarse spatial resolution (i.e., pixel size > 50 m) [21,22]. Additionally, orbital sensors are less sensitive to fine-scale variation in water temperature and their magnitude of error could be relatively high, making accurate temperature mapping challenging [23].…”