Research on retrieval of chlorophyll-a concentration in Danjiangkou-Fancheng reach of Han River based on Sentinel-2 satellite data

2021 ◽  
Author(s):  
Furong Zhang ◽  
He Zhu ◽  
Shifeng Huang ◽  
Jianwei Ma ◽  
Yayong Sun ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Satellite Data ◽  
Chlorophyll A Concentration ◽  
Han River ◽  
Sentinel 2

scholarly journals VARIABILITY OF CHLOROPHYLL-a CONCENTRATION OF THE NORTHERN SUMBAWA WATERS BASED ON Sea WiFS SATELLITE DATA

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Bisman Nababan ◽  
Diki Zulkarnaen ◽  
Jonson Lumban Gaol
Keyword(s):  
Chlorophyll A ◽  
Satellite Data ◽  
Coastal Waters ◽  
Low Temperatures ◽  
Water Mass ◽  
The West ◽  
Chlorophyll A Concentration ◽  
Transition Season ◽  
Goddard Space Flight Center ◽  
Second Peak

<p>Variability of chlorophyll-a concentrations of the northern Sumbawa waters was investigated based on SeaWiFS satellite data for the period of January 1998-December 2007. Chlorophyll-aconcentration was estimated employing OC4v4 algorithm. Chlorophyll-a concentrations of,SeaWiFS satellite data were obtained from the Goddard Space Flight Center, NASA archieve data. In general, fluctuations of chlorophyll-a concentration of the northern Sumbawa waters had three patterns i.e., the maximum with a range of 0,21-0,74 mg/m3 occurred during the West Season (November-February), the minimum with a range of 0.12-0.15 mg/m3 occurred during Transition Season I (March-April), and relatively high (second peak) with a range of 0.21-0.36 mg/m3 occurred during the mid-East Season until the beginning of Transition Season II (July-September).High chlorophyll-a concentration occurred during the West Season was closely related to the high rainfall, the possibility of vertical water mass mixing,and upwelling process in the northern coastal waters of Sumbawa. Meanwhile, the relatively high (second peak) of chlorophyll-aconcentration occurred in July-September was caused by the movement of water masses from the South of Makassar Strait containing relatively high chlorophyll-a concentrations and relatively low temperatures since upwelling processes occurred at this location in the same period.</p> <p>Keywords:Chlorophyll-a,northern Sumbawa waters, SeaWiFS, OC4v4, upwelling</p> <p> </p>

scholarly journals Chlorophyll-a concentration retrieval in eutrophic lakes in Lithuania from Sentinel-2 data

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Dalia Grendaitė ◽  
Edvinas Stonevičius ◽  
Jūratė Karosienė ◽  
Ksenija Savadova ◽  
Jūratė Kasperovičienė
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Remote Sensing Data ◽  
Empirical Equations ◽  
Active Constituent ◽  
Eutrophic Lakes ◽  
Band Ratio ◽  
Local Conditions ◽  
Chlorophyll A Concentration ◽  
Sentinel 2

Inland waters are an important habitat for flora and fauna and are also used for aesthetic, recreational, and industrial needs; therefore, monitoring the current state of freshwaters and applying measures to improve water quality are of high importance. To have an efficient monitoring system that could cover large areas, the use of remote sensing data is crucial. In this study the suitability of the Sentinel-2 Multispectral Imager data is tested for observing cyanobacteria bloom events in the eutrophic lakes and retrieving the chlorophyll-a concentration – an indicator of phytoplankton biomass. The analysis is carried out using data from four lakes in Lithuania – two eutrophic blooming lakes and two oligo-mesotrophic non-blooming lakes. The results showed that reflectances are higher in the eutrophic lakes than in the oligo-mesotrophic lakes due to the presence of an optically active constituent, namely, chlorophyll-a pigment. We tested empirical equations for chlorophyll-a concentration retrieval in eutrophic lakes derived in other studies to check whether they could be used without adaptation to local conditions. Most of the equations performed well (R2 = 0.5–0.8); however, they had high RMSEs = 17–53 μg L–1. The equation used with the bottom of atmosphere data CHL8_L2A (R2 = 0.76) had the lowest RMSE = 9 μg L–1. In addition, we derived empirical equations for eutrophic lakes in Lithuania. The equations that were based on the Sentinel-2 band ratio B5/B4 and the three band (B4, B5, and B8A) expression performed the best (R2 = 0.77–0.79) and had lower RMSE = 7 μg L–1 than empirical equations from other studies. A larger in situ dataset could improve the algorithm performance in retrieving the chlorophyll-a concentration. The first attempts to map water quality parameters in eutrophic lakes in Lithuania using the data received from the Sentinel-2 MSI sensor show good results, as the changes in reflectance, caused by the changes in chlorophyll-a concentration, can be seen from satellite images.

