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Enhancing the retrieval of stream surface temperature from Landsat data

Marti-Cardona, Belen, Prats, Jord and Niclòs, Raquel (2019) Enhancing the retrieval of stream surface temperature from Landsat data Remote Sensing of Environment, 224. pp. 182-191.

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2019_MartiCardonaetal_LandsatTemperatureMequinenza.pdf - Accepted version Manuscript
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Abstract

Thermal images of water bodies often show a radiance gradient perpendicular to the banks. This effect is frequently due to mixed land and water thermal pixels. In the case of the Landsat images, radiance mixing can also affect pure water pixels due the cubic convolution resampling of the native thermal measurements. Some authors recommended a general-purpose margin of two thermal pixels to the banks or a minimum river width of three pixels, to avoid near bank effects in water temperature retrievals. Given the relatively course spatial resolution of satellite thermal sensors, the three pixel margin severely restricts their application to temperature mapping in many rivers. This study proposes a new algorithm to enhance the retrieval of stream surface temperature using Landsat 8 thermal data, although it is also applicable to Landsat 7 and Landsat 5. The aim is not to perform a subpixel radiance unmixing but to refine the selection of unmixed, reliable pixels for temperature mapping. For this purpose, the spatial arrangement of native Landsat thermal pixels is approximated, and pure water pixels in the downscaled thermal band are selected accordingly. The least-favourable cubic convolution near-bank radiance mixing is simulated on image basis. Only pure thermal water pixels unaffected by the simulated worstcase resampling are selected. The algorithm allowed retrieving water surface temperature in reaches down to 120m wide, clearly improving the existing three pixel, i.e. 300m for Landsat 8, recommendation. The enhancing algorithm was applied to a reach in the Ebro River reach, Spain. It provided spatially distributed temperatures in narrow parts, upstream and downstream of a wide reservoir, offering new insight of the overall impact of the reservoir over the river thermal regime.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Civil and Environmental Engineering
Authors :
NameEmailORCID
Marti-Cardona, Belenb.marti-cardona@surrey.ac.uk
Prats, Jord
Niclòs, Raquel
Date : 15 February 2019
DOI : 10.1016/j.rse.2019.02.007
Copyright Disclaimer : © 2019 Elsevier Inc. All rights reserved.
Uncontrolled Keywords : River surface temperature; Landsat 8 thermal band; Thermal spatial resolution; Cubic convolution resampling; Thermal impact; Mequinenza reservoir; Ebro river; Thermal stratification
Depositing User : Diane Maxfield
Date Deposited : 01 Mar 2019 10:10
Last Modified : 01 Mar 2019 10:10
URI: http://epubs.surrey.ac.uk/id/eprint/850592

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