The objective of ESA’s SEOM Programme Sen2Coral is the preparation of the exploitation of the Sentinel-2 mission for coral reefs by developing and validating appropriate, open source algorithm available for the community.
The project objectives are the scientific exploitation and validation of the Sentinel-2 Multispectral Instrument (MSI) for mapping (habitat, bathymetry, and water quality) and detection change for coral reef health assessment and monitoring, and algorithm development dedicated to Sentinel-2 capabilities to satisfying these objectives.
- A critical analysis of feedback from scientists and institutions collected through consultations in ESA and Third Party workshops, symposia and conferences
- Proposal of potential observation scenarii for Sentinel-2 in terms of required spatial coverage and repeat cycle considering user requirements, existing observation initiatives and synergy with other sensors (Landsat, SPOT sensor families)
- Identifying scientific priority areas and providing guidance for future scientific data exploitation projects
This builds on the work presented in the paper authored by John Hedley, Chris Roelfsema, Benjamin Koetz and Stuart Phinn (2012), “Capability of the Sentinel 2 mission for tropical coral reef mapping and coral bleaching detection”, Remote Sensing of the Environment, 120, 145-155.
Sentinel 2 Images
To address the extremely interesting and challenging questions posed by this project a consortium of contractors with appropriate background knowledge and skills has been assembled. The consortium comprises:
In line with the Copernicus policy, the project has been structured with the purpose of offering to the community of users free-access to reliable and up-to-date Coral health information. It is centred on an Advisory Group, the Science Team, assisted by a Technical Team tasked to provide registered stakeholders with a number of services approved by the Project Management.
Science Advisory Group
The consortium is complimented by a science team of consultants and partners who are recognised international scientists in the field. The members of the team are:
- Dr. John Hedley (Numerical Optics Limited, UK)
- Dr. Claudia Giardino (CNR-IREA, Italy)
- Dr. Vittorio Brando (CNR-IREA, Italy)
- Dr. Tiit Kutser (University of Tartu, Estonian Marine Institute)
- Dr. Antoine Collin (EPHE Sorbonne, France)
- Professor Peter Mumby (University of Queensland, Australia)
- Professor Stuart Phinn (University of Queensland, Australia)
- Dr. Chris Roelfsema (University of Queensland, Australia)
The Science Advisory Group is supported by a Technical team tasked with collecting, validating, formatting and distributing the data, software and products elaborated in the course of the project.
The Technical Team comprises a number of key engineers, amongst whom the technical tasks have been distributed as follows
- Project management: Jean Laporte (ARGANS Ltd)
- Project conceptual supervision: Dr FR Martin-Lauzer (ARGANS Ltd)
- Validation and management of satellite imagery: Jan Jackson (ARGANS Ltd):
- Software development: Dr Stephen Emsley (ARGANS Ltd.)
- Image processing: Romain Serra (ARGANS Ltd)
- Production of charts: Henri Dolou, FIG/IHO/ICA Cat. A (ARGANS Ltd):
- Software package & ATBD manual: Julien Malik, Philippe Bryere, CS-SI
The Stakeholders are EO scientists who represent the community of users. Once registered in Sen2Coral and providing they acknowledge the Project IPR routines, they may
- have privileged access to Sen2Coral data, images and products;
- place standing orders to collect Sentinel 2 mages of coral areas of interest, not limited to the Sen2Coral initial four sites;
- post images and publications on the Sen2Coral website likely to contribute to the improvement of the future Sentinel 2 World Coral Observatory;
- supplement, and eventually participate in, the Science Advisory Group.
The provisional list of Registered Stakeholders (to be confirmed) is as follows:
- Dr Serge Andrefouet, IRD Centre, New Caledonia
- Professor Claude Payri, IRD Centre, New Caledonia
- Dr Thomas A. Oliver, Pacific Islands Fisheries Science Centre, NOAA
- Dr Britta Schaffelke, Australian Institute of Marine Science
- Eric Hochberg, Bermuda Institute of Ocean Sciences
This list is not closed and any further peer-to-peer co-operation amongst self-interested users is welcome.
