scholarly journals Retrieval of Chlorophyll a from Sentinel-2 MSI Data for the European Union Water Framework Directive Reporting Purposes

2018 ◽  
Vol 11 (1) ◽  
pp. 64 ◽  
Author(s):  
Ave Ansper ◽  
Krista Alikas
Keyword(s):  
European Union ◽  
Water Framework Directive ◽  
Chlorophyll A ◽  
Temporal Dynamics ◽  
Atmospheric Correction ◽  
European Space Agency ◽  
Ecological Status ◽  
Water Bodies ◽  
The European Union ◽  
Sentinel 2

The European Parliament and The Council of the European Union have established the Water Framework Directive (2000/60/EC) for all European Union member states to achieve, at least, “good” ecological status of all water bodies larger than 50 hectares in Europe. The MultiSpectral Instrument onboard European Space Agency satellite Sentinel-2 has suitable 10, 20, 60 m spatial resolution to monitor most of the Estonian lakes as required by the Water Framework Directive. The study aims to analyze the suitability of Sentinel-2 MultiSpectral Instrument data to monitor water quality in inland waters. This consists of testing various atmospheric correction processors to remove the influence of atmosphere and comparing and developing chlorophyll a algorithms to estimate the ecological status of water in Estonian lakes. This study shows that the Sentinel-2 MultiSpectral Instrument is suitable for estimating chlorophyll a in water bodies and tracking the spatial and temporal dynamics in the lakes. However, atmospheric corrections are sensitive to surrounding land and often fail in narrow and small lakes. Due to that, deriving satellite-based chlorophyll a is not possible in every case, but initial results show the Sentinel-2 MultiSpectral Instrument could still provide complementary information to in situ data to support Water Framework Directive monitoring requirements.

In-Situ Validation of Water Quality Algorithms and Monitoring of Irish Lakes using Sentinel 2 Imagery

2020 ◽  
Author(s):  
Sita Karki ◽  
Kevin French ◽  
Valerie McCarthy ◽  
Jennifer Hanafin ◽  
Eleanor Jennings ◽  
...  
Keyword(s):  
Water Quality ◽  
Time Window ◽  
Atmospheric Correction ◽  
European Space Agency ◽  
Weather Condition ◽  
Water Bodies ◽  
Observation Data ◽  
Field Validation ◽  
Field Samples ◽  
Sentinel 2

<p>Through Remote Sensing of Irish Surface Water (INFER) project, we are validating the algorithms to measure the  water quality using Sentinel 2 imagery, which comprises of two European Space Agency (ESA) terrestrial satellites with combined temporal resolution of 5 days. The project is focused on selection of optimal algorithms that will be applicable in Irish context in relation to the high cloud cover and relatively small sizes of the water bodies. The current procedure entails collection of reflectance data from the lakes during the Sentinel overpass as it helps to identify the correct atmospheric correction algorithm. Field radiometry tasks were carried out using TRIOS RAMSES radiometers. Standard field procedures were employed for acquiring glint free reflectance from the water bodies.</p><p>Historical data collected from the 11 lakes, which had field bathymetry survey data, were analysed in order to determine the influence of environmental conditions on the quality of samples. Based on the analysis, recommendations to collect field samples from areas deeper than 10 m and 30 m away from the shoreline were provided in order to avoid the reflectance from the bottom and the surrounding topography. A site selection process was undertaken during the spring of 2019 to shortlist appropriate sites for field validation of satellite-derived products. A total of fifteen lakes were identified for field validation based on several criteria so as to ensure lakes with varying size, depth, trophic status and Water Framework Directive (WFD) status . In addition, a timetable for proposed sampling was established by drawing up a timetable of satellite passes starting from summer of 2019. C2RCC and Acolite processors are being used to compute the chlorophyll and turbidity from identified lakes. Considering the fast changing weather condition of Ireland, it was difficult to obtain the exact overlap between the sentinel overpass and the field sampling. In order to address this issue, the field samples collected within 10 days from the sensor overpass were considered for the field validation. Study of the satellite derived water chemistry data showed that the data collected outside of that time window may not represent the natural fluctuation that occurs in the water bodies.</p><p>The end product of this project is the web platform with the access to Sentinel 2 MSI data products where users can visualize the water quality products for Ireland. This platform will promote the use of earth observation data for inland water quality monitoring and would enable sustainable utilization of the water resources.</p>

scholarly journals Copernicus Sentinel-2 Calibration and Products Validation Status

