Article
Environmental Sciences
Bridget N. Seegers, P. Jeremy Werdell, Ryan A. Vandermeulen, Wilson Salls, Richard P. Stumpf, Blake A. Schaeffer, Tommy J. Owens, Sean W. Bailey, Joel P. Scott, Keith A. Loftin
Summary: This study highlights the importance of lakes and other surface fresh waterbodies for humans, aquatic life, and ecosystem health, and examines the use of satellite remote sensing data for monitoring inland water quality. The researchers developed a new chlorophyll algorithm using satellite remote sensing data, and evaluated its ability to assess lake trophic state across the CONUS.
REMOTE SENSING OF ENVIRONMENT
(2021)
Article
Environmental Sciences
Lien Rodriguez-Lopez, Iongel Duran-Llacer, Lisdelys Gonzalez-Rodriguez, Rolando Cardenas, Roberto Urrutia
Summary: Remote sensing was used to develop empirical models for estimating turbidity in Araucanian Lakes, revealing temporal-spatial patterns of turbidity variation. The study found that meteorological conditions, particularly precipitation and wind speed, may affect turbidity changes. These models will be valuable for analyzing transparency trends in the lakes in the future.
Article
Environmental Sciences
Michael A. Dallosch, Irena F. Creed
Summary: This study utilized remote sensing reflectance data and water chemistry to identify seven unique optical water types in inland lakes. The performance of chlorophyll-a retrieval algorithms for each optical water type was compared, showing improved predictive ability compared to algorithms for all lakes combined.
Article
Geochemistry & Geophysics
Zhigang Cao, Ronghua Ma, Jianqiang Liu, Jing Ding
Summary: The study evaluated the performance of the coastal zone imager (CZI) in monitoring inland lake environments, comparing it with other measurement methods. CZI showed comparable signal-to-noise ratios with other instruments in visible and near-infrared bands, and demonstrated higher accuracy in remote sensing reflectance retrieval. Additionally, CZI exhibited good performance in observing cyanobacterial bloom, suspended particulate matter, and chlorophyll-a, showing potential for further research in small-medium lakes.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2021)
Article
Geochemistry & Geophysics
Zhigang Cao, Ronghua Ma, Miao Liu, Hongtao Duan, Qing Xiao, Kun Xue, Ming Shen
Summary: Moderate-high-resolution satellite missions provide an opportunity to capture subtle spatial variability in lakes. A harmonized Chl-a dataset for lakes in the Yunnan-Guizhou Plateau in China was generated using the Landsat 8/9 and Sentinel-2A/B virtual constellation. The study examined the performance of four atmospheric correction processors and found that the dark spectral fitting algorithm produced better results.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Ecology
Lien Rodriguez-Lopez, Lisdelys Gonzalez-Rodriguez, Iongel Duran-Llacer, Rolando Cardenas, Roberto Urrutia
Summary: This study aimed to analyze the spatial and temporal variation of Chl-a values in six Araucanian lakes in Central-South Chile. By combining in-situ measurements and satellite images, models were created to estimate Chl-a values and validated using statistical indicators. The study observed higher Chl-a values in lakes during the Summer months compared to Spring, with the presence of two invasive species potentially impacting the lake ecosystems.
ECOLOGICAL INFORMATICS
(2021)
Article
Environmental Sciences
Shijiao Lu, Yingchun Bian, Fangfang Chen, Jie Lin, Heng Lyu, Yunmei Li, Huaiqing Liu, Yang Zhao, Yiling Zheng, Linze Lyu
Summary: A water classification algorithm based on satellite data was developed to accurately estimate water clarity, and it showed good performance in different types of water bodies. The algorithm was successfully applied to monitor and manage water quality in 107 lakes and reservoirs.
ENVIRONMENTAL RESEARCH
(2023)
Article
Environmental Sciences
Yunxia Du, Kaishan Song, Ge Liu
Summary: This study uses satellite remote sensing data to classify water bodies into three optical types based on unsupervised cluster analysis. The results show that each optical water type is associated with different bio-optical properties.
Article
Environmental Sciences
Davide De Santis, Fabio Del Frate, Giovanni Schiavon
Summary: This study characterizes the water surface temperature of two small-medium Italian lakes using satellite data. The results show an overall increase in water surface temperatures, which is more evident in the smallest and shallowest lake.
Article
Environmental Sciences
Dong Wang, Bo-Hui Tang, Zhitao Fu, Liang Huang, Menghua Li, Guokun Chen, Xuejun Pan
Summary: The quantitative retrieval of chlorophyll-a concentration is important for monitoring the nutritional status of water bodies. This study used Sentinel-2 MSI and in situ measurements to investigate the chlorophyll-a concentrations and surface temperatures of plateau lakes in the Yunnan-Kweichow Plateau of China. The results showed consistency between retrievals and actual measurements, providing support for remote sensing monitoring and effective management of plateau lakes.
