scholarly journals Effect of Satellite Temporal Resolution on Long-Term Suspended Particulate Matter in Inland Lakes

2019 ◽  
Vol 11 (23) ◽  
pp. 2785 ◽  
Author(s):  
Zhigang Cao ◽  
Ronghua Ma ◽  
Hongtao Duan ◽  
Kun Xue ◽  
Ming Shen
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Particulate Matter ◽  
Temporal Resolution ◽  
Suspended Particulate Matter ◽  
Google Earth ◽  
Inland Lakes ◽  
Suspended Particulate ◽  
The Impact

The temporal resolution of satellite determines how well remote sensing products represent changes in the lake environments and influences the practical applications by end-users. Here, a resampling method was used to reproduce the suspended particulate matter (SPM) dataset in 43 large lakes (>50 km2) on the eastern China plain during 2003–2017 at different temporal resolutions using MODIS Aqua (MODISA) based on Google Earth Engine platform, then to address the impact of temporal resolution on the long-term SPM dataset. Differences between the MODISA-derived and reproduced SPM dataset at longer temporal resolution were higher in the areas with large water dynamics. The spatial and temporal distributions of the differences were driven by unfavorable observation environments during satellite overpasses such as high cloud cover, and rapid changes in water quality, such as water inundation, algae blooms, and macrophytes. Furthermore, the annual mean difference in SPM ranged from 5–10% when the temporal difference was less than 10 d, and the differences in summer and autumn were higher than that of other seasons and surpassed 20% when the temporal resolution was more than 16 d. To assure that difference were less than 10% for long-term satellite-derived SPM datasets, the minimal requirement of temporal resolution should be within 5 d for most of the inland lakes and 3 d for lakes with large changes in water quality. This research can be used to not only evaluate the reliability of historically remote sensing products but also provide a reference for planning field campaigns and applying of high spatial resolution satellite missions to monitor aquatic systems in the future.

scholarly journals Remote Sensing Is Changing Our View of the Coast: Insights from 40 Years of Monitoring at Narrabeen-Collaroy, Australia

2018 ◽  
Vol 10 (11) ◽  
pp. 1744 ◽  
Author(s):  
Kristen Splinter ◽  
Mitchell Harley ◽  
Ian Turner
Keyword(s):  
Remote Sensing ◽  
Data Collection ◽  
Temporal Resolution ◽  
Monitoring Program ◽  
Google Earth ◽  
Airborne Lidar ◽  
Data Collection Program ◽  
Insight Into ◽  
Collection Program

Narrabeen-Collaroy Beach, located on the Northern Beaches of Sydney along the Pacific coast of southeast Australia, is one of the longest continuously monitored beaches in the world. This paper provides an overview of the evolution and international scientific impact of this long-term beach monitoring program, from its humble beginnings over 40 years ago using the rod and tape measure Emery field survey method; to today, where the application of remote sensing data collection including drones, satellites and crowd-sourced smartphone images, are now core aspects of this continuing and much expanded monitoring effort. Commenced in 1976, surveying at this beach for the first 30 years focused on in-situ methods, whereby the growing database of monthly beach profile surveys informed the coastal science community about fundamental processes such as beach state evolution and the role of cross-shore and alongshore sediment transport in embayment morphodynamics. In the mid-2000s, continuous (hourly) video-based monitoring was the first application of routine remote sensing at the site, providing much greater spatial and temporal resolution over the traditional monthly surveys. This implementation of video as the first of a now rapidly expanding range of remote sensing tools and techniques also facilitated much wider access by the international research community to the continuing data collection program at Narrabeen-Collaroy. In the past decade the video-based data streams have formed the basis of deeper understanding into storm to multi-year response of the shoreline to changing wave conditions and also contributed to progress in the understanding of estuary entrance dynamics. More recently, ‘opportunistic’ remote sensing platforms such as surf cameras and smartphones have also been used for image-based shoreline data collection. Commencing in 2011, a significant new focus for the Narrabeen-Collaroy monitoring program shifted to include airborne lidar (and later Unmanned Aerial Vehicles (UAVs)), in an enhanced effort to quantify the morphological impacts of individual storm events, understand key drivers of erosion, and the placing of these observations within their broader regional context. A fixed continuous scanning lidar installed in 2014 again improved the spatial and temporal resolution of the remote-sensed data collection, providing new insight into swash dynamics and the often-overlooked processes of post-storm beach recovery. The use of satellite data that is now readily available to all coastal researchers via Google Earth Engine continues to expand the routine data collection program and provide key insight into multi-decadal shoreline variability. As new and expanding remote sensing technologies continue to emerge, a key lesson from the long-term monitoring at Narrabeen-Collaroy is the importance of a regular re-evaluation of what data is most needed to progress the science.

