Global Monitoring For Environment And Security Research Articles

Investigation of Carbon Dioxide Variations in Selected Points in Nigeria Using Neural Network Model

Atmospheric pollution due to carbon dioxide emission from different fossil fuels and deforestations are considered as a great and important international challenge to the societies. This study is to investigate carbon dioxide (CO2) distributions in selected points in Nigeria using neural network. Neural network model were used to estimate daily values of carbon dioxide, study spatial temporal variations of carbon dioxide, and study the annual variations of estimated and observed carbon dioxide in Nigeria. The study areas used in this work are thirty six (36) points location over Nigeria. The data used in this work is a satellite carbon dioxide () data were obtained from Global Monitoring for Environment and Security (GMES) under the programme of Monitoring Atmospheric Composition And Climate (MACC) www.gmes-atmosphere.eu/data between 2009-2014. The neural network architecture used comprises of three main layers; an input layer, a hidden layer and an output layer. Four input data were considered which include year, day of year (DOY) representing the time, latitude and longitude. Twenty hidden neurons were employed, while the output is the desired data of carbon dioxide. The results show that the increase in trend of CO2 in dry season in every part of the country is on yearly bases. In the wet season, the concentration of CO2 in Nigeria is not as much as in the dry season case, probably due to absorption of the gas by precipitation. The continuous annual increase of CO2 distribution suggests continuous increase of the greenhouse gas in Nigeria. This reveals continuous contribution of CO2 in Nigeria. The similarity in the estimated and observed signatures reveals that neural network model performance were excellent and efficient in determination of spatial distribution of CO2, thereby proving to be useful tool in modeling the greenhouse gases. The results show that neural network model has the capacity of investigating greenhouse gases variations in Nigeria.

Aplicación de imágenes Sentinel-1 y Sentinel-2 en la detección y delineación de información de crisis de desastres naturales en el marco de los servicios Copernicus EMS

<p>This study shows the inclusion of Sentinel-1 and Sentinel-2 images in the workflows to obtain of crisis information of different types of events and their applicability in the detection and monitoring of those events. Sentinel is an Earth Observation (EO) program that is currently being developed by the European Space Agency (ESA) in the scope of the Copernicus program operative since April 2012, formerly known as Global Monitoring for Environment and Security (GMES). This program comprises six missions, out of which three are active, Sentinel-1 that provides radar images, Sentinel-.2 providing High Resolution optical images and Sentinel-