scholarly journals Determinação da Concentração de Clorofila-a por Sensoriamento Remoto no Reservatório de Chapéu d’Úvas (Mg), Brasil

2021 ◽  
Vol 14 (6) ◽  
pp. 3561
Author(s):  
Larissa Ferreira Serbeto ◽  
George Mendes ◽  
Celso Bandeira de Melo Ribeiro ◽  
Renata De Oliveira Pereira
Keyword(s):  
Remote Sensing ◽  
Water Supply ◽  
Chlorophyll A ◽  
Trophic State ◽  
The Body ◽  
Component Concentration ◽  
Public Water Supply ◽  
Trophic State Index ◽  
Chlorophyll A Concentration ◽  
Sentinel 2

Na atualidade, um grande impacto nos reservatórios de água doce é a eutrofização, que afeta diretamente o tratamento e uso da água para abastecimento público, navegação, fauna e flora aquática e impacto visual. A clorofila-a é um dos indicadores de estado trófico da água e pode ser determinada utilizando sensoriamento remoto. Desta forma, este estudo objetivou determinar a concentração de clorofila-a na barragem de Chapéu d’Uvas em Juiz de Fora (Brasil), um dos principais mananciais de abastecimento público da cidade. Através de um modelo utilizando imagens do satélite Sentinel-2 foi avaliado o comportamento espaço-temporal da concentração do componente, foi correlacionado com dados de pluviosidade, temperatura, evaporação e uso e ocupação do solo em torno da barragem. Também foi aplicado um modelo para determinar o índice de estado trófico, que apresenta o grau de trofia que o corpo hídrico se encontra, classificando Chapéu d’Uvas como estado mesotrófico. Os resultados se mostraram satisfatórios para a espacialização e análise temporal da concentração de clorofila-a, a correlação com os dados de evaporação nos permitiu observar uma compatibilidade direta com a concentração do componente e verificou-se valores de clorofila-a acima da média do reservatório nas regiões de entradas de água pelos riachos e próximos as margens com menos cobertura de vegetação.Determination of Chlorophyll-a Concentration from Remote Sensing in Chapéu d’Úvas Reservoir (State of Minas Gerais, Brazil) A B S T R A C TCurrently, one of the great impacts on the freshwater reservoirs is eutrophication, which directly affects the treatment and use of water for public water supply, navigation, aquatic fauna and flora and visual impact. Chlorophyll-a is one of the water trophic state indicators and it can be determined using remote sensing. Thus, this study aimed to determine chlorophyll-a concentration in Chapéu d’Uvas dam, in Juiz de Fora (Brazil), one of the main water sources of public water supply for the city. From a model that uses Sentinel-2 satellite images, the spatial-temporal behavior of that component concentration was evaluated and correlated with data regarding rainfall, temperature, evaporation, and soil use and occupation around the dam. A model was also applied to determine trophic state index, which presents the body of water trophic state, classifying Chapéu d’Uvas as mesotrophic state. The results were satisfactory regarding spatialization and temporal analysis of chlorophyll-a concentration. The correlation with evaporation data permitted us to observe a direct correspondence with the component concentration. Chlorophyll-a values higher than the reservoir average were found in creek inlets and near the shore with lower vegetal cover.Keywords: eutrophication, Sentinel-2, quality of water, inland waters, trophic state

scholarly journals Retrieval and mapping of chlorophyll-a concentration from Sentinel-2 images in an urban river in the semiarid region of Brazil