Article
Water Resources
Chi-Ming Lee, Chung -Yen Kuo, Chi-Hua Yang, Huan-Chin Kao, Kuo-Hsin Tseng, Wen-Hau Lan
Summary: This study utilized Landsat imagery and satellite altimetry to monitor the long-term variations of water level and water volume in Tsengwen Reservoir, Taiwan. The results demonstrated that the integration of multi-source remote sensing technologies can effectively provide accurate hydrological parameters for water resources management.
JOURNAL OF HYDROLOGY-REGIONAL STUDIES
(2022)
Article
Environmental Sciences
Yanqun Pan, Simon Belanger, Yannick Huot
Summary: Atmospheric correction of satellite optical imagery over inland waters is a challenging task in aquatic remote sensing. The tested algorithms did not meet the retrieval accuracy target due to uncorrected adjacency effects.
Article
Environmental Sciences
Li Lu, Zhaoning Gong, Yanan Liang, Shuang Liang
Summary: This study utilized the ZY1-02D hyperspectral satellite subdivision and in situ measured chlorophyll-a concentration to establish a quantitative hyperspectral model for the chlorophyll-a concentration of inland lakes. The study evaluated and analyzed the chlorophyll-a concentration of Baiyangdian Lake and created a spatial distribution map using ZY1-02D hyperspectral data.
Article
Environmental Sciences
Jiasheng Xu, Guoqing Zhou, Sikai Su, Qiaobo Cao, Zhou Tian
Summary: Models for bathymetry retrieval from multispectral images usually neglect the errors caused by tidal fluctuation. In this paper, a rigorous model that considers the variation in tide height time series is proposed. The model was applied and validated on Weizhou Island using Landsat 8 satellite imagery, and it significantly improved the accuracy of bathymetry retrieval compared to traditional models.
Article
Environmental Sciences
Stephan Buettig, Marie Lins, Sebastian Goihl
Summary: This paper discusses the development of an open-source demo software WaterMaskAnalyzer (WMA) that uses freely available satellite imagery from the EU Copernicus program to accurately determine water body extents. The tool allows simple and on-demand monitoring of inland water dynamics and can address various hydrological issues. The initial results show high accuracy for some water bodies but lower accuracy for others, suggesting the need for improvements in classification methods and the incorporation of diverse ground-truth data.
Article
Geography, Physical
Godfrey Mutowo, Onisimo Mutanga, Mhosisi Masocha
Summary: This study used high resolution broadband satellite technology to determine the optimal spatial resolution for estimating foliar nitrogen in dry miombo woodlands. The results found that the optimum size for estimating nitrogen is 50m.
JOURNAL OF SPATIAL SCIENCE
(2023)
Article
Environmental Sciences
Obianuju Patience Ilo, S'phumelele Lucky Nkomo, Ntandoyenkosi Malusi Mkhize, Onisimo Mutanga, Mulala Danny Simatele
Summary: The water hyacinth is a persistent threat to sustainability and requires cost-effective mitigation measures. The study optimized the process parameters, specifically temperature and particle size, to improve the liquid fraction yield from the pyrolysis of water hyacinths. Increased temperature and particle size led to a higher liquid fraction and lower char content. The study emphasizes the potential socio-economic and environmental benefits of utilizing water hyacinths and hopes to inform policy discussions.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Environmental Sciences
Mangana B. B. Rampheri, Timothy Dube, Farai Dondofema, Tatenda Dalu
Summary: This study used remote sensing, analytical hierarchy process (AHP) and in situ data to identify and delineate groundwater-dependent ecosystems (GDEs) in the Khakea-Bray transboundary aquifer region. The results showed that only 1.34% of the area is characterized by GDEs, mostly located on grasslands and shrublands.
GEOCARTO INTERNATIONAL
(2023)
Article
Environmental Studies
Lwando Royimani, Onisimo Mutanga, John Odindi, Rob Slotow
Summary: Climate and topography influence the autumn senescence of grassland ecosystems. However, there is limited understanding of the remote-sensing-derived environmental variables that affect autumn grassland senescence, especially in tropical and subtropical regions. This study aimed to examine the spatial autocorrelations between remotely sensed autumn grass senescence and climatic and topographic variables in subtropical grasslands, and to determine the key environmental drivers of autumn grassland senescence.
Article
Environmental Studies
Dadirai Matarira, Onisimo Mutanga, Maheshvari Naidu, Marco Vizzari
Summary: This study demonstrates the use of Geographic Object-Based Image Analysis (GEOBIA) combined with Google Earth Engine (GEE) and high-spatial-resolution PlanetScope imagery to map the spatial morphology of informal settlements in a complex built-up environment. The findings highlight the effectiveness of this approach in capturing the spatial characteristics of informal settlements with high accuracy.
Article
Environmental Sciences
Tsikai Solomon Chinembiri, Onisimo Mutanga, Timothy Dube
Summary: This study compares the performance of two geostatistical approaches for predicting C stock. The results show that the Bayesian approach is more accurate when using Sentinel-2 data compared to the frequentist approach.
Article
Biodiversity Conservation
Nthabe Munyai, Abel Ramoelo, Samuel Adelabu, Hugo Bezuidenhout
Summary: The study aims to determine the influence of fire on grass species richness, diversity, and composition in Mountain Zebra National Park. The results showed no significant difference in species richness and diversity between burned and unburned sites, but there were differences in species composition.