Coupling remote sensing data with in-situ optical measurements to estimate suspended particulate matter under the Evros river influence (North-East Aegean sea, Greece)

2019 ◽  
Vol 41 (6) ◽  
pp. 2062-2080
Author(s):  
Athina Tsapanou ◽  
Emmanouil Oikonomou ◽  
Panagiotis Drakopoulos ◽  
Serafeim Poulos ◽  
Georgios Sylaios
Keyword(s):  
Remote Sensing ◽  
Particulate Matter ◽  
Suspended Particulate Matter ◽  
Remote Sensing Data ◽  
Aegean Sea ◽  
Optical Measurements ◽  
North East ◽  
Suspended Particulate ◽  
Evros River

scholarly journals A Simple Empirical Band-Ratio Algorithm to Assess Suspended Particulate Matter from Remote Sensing over Coastal and Inland Waters of Vietnam: Application to the VNREDSat-1/NAOMI Sensor

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2636
Author(s):  
Dat Dinh Ngoc ◽  
Hubert Loisel ◽  
Vincent Vantrepotte ◽  
Huy Chu Xuan ◽  
Ngoc Nguyen Minh ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Particulate Matter ◽  
Suspended Particulate Matter ◽  
Band Ratio ◽  
Data Set ◽  
Spectral Bands ◽  
Processing Chain ◽  
Suspended Particulate ◽  
Data Points ◽  
Spm Concentration

VNREDSat-1 is the first Vietnamese satellite enabling the survey of environmental parameters, such as vegetation and water coverages or surface water quality at medium spatial resolution (from 2.5 to 10 m depending on the considered channel). The New AstroSat Optical Modular Instrument (NAOMI) sensor on board VNREDSat-1 has the required spectral bands to assess the suspended particulate matter (SPM) concentration. Because recent studies have shown that the remote sensing reflectance, Rrs(λ), at the blue (450–520 nm), green (530–600 nm), and red (620–690 nm) spectral bands can be assessed using NAOMI with good accuracy, the present study is dedicated to the development and validation of an algorithm (hereafter referred to as V1SPM) to assess SPM from Rrs(λ) over inland and coastal waters of Vietnam. For that purpose, an in-situ data set of hyper-spectral Rrs(λ) and SPM (from 0.47 to 240.14 g·m−3) measurements collected at 205 coastal and inland stations has been gathered. Among the different approaches, including four historical algorithms, the polynomial algorithms involving the red-to-green reflectance ratio presents the best performance on the validation data set (mean absolute percent difference (MAPD) of 18.7%). Compared to the use of a single spectral band, the band ratio reduces the scatter around the polynomial fit, as well as the impact of imperfect atmospheric corrections. Due to the lack of matchup data points with VNREDSat-1, the full VNREDSat-1 processing chain (atmospheric correction (RED-NIR) and V1SPM), aiming at estimating SPM from the top-of-atmosphere signal, was applied to the Landsat-8/OLI match-up data points with relatively low to moderate SPM concentration (3.33–15.25 g·m−3), yielding a MAPD of 15.8%. An illustration of the use of this VNREDSat-1 processing chain during a flooding event occurring in Vietnam is provided.

scholarly journals An Algorithm to Estimate Suspended Particulate Matter Concentrations and Associated Uncertainties from Remote Sensing Reflectance in Coastal Environments

2020 ◽  
Vol 12 (13) ◽  
pp. 2172 ◽  
Author(s):  
Juliana Tavora ◽  
Emmanuel Boss ◽  
David Doxaran ◽  
Paul Hill
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Particulate Matter ◽  
Suspended Particulate Matter ◽  
Ocean Color ◽  
Major Constituent ◽  
Coastal Environments ◽  
Suspended Particulate ◽  
Spm Concentration