2020 ◽  
Vol 15 (2) ◽  
pp. 1
Author(s):  
Alessandro Rhadamek Alves Pereira ◽  
João Batista Lopes ◽  
Giovana Mira de Espindola ◽  
Carlos Ernando da Silva
Keyword(s):  
Chlorophyll A ◽  
River Mouth ◽  
Water Quality Monitoring ◽  
Semiarid Region ◽  
Surface Reflectance ◽  
Chlorophyll A Concentration ◽  
In Situ Data ◽  
Sentinel 2A ◽  
Sentinel 2

Recently, the Poti river mouth region has experienced environmental impacts that resulted in a change of landscape in its dry season, highlighting the eutrophication and proliferation of phytoplankton, algae, cyanobacteria and aquatic plants. Considering the aspects related to water-quality monitoring in the semiarid region of Brazil from remote sensing, this study aimed to evaluate the performance of Sentinel-2A satellite data in the retrieval of chlorophyll-a concentration in Poti River in Teresina, Piaui, Brazil. The chlorophyll-a concentration retrieval and mapping methodology involved the study of the water surface reflectance in Sentinel-2A images and their correlation with the chlorophyll-a data collected in situ during the years 2016 and 2017. The results generated by the Chl-1, Ha et al. (2017), Chl-2, Page et al. (2018), and Chl-3, Kuhn et al. (2019) equations show the need for calibrating the algorithms used for the Poti River water components. However, the empirical algorithm Chl-2 shows a correlation has been established to identify the spatiotemporal variation of chlorophyll-a concentration along the Poti River broadly and not punctually. The spatial distribution of this pigment in maps derived from Sentinel-2A is consistent with the pattern of occurrence determined by the in situ data. Therefore, the MSI sensor proved to be a tool suitable for the retrieval and monitoring of chlorophyll-a concentration along the Poti River.

scholarly journals VARIABILITY OF CHLOROPHYLL-a CONCENTRATION OF THE NORTHERN SUMBAWA WATERS BASED ON Sea WiFS SATELLITE DATA

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Bisman Nababan ◽  
Diki Zulkarnaen ◽  
Jonson Lumban Gaol
Keyword(s):  
Chlorophyll A ◽  
Satellite Data ◽  
Coastal Waters ◽  
Low Temperatures ◽  
Water Mass ◽  
The West ◽  
Chlorophyll A Concentration ◽  
Transition Season ◽  
Goddard Space Flight Center ◽  
Second Peak

Variability of chlorophyll-a concentrations of the northern Sumbawa waters was investigated based on SeaWiFS satellite data for the period of January 1998-December 2007. Chlorophyll-aconcentration was estimated employing OC4v4 algorithm. Chlorophyll-a concentrations of,SeaWiFS satellite data were obtained from the Goddard Space Flight Center, NASA archieve data. In general, fluctuations of chlorophyll-a concentration of the northern Sumbawa waters had three patterns i.e., the maximum with a range of 0,21-0,74 mg/m3 occurred during the West Season (November-February), the minimum with a range of 0.12-0.15 mg/m3 occurred during Transition Season I (March-April), and relatively high (second peak) with a range of 0.21-0.36 mg/m3 occurred during the mid-East Season until the beginning of Transition Season II (July-September).High chlorophyll-a concentration occurred during the West Season was closely related to the high rainfall, the possibility of vertical water mass mixing,and upwelling process in the northern coastal waters of Sumbawa. Meanwhile, the relatively high (second peak) of chlorophyll-aconcentration occurred in July-September was caused by the movement of water masses from the South of Makassar Strait containing relatively high chlorophyll-a concentrations and relatively low temperatures since upwelling processes occurred at this location in the same period. Keywords:Chlorophyll-a,northern Sumbawa waters, SeaWiFS, OC4v4, upwelling  

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