Article
Chemistry, Multidisciplinary
Anita Masenyama, Onisimo Mutanga, Timothy Dube, Mbulisi Sibanda, Omosalewa Odebiri, Tafadzwanashe Mabhaudhi
Summary: Indicators of grass water content (GWC) have a significant impact on eco-hydrological processes. In this study, Sentinel-2 MSI bands, spectral derivatives combined with topographic and climatic variables, were used to estimate GWC indicators within communal grasslands. The results showed that the use of combined spectral and topo-climatic variables, coupled with random forest (RF) in the Google Earth Engine (GEE), improved the prediction accuracies of GWC variables across wet and dry seasons.
APPLIED SCIENCES-BASEL
(2023)
Article
Multidisciplinary Sciences
Ezra Pedzisai, Onisimo Mutanga, John Odindi, Tsitsi Bangira
Summary: Flood disasters have severe impacts on infrastructure, ecosystems, and social activities, making flood extent mapping crucial for mitigation efforts. This study proposes a three-step process, called the ensemble of scenarios pyramid technique, using Sentinel-1 radar data to improve the reliability and accuracy of flood extent mapping. The results demonstrate that this technique significantly enhances the performance metrics of flood extent mapping, with an overall accuracy of 93.204% and other metrics such as Cohen's Kappa and recall reaching high values. The study also concludes that VV channels outperform VH channels in flood extent mapping.
Article
Geography
Matilda Azong Cho, O. Mutanga, T. Mabhaudhi
Summary: Rangelands in arid and semi-arid regions play a crucial role in supporting the livelihoods of pastoral communities. However, these rangelands are exposed to threats from natural, social, economic, and political processes, which affect their ability to provide socioeconomic and environmental support. Existing literature mainly focuses on assessing threats to the biophysical environment, while the social dimension of rangeland threats is often overlooked. This research used participatory rural appraisal and PGIS techniques to assess rangeland threats and management actions from a local perspective, revealing that local communities prioritize threats to their social and economic needs. The findings emphasize the importance of interdisciplinary and inclusive participation in rangeland governance.
SOUTH AFRICAN GEOGRAPHICAL JOURNAL
(2023)
Article
Geography
Chantel Chiloane, Timothy Dube, Cletah Shoko
Summary: This study assesses the distribution of groundwater dependent vegetation (GDV) within the Heuningnes Catchment using multispectral remotely sensed data, vegetation indices, and in-situ data. The findings show that spectral indices significantly influence the GDV classification performance, with S2-derived SAVI achieving the highest overall accuracy of 97%. The study demonstrates the capabilities of a combined remote sensing and GIS framework for improving our knowledge of GDV.
SOUTH AFRICAN GEOGRAPHICAL JOURNAL
(2023)
Article
Environmental Sciences
Adeola. M. Arogoundade, Onisimo Mutanga, John Odindi, Omosalewa Odebiri
Summary: Rangelands play a crucial role in providing fodder and ecosystem services, and understanding the C:N ratio can help in managing their health and productivity. Remote sensing techniques, specifically the use of the Sentinel 2 multispectral sensor, offer a cost-effective and efficient way to monitor foliar nutrient ratios in rangelands. The study demonstrates the potential of mapping the C:N ratio using these techniques and provides valuable information for rangeland management.
REMOTE SENSING APPLICATIONS-SOCIETY AND ENVIRONMENT
(2023)
Review
Engineering, Civil
Timothy Dube, Dylan Seaton, Cletah Shoko, Cheikh Mbow
Summary: This paper provides an overview of the progress made in remote sensing of water resources in Africa. The study highlights the remarkable advancements in various applications such as precipitation estimation, land surface temperature analysis, and water quality evaluation. It also identifies the challenges faced and the knowledge gaps that need to be addressed for further advancements in this field.
JOURNAL OF HYDROLOGY
(2023)
Review
Environmental Sciences
Makgabo Johanna Mashala, Timothy Dube, Bester Tawona Mudereri, Kingsley Kwabena Ayisi, Marubini Reuben Ramudzuli
Summary: This study provides an overview of the progress made in using remote sensing to assess the impacts of land use and land cover changes on water resources. The study highlights advancements in technology and methodologies, such as high-resolution satellite imagery and advanced classification techniques, which have improved the accuracy of land cover mapping and change detection. The study also emphasizes the potential for detailed information on the relationship between land use and water resources through advancements in data science analytics, drones, web-based platforms, and balloons.
Article
Environmental Sciences
Trisha Deevia Bhaga, Timothy Dube, Munyaradzi Davis Shekede, Cletah Shoko
Summary: This study assesses the use of Landsat-8 OLI and Sentinel-2 MSI satellite data to characterize and monitor the impacts of drought on water resources in the Western Cape, South Africa. Different multispectral indices were computed to determine the most suitable method for surface water detection and drought monitoring. The findings provide valuable insights into surface water variability and the impacts of drought on water resources.
REMOTE SENSING APPLICATIONS-SOCIETY AND ENVIRONMENT
(2023)