The degradation of coral reefs is a fact, with 55% of reefs being affected by overfishing and destructive fishing methods, which as the most pervasive threats, whereas 25% of reefs are affected by coastal development and pollution from land, including nutrients from farming and sewage, while one tenth suffer from marine-based pollution (local pressures are most severe in South-East Asia, where nearly 95 per cent of coral reefs are threatened).
In addition the coral reefs’ ecosystems appear to be the first to respond to global climate changes, such as increased sea surface temperature (SST), ultraviolet radiation (UV) and acidification of seawater that results from higher levels of atmospheric CO2 concentration.
Sentinel-2 MSI Data Acquisition
- 10 meter spatial resolution allowing improvement in visual interpretation of reef features, classification accuracy and bathymetry.
- Additional water penetrating optical band improving consistency under varying water conditions, reducing uncertainty in bottom type and bathymetric mapping, deeper bathymetric accuracy and ability to determine water optical properties.
- Additional NIR/SWIR bands enabling more consistent and accurate determination of atmospheric and surface glint correction.
- Short re-visit time enabling the use of image series to determine fundamental uncertainties for change detection.
- Addresses the current limited remote sensing acquisition plan covering the coast areas.
Algorithm Development & Data Processing
The objective “to develop and validate new algorithms relevant for coral reef monitoring based on Sentinel-2 observations” will be addressed by parameterising existing models for processing hyper-spectral & multi-spectral data and developing pre-processors for these models to build Sentinel-2 data processing algorithms for the retrieval of coral reefs’ static and dynamic characteristics. The code developed will be made available open source.
Validation & uncertainty analysis will involve both comparing Sentinel MSI performance versus Landsat 8 on coral reef mapping objectives and comparing coral reef monitoring products against in situ data from reef sites representative of different composition and structure.
To design, verify and validate three coral reef monitoring products making the best use of Sentinel-2 MSI mission characteristics:
- Habitat mapping of coral reefs
- Coral reef change detection
- Bathymetry over coral reefs
A 6 day field campaign around the South Pacific island of Fatu Huku was undertaken by French scientist Antoine Collin to collect in-situ data to test and validate the capabilities of the Sentinel-2 satellite to monitor coral reef bleaching.
Fatu Huku Island in French Polynesia was chosen as the survey site because of the presence of developed coral reefs and it is an area water temperatures are high as a result of the current El Niño event. During the survey, water temperature exceeding 30°C were recorded and coral bleaching, the expulsion of the symbiotic algae that provide energy from sunlight to the coral, was observed to be taking place.
Data collected from this field campaign complements archives of in-situ data collected over previous years from coral reef sites across the globe such as at Heron Island and Lizard Island, in Australia, and reefs around Palau, in the western Pacific Ocean.
The world's major coral reef science meeting, the International Coral Reef Symposium (ICRS), is held every four years. Several of the Sen2Coral Science Team attended and gave presentations. Vittorio Brando presented preliminary results from the project. This...read more
A presentation of this report including detailed analysis (PDF, 60MB) is available hereread more
Author: Dr. F.R. Martin-Lauzer (ARGANS Ltd & ACRI) Under preparation - currently in draft form and unavailable.read more
Author: Jean Laporteread more
A 6 day field campaign around the South Pacific island of Fatu Huku was undertaken by French scientist Antoine Collin to collect in-situ data to test and validate the capabilities of the Sentinel-2 satellite to monitor coral reef bleaching. Fatu Huku Island in French...read more
During its March 2016 survey of the Lampi Island Marine Park combining Sentinel 2 satellite data and field observations, CNR-IREA could observe the progress of coral bleaching in the Adaman Sea and the disastrous effects of blast fishing onto the environment....read more
Aimed at monitoring the coral reef decline worldwide in agreement with the following scientific approach, the ESA Sen2Coral project of health observatory exploits the Sentinel 2 satellites’ multispectral performances, global coverage, high resolution, frequent...read more