Changes in turbidity and human activities along Haihe River Basin during lockdown of COVID-19 using satellite data

• Published in: Environmental science and pollution research international 2022-01, Vol.29 (3), p.3702-3717
• Main Authors: Chen, Xu, Chen, Wei, Bai, Yanbing, Wen, Xiaole
• Format: Article
• Language: English
• Subjects: Anthropogenic Effects; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; China; Communicable Disease Control; Coronaviruses; COVID-19; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental Monitoring; Environmental science; Human influences; Infrared analysis; Natural environment; Public health; Research Article; River basins; Rivers; Satellite Imagery; Turbidity; Urban areas; Urban environments; Viral diseases; Waste Water Technology; Water Management; Water Pollution Control; Water quality
• ISSN: 0944-1344; 1614-7499; 1614-7499
• DOI: 10.1007/s11356-021-15928-6

During the outbreak of the COVID-19, China implemented an urban lockdown in the first period. These measures not only effectively curbed the spread of the virus but also brought a positive impact on the ecological environment. The water quality of urban inland river has a significant impact on urban ecology and public health. This study uses Sentinel-2 visible and near-infrared band reflectance and the Normalized Difference Turbidity Index (NDTI) to analyze the water quality of the Haihe River Basin during the control period of COVID-19. It is found that during the lockdown period, the river water quality was significantly improved compared to the same period in 2019. The average NDTI of the Haihe River Basin in March decreased by 0.27, a decrease of 219.06%; in April, it increased by 0.07, that is 38.38%. Further exploration using VIIRS lights found that the brightness of the lights in the main urban area was significantly lower in February, the beginning of the lockdown. However, as the city was unblocked, the lights rose sharply in March and then recovered to normal. There is obvious asynchrony in changes between river turbidity and light. The results can help understand the impact of human activities on the natural environment.