Suspended Particulate Matter (SPM) is a major constituent in coastal waters, involved in processes such as light attenuation, pollutant propagation, and waterways blockage. The spatial distribution of SPM is an indicator of deposition and erosion patterns in estuaries and coastal zones and a necessary input to estimate the material fluxes from the land through rivers to the sea. In-situ methods to estimate SPM provide limited spatial data in comparison to the coverage that can be obtained remotely. Ocean color remote sensing complements field measurements by providing estimates of the spatial distributions of surface SPM concentration in natural waters, with high spatial and temporal resolution. Existing methods to obtain SPM from remote sensing vary between purely empirical ones to those that are based on radiative transfer theory together with empirical inputs regarding the optical properties of SPM. Most algorithms use a single satellite band that is switched to other bands for different ranges of turbidity. The necessity to switch bands is due to the saturation of reflectance as SPM concentration increases. Here we propose a multi-band approach for SPM retrievals that also provides an estimate of uncertainty, where the latter is based on both uncertainties in reflectance and in the assumed optical properties of SPM. The approach proposed is general and can be applied to any ocean color sensor or in-situ radiometer system with red and near-infra-red bands. We apply it to six globally distributed in-situ datasets of spectral water reflectance and SPM measurements over a wide range of SPM concentrations collected in estuaries and coastal environments (the focus regions of our study). Results show good performance for SPM retrieval at all ranges of concentration. As with all algorithms, better performance may be achieved by constraining empirical assumptions to specific environments. To demonstrate the flexibility of the algorithm we apply it to a remote sensing scene from an environment with highly variable sediment concentrations.

scholarly journals A influência antrópica na qualidade da água do rio Tapajós, na cidade de Santarém-PA

2021 ◽  
Vol 14 (6) ◽  
pp. 3695
Author(s):  
Christiane Do Nascimento Monte ◽  
Ana Paula De Castro Rodrigues ◽  
Sara Macedo ◽  
Carolina Ramos Régis ◽  
Edinelson Correa Saldanha ◽  
...  
Keyword(s):  
Water Quality ◽  
Particulate Matter ◽  
Suspended Particulate Matter ◽  
Inorganic Phosphorus ◽  
Northern Region ◽  
Social Functions ◽  
Suspended Particulate ◽  
Anthropic Influence ◽  
The City

O Rio Tapajós é uma das maiores bacias hidrográficas da região Norte do país, e o crescimento populacional de algumas cidades amazônicas coloca em risco a qualidade das suas águas. A cidade de Santarém, no Oeste do Pará, é uma das maiores cidades paraenses e não tem uma rede de esgoto eficiente, logo boa parte do esgoto doméstico é lançado in natura em igarapés e no rio Tapajós, o que afeta diretamente a balneabilidade do rio, que é um dos destinos turísticos em ascensão no país, devido às praias de água doce, a qualidade do pescado, que é parte da dieta alimentar da região e pode ser um vetor de doenças, as quais podem aumentar os gastos com a saúde pública. Com o objetivo de avaliar a influência antrópica no rio Tapajós foi realizada uma amostragem em seis pontos do rio na região conhecida como a orla da cidade. Foram analisados parâmetros físico-químicos, biológicos e nutrientes), Apesar de boa parte dos parâmetros estarem em conformidade com a CONAMA 357/05, os parâmetros biológicos foram acima do permitido para a classe II, indicando influência antrópica. Os dados apontaram que a presença de material particulado em suspensão (MPS), coliformes totais e fósforo inorgânico dissolvido (PID), sugerem aumento da degradação da qualidade da água.  O estudo da queda na qualidade de água nos rios amazônicos é importante, pois a relação socioeconômica entre a população e os recursos hídricos é muito importante para a manutenção das funções ambientais, econômicas e sociais na região.   The anthropic influence on the water quality of the Tapajós River, in the city of Santarém-PA A B S T R A C TThe Tapajós River is one of the largest hydrographic basins of the Northern region of the country, and the population growth of some Amazonian cities puts the quality of its waters at risk. The city of Santarém, in western Pará, is one of the largest cities in Pará and does not have an efficient sewage system, so much of the domestic sewage is released in natura into streams and the Tapajós River, which directly affects the balneability of the river, which is one of the tourist destinations on the rise in the country, due to its freshwater beaches, the quality of the fish, which is part of the diet of the region and can be a vector of diseases, which can increase spending on public health. To evaluate the anthropic influence on the Tapajós River, sampling was carried out at six points on the river in the region known as the city edge. Although most of the parameters complied with CONAMA 357/05, the biological parameters were above the permitted for class II, indicating anthropic influence. The data pointed out that the presence of suspended particulate matter (SPM), total coliforms, and dissolved inorganic phosphorus (DIP), suggest increased degradation of water quality.  The study of the decline in water quality in Amazonian rivers is important because the socioeconomic relationship between the population and water resources is very important for the maintenance of environmental, economic, and social functions in the region. Keywords: Tapajós River, sewage, inorganic phosphorus, suspended particulate matter

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