Retrieving the Lake Trophic Level Index with Landsat-8 Image by Atmospheric Parameter and RBF: A Case Study of Lakes in Wuhan, China

Zhou, Yadong; He, Baoyin; Xiao, Fei; Feng, Qi; Kou, Jiefeng; Liu, Hui

doi:10.3390/rs11040457

Cited by 16 publications

(7 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Image filtering is a remote-sensing image-enhancement method, which redistributes the mathematical calculations of surrounding pixels to the central pixel. Filtering before extracting water can eliminate non-water pixels, such as boats and bridges on the water surface [30]. The NDWI, which typically ranges from −1 to 1, is an important metric for identifying water features in an image.…”

Section: Sentinel-2 Data and Processingmentioning

confidence: 99%

Monitoring Total Phosphorus Concentration in the Middle Reaches of the Yangtze River Using Sentinel-2 Satellites

Yang,

Feng,

Zhou

et al. 2024

Remote Sensing

Self Cite

View full text Add to dashboard Cite

Total phosphorus (TP, a non-optical sensitivity parameter) has become the primary pollutant in the Yangtze River, the third largest river in the world. It is strongly correlated with turbidity (an optical sensitivity parameter) in rivers. In this study, we constructed a turbidity-mediated TP retrieval model using Sentinel-2 observations and field-measured daily-scale water quality. The model was successfully applied to estimate the temporal and spatial variations of TP concentration in the middle reaches of the Yangtze River (MYR) from 2020 to 2023. Our results show: (1) the model accuracy of TP concentration retrieval with turbidity is significantly higher (R2 = 0.71, MAPE = 15.78%) than that for the model without turbidity (R2 = 0.62, MAPE = 16.38%); (2) the turbidity and TP concentration in the MYR is higher in summer and autumn than in winter and spring; and (3) the turbidity and total phosphorus (TP) concentration of the Yangtze River showed a significant increase after passing through Dongting Lake (p < 0.05).

show abstract

Section: Sentinel-2 Data and Processingmentioning

confidence: 99%

Monitoring Total Phosphorus Concentration in the Middle Reaches of the Yangtze River Using Sentinel-2 Satellites

Yang,

Feng,

Zhou

et al. 2024

Remote Sensing

Self Cite

View full text Add to dashboard Cite

show abstract

“…There are a total of 166 lakes that serve primarily for irrigation, fishery farming, tourism, and industrial and urban domestic water purposes (Figure 1). In recent years, due to both climate change and human activities, eutrophication has become an increasingly pressing issue for Wuhan's lakes [33][34][35].…”

Section: Study Areamentioning

confidence: 99%

Using C2X to Explore the Uncertainty of In Situ Chlorophyll-a and Improve the Accuracy of Inversion Models

