Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared Images
Dams play a significant role in altering the spatial pattern of temperature in rivers and contribute to thermal pollution, which greatly affects the river aquatic ecosystems. Understanding the temporal and spatial variation of thermal pollution caused by dams is important to prevent or mitigate its...
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doaj-3bc647ea9c534498a28ae911304ab11e2020-11-25T02:43:10ZengMDPI AGRemote Sensing2072-42922017-11-01911117510.3390/rs9111175rs9111175Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared ImagesFeng Ling0Giles M. Foody1Hao Du2Xuan Ban3Xiaodong Li4Yihang Zhang5Yun Du6Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, ChinaSchool of Geography, University of Nottingham, University Park, Nottingham NG7 2RD, UKYangtze River Fisheries Research Institute, Chinese Academy of Fishery Science, Jingzhou 434000, ChinaInstitute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, ChinaInstitute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, ChinaInstitute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, ChinaInstitute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, ChinaDams play a significant role in altering the spatial pattern of temperature in rivers and contribute to thermal pollution, which greatly affects the river aquatic ecosystems. Understanding the temporal and spatial variation of thermal pollution caused by dams is important to prevent or mitigate its harmful effect. Assessments based on in-situ measurements are often limited in practice because of the inaccessibility of water temperature records and the scarcity of gauges along rivers. By contrast, thermal infrared remote sensing provides an alternative approach to monitor thermal pollution downstream of dams in large rivers, because it can cover a large area and observe the same zone repeatedly. In this study, Landsat Enhanced Thematic Mapper Plus (ETM+) thermal infrared imagery were applied to assess the thermal pollution caused by two dams, the Geheyan Dam and the Gaobazhou Dam, located on the Qingjiang River, a tributary of the Yangtze River downstream of the Three Gorges Reservoir in Central China. The spatial and temporal characteristics of thermal pollution were analyzed with water temperatures estimated from 54 cloud-free Landsat ETM+ scenes acquired in the period from 2000 to 2014. The results show that water temperatures downstream of both dams are much cooler than those upstream of both dams in summer, and the water temperature remains stable along the river in winter, showing evident characteristic of the thermal pollution caused by dams. The area affected by the Geheyan Dam reaches beyond 20 km along the downstream river, and that affected by the Gaobazhou Dam extends beyond the point where the Qingjiang River enters the Yangtze River. Considering the long time series and global coverage of Landsat ETM+ imagery, the proposed technique in the current study provides a promising method for globally monitoring the thermal pollution caused by dams in large rivers.https://www.mdpi.com/2072-4292/9/11/1175damthermal pollutionremote sensingLandsatwater temperaturethermal infrared image |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Feng Ling Giles M. Foody Hao Du Xuan Ban Xiaodong Li Yihang Zhang Yun Du |
spellingShingle |
Feng Ling Giles M. Foody Hao Du Xuan Ban Xiaodong Li Yihang Zhang Yun Du Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared Images Remote Sensing dam thermal pollution remote sensing Landsat water temperature thermal infrared image |
author_facet |
Feng Ling Giles M. Foody Hao Du Xuan Ban Xiaodong Li Yihang Zhang Yun Du |
author_sort |
Feng Ling |
title |
Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared Images |
title_short |
Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared Images |
title_full |
Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared Images |
title_fullStr |
Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared Images |
title_full_unstemmed |
Monitoring Thermal Pollution in Rivers Downstream of Dams with Landsat ETM+ Thermal Infrared Images |
title_sort |
monitoring thermal pollution in rivers downstream of dams with landsat etm+ thermal infrared images |
publisher |
MDPI AG |
series |
Remote Sensing |
issn |
2072-4292 |
publishDate |
2017-11-01 |
description |
Dams play a significant role in altering the spatial pattern of temperature in rivers and contribute to thermal pollution, which greatly affects the river aquatic ecosystems. Understanding the temporal and spatial variation of thermal pollution caused by dams is important to prevent or mitigate its harmful effect. Assessments based on in-situ measurements are often limited in practice because of the inaccessibility of water temperature records and the scarcity of gauges along rivers. By contrast, thermal infrared remote sensing provides an alternative approach to monitor thermal pollution downstream of dams in large rivers, because it can cover a large area and observe the same zone repeatedly. In this study, Landsat Enhanced Thematic Mapper Plus (ETM+) thermal infrared imagery were applied to assess the thermal pollution caused by two dams, the Geheyan Dam and the Gaobazhou Dam, located on the Qingjiang River, a tributary of the Yangtze River downstream of the Three Gorges Reservoir in Central China. The spatial and temporal characteristics of thermal pollution were analyzed with water temperatures estimated from 54 cloud-free Landsat ETM+ scenes acquired in the period from 2000 to 2014. The results show that water temperatures downstream of both dams are much cooler than those upstream of both dams in summer, and the water temperature remains stable along the river in winter, showing evident characteristic of the thermal pollution caused by dams. The area affected by the Geheyan Dam reaches beyond 20 km along the downstream river, and that affected by the Gaobazhou Dam extends beyond the point where the Qingjiang River enters the Yangtze River. Considering the long time series and global coverage of Landsat ETM+ imagery, the proposed technique in the current study provides a promising method for globally monitoring the thermal pollution caused by dams in large rivers. |
topic |
dam thermal pollution remote sensing Landsat water temperature thermal infrared image |
url |
https://www.mdpi.com/2072-4292/9/11/1175 |
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