2016 ◽  
Author(s):  
Ferran Gascon ◽  
Olivier Thépaut ◽  
Mathieu Jung ◽  
Benjamin Francesconi ◽  
Jérôme Louis ◽  
...  
Keyword(s):  
European Union ◽  
High Spatial Resolution ◽  
European Space Agency ◽  
Current Status ◽  
The European Union ◽  
Space Agency ◽  
Quality Aspects ◽  
Optical Imagery ◽  
Sentinel 2

As part of the Copernicus programme of the European Union (EU), the European Space Agency (ESA) has developed and is currently operating the Sentinel-2 mission that is acquiring high spatial resolution optical imagery. This paper provides a description of the calibration activities and the current status of the mission products validation activities. Measured performances, from the validation activities, cover both Top-Of-Atmosphere (TOA) and Bottom-Of-Atmosphere (BOA) products. Results presented in this paper show the good quality of the mission products both in terms of radiometry and geometry and provide an overview on next mission steps related to data quality aspects.

scholarly journals The role of alkalinity in setting water quality metrics: phosphorus standards in United Kingdom rivers

2018 ◽  
Vol 20 (10) ◽  
pp. 1361-1372
Author(s):  
Alan D. Tappin ◽  
Alba Navarro-Rodriguez ◽  
Sean D. W. Comber ◽  
Paul J. Worsfold
Keyword(s):  
Water Quality ◽  
European Union ◽  
United Kingdom ◽  
Water Framework Directive ◽  
Reference Conditions ◽  
Ecological Status ◽  
Quality Metrics ◽  
The European Union ◽  
Reactive Phosphorus

UK implementation of the European Union Water Framework Directive (for the 2015–2021 cycle) Ecological Status (ES) classification for river phosphorus is based on the calculation of reference conditions for reactive phosphorus (RP) using river alkalinity measurements.

Setting the threshold: An analysis of different approaches for the definition of exemptions to water quality objectives in the European Union

2020 ◽  
Author(s):  
Antonio Bolinches ◽  
Lucia De Stefano ◽  
Javier Paredes-Arquiola ◽  
Carlotta Valerio ◽  
Alberto Garrido
Keyword(s):  
Water Quality ◽  
European Union ◽  
Wastewater Treatment ◽  
Water Framework Directive ◽  
River Basin ◽  
Water Bodies ◽  
The European Union ◽  
Nitrogen And Phosphorus ◽  
Member States ◽  
Environmental Objectives

<p>Continental water ecosystems and human water uses may be jeopardized by degradation of water quality.  To prevent this degradation, the maximum concentration of pollutants for freshwater bodies may need to be set in the legislation. In some cases, the actions needed to achieve those environmental objectives may be technically challenging or financially overburdening. In the case of the European Union (EU), the Water Framework Directive (WFD, Article 4) requires the achievement of the good status of water bodies but allows for the declaration of exemptions due to lack of technical feasibility or disproportionate costs. Twenty years after the WFD approval, the conditions to declare exemptions remain unclear and in practice their declaration  is highly discretional.</p><p>The extant scientific literature suggests several methods to formulate the justification of exemptions. Although the methodologies are diverse, they all require to select a threshold (e.g. in terms of cost disproportionality) above which a relaxation of the environmental objectives may be accepted. This threshold should be uniform across the EU River Basin Districts in order to guarantee a fair distribution of efforts across Member States. To date, however, there are very few studies that compare the application of exemptions in different regions to assess the uniformity of approaches to the declaration of exceptions.</p><p>When defining actions to achieve the good status of water bodies, the quantification of the different pressures, their interactions and the effects on receiving water bodies can be challenging. In the case of physico-chemical pollutants, however, it can be easier to define policy actions as pressures can be quantified (point loads of wastewater treatment plants, diffuse loads emanated by different land uses) and the evolution in receiving waters can be modelled.</p><p>In our research, we analyzed over one thousand water bodies in the River Basin Districts of five different Member States of the European Union (Estonia, a transboundary Ireland-United Kingdom basin, Italy, Spain and Portugal), using the available databases on Digital Elevation Models (Copernicus EU-DEM), land use (CORINE land cover), urban pressures (European Urban Wastewater Treatment Directive dissemination platform and reported data), runoff and gauged flows (Water Information System for Europe, national gauging networks) and WFD exemption databases. Each water body was characterized according to the level of nitrogen and phosphorus pressures deriving from point and diffuse loads, and the declaration of exemptions to the environmental objectives for those nutrients. The exemption threshold is assessed for each River Basin District, allowing for a critical review of the different water policies in this significant aspect of the Water Framework Directive implementation.</p>

scholarly journals Αποτελέσματα εισοδήματος στην οριακή επιθυμία για πληρωμή μέσα στο πλαίσιο του κοινοτικού πλαισίου για τους υδάτινους πόρους

2017 ◽  
Author(s):  
Εμμανουήλ Τυλλιανάκης
Keyword(s):  
Water Framework Directive ◽  
Water Environment ◽  
Ecological Status ◽  
River Basin Management ◽  
Water Bodies ◽  
Public Consultation ◽  
Scientific Models ◽  
The European Union ◽  
Human Welfare ◽  
The Impact

This thesis aims to analyse and comment on the impact of large agri-environmental policy directives in the welfare of European citizens. THe focus of this thesis is on the Water Framework Directive which had as its orearching target to achieve Good Ecological Status for all European water bodies. The directive set out an integrated river basin management framework which in turn was at the juristiction of regional bodies to implement. The purpose of the theisis is to offer a balanced approach from both the social and the economic side of assessing such large pieces of legislation, without turning a blind eye to its shortcomings, while aknowledging its importance to the European Union goals. The approach of the thesis is anthropocentric, which is not always the case in neoclassical economic theory, which has influenced the design of the Water Framework Directive. The thesis prides itself in its analysis of the impacts of the directive during its design state and its implementation state as well. Finally, the thesis comments on its findings from the viewpoints of physical, social and economic sciences.In particular, the thesis attempts to answer the following questions:1. What are the real implications of large pieces of policy work such as the Water Framework Directive on human welfare?2. Which is, if any, the impact and value of scientific models in the design of case-specific agri-environmental policies for river basins?3. Are such directives cost-effective in their implementation in the regional level?4. Who benefits more from these directives, poorer or richer househlods?5. If individual perceptions on risk are taken into consideration, how well do these reflect the true threats to the water environment, and how that affects public consultation in the preparatory phase of such directives?6. How do European-set ecologcal and environmental indexes for the waters help European citizens realise the true threats to the water bodies in their region?

scholarly journals Estimation of Chlorophyll-a Concentrations in Small Water Bodies: Comparison of Fused Gaofen-6 and Sentinel-2 Sensors

2022 ◽  
Vol 14 (1) ◽  
pp. 229
Author(s):  
Jiarui Shi ◽  
Qian Shen ◽  
Yue Yao ◽  
Junsheng Li ◽  
Fu Chen ◽  
...  
Keyword(s):  
Machine Learning ◽  
Chlorophyll A ◽  
Water Bodies ◽  
Gradient Boosting ◽  
Learning Models ◽  
Small Water ◽  
Extreme Gradient Boosting ◽  
Machine Learning Models ◽  
Sentinel 2 ◽  
Small Water Bodies

Chlorophyll-a concentrations in water bodies are one of the most important environmental evaluation indicators in monitoring the water environment. Small water bodies include headwater streams, springs, ditches, flushes, small lakes, and ponds, which represent important freshwater resources. However, the relatively narrow and fragmented nature of small water bodies makes it difficult to monitor chlorophyll-a via medium-resolution remote sensing. In the present study, we first fused Gaofen-6 (a new Chinese satellite) images to obtain 2 m resolution images with 8 bands, which was approved as a good data source for Chlorophyll-a monitoring in small water bodies as Sentinel-2. Further, we compared five semi-empirical and four machine learning models to estimate chlorophyll-a concentrations via simulated reflectance using fused Gaofen-6 and Sentinel-2 spectral response function. The results showed that the extreme gradient boosting tree model (one of the machine learning models) is the most accurate. The mean relative error (MRE) was 9.03%, and the root-mean-square error (RMSE) was 4.5 mg/m3 for the Sentinel-2 sensor, while for the fused Gaofen-6 image, MRE was 6.73%, and RMSE was 3.26 mg/m3. Thus, both fused Gaofen-6 and Sentinel-2 could estimate the chlorophyll-a concentrations in small water bodies. Since the fused Gaofen-6 exhibited a higher spatial resolution and Sentinel-2 exhibited a higher temporal resolution.

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