Zhou

Yang

et al. 2023

Sustainability

Self Cite

View full text Add to dashboard Cite

Quality water plays a huge role in human life. Chlorophyll-a (Chl-a) in water bodies is a direct reflection of the population size of the primary productivity of various phytoplankton species in the water body and can provide critical information on the health of water ecosystems and the pollution status of water quality. Case 2 Regional CoastColour (C2RCC) is a networked atmospheric correction processor introduced by the Sentinel Application Platform for various remote sensing products. Among them, the Extreme Case-2 Waters (C2X) process has demonstrated advantages in inland complex waters, enabling the generation of band data, conc_chl product for Chl-a, and kd_z90max product for Secchi Depth (SD). Accurate in situ data are essential for the development of reliable Chl-a models, while in situ data measurement is limited by many factors. To explore and improve the uncertainties involved, we combined the C2X method with Sentinel-2 imagery and water quality data, taking lakes in Wuhan from 2018 to 2021 as a case. A Chl-a model was developed and validated using an empirical SD model and a neural network incorporating Trophic Level Index (TLI) to derive the predicted correction result, Chl-a_t. The results indicated that (1) the conc_chl product measured by C2X and in situ Chl-a exhibited consistent overall trends, with the highest correlation observed in the range of 2–10 μg/L. (2) The corrected Chl-a_t using the conc_chl product had a mean absolute error of approximately 10–15 μg/L and a root-mean-square error of approximately 8–10 μg/L, while using in situ Chl-a had a root-mean-square error (RMSE) of approximately 15 μg/L and a mean absolute error (MAE) of approximately 20 μg/L; both errors decreased by double after correction. (3) The correlation coefficient (R) between Chl-a_t and each data point in the Chl-a model results was lower than that of SD-a_t with each data point in the SD model results. Additionally, the difference in R-value between Chl-a_t and each data point (0.45–0.60) was larger than that of SD-a_t with each data point (0.35–0.5). (4) When using corrected Chl-a_t data to calculate the TLI estimation model, both RMSE and MAE decreased, which were 1μg/L lower than those derived from uncorrected data, while R increased, indicating an improvement in accuracy and reliability. These findings demonstrated the presence of in situ errors in Chl-a measurements, which must be acknowledged during research. This study holds practical significance as some of these errors can be effectively corrected through the use of C2X atmospheric correction on spectral bands.

show abstract

“…The shoreline change study is performed over three decades. Shorelines (high-water mark) are extracted from Landsat TM1989 and OLI2019 scenes with 30 m resolutions in Idrisi SELVA software by the bandratioing method (Zhou et al 2019). Shoreline change rates are computed using the End Point Rate method through the Digital Shoreline Analysis System tool of ArcGis.…”

Section: (D) Shoreline Changementioning

confidence: 99%

A preliminary assessment of coastal vulnerability for Ngazidja Island, Comoros Archipelago, Western Indian Ocean

Mahamoud

Gzam

Mohamed³

et al. 2022

Environ Earth Sci

View full text Add to dashboard Cite

In previous studies, an emphasis on the particular vulnerability of small island states to future sea-level rise and the intensity of increasing storm surges has been discussed. This preliminary assessment develops a Coastal Vulnerability Index (CVI) along the 202 km long coastline of Ngazidja Island (formerly Grande Comore, Comoros Archipelago), using eldwork, remote sensing, and geographic information system tools (GIS). The CVI considers ve structural variables: (a) geology, (b) geomorphology, (c) topography, (d) shoreline change, and (e) shoreline exposure). It also considers three physical process variables: (f) relative sea-level rise, (g) signi cant wave height, and (h) mean tide range). The land-use variable was added in this analysis to highlight the human asset exposure in the surrounding areas. Each variable was ranked based on local physical and hydrodynamic conditions and their vulnerability contribution to sea-level rise. The CVI was computed in 270 sections. According to the vulnerability index, approximately 57.5% of the coastline is under low and moderate vulnerability. High and very-high vulnerabilities refer speci cally to beaches and shores with old volcanic lava ows located mainly in the northern, northeastern, and southeastern parts of the island, approximately 42.5% of the coastline. The lowest value of CVI is 9.2 on high, rocky cliffs and the highest value is 160 on beaches. This vulnerability partition along the coastline is consistent with in situ indicators of coastal erosion and ooding. In a sealevel rise context, it is of prime importance to integrate coastal vulnerability maps with planning and sustainable management of the coastal zone.

show abstract

Retrieving the Lake Trophic Level Index with Landsat-8 Image by Atmospheric Parameter and RBF: A Case Study of Lakes in Wuhan, China

Cited by 16 publications

References 44 publications

Monitoring Total Phosphorus Concentration in the Middle Reaches of the Yangtze River Using Sentinel-2 Satellites

Monitoring Total Phosphorus Concentration in the Middle Reaches of the Yangtze River Using Sentinel-2 Satellites

Using C2X to Explore the Uncertainty of In Situ Chlorophyll-a and Improve the Accuracy of Inversion Models

A preliminary assessment of coastal vulnerability for Ngazidja Island, Comoros Archipelago, Western Indian Ocean

Contact Info

Product

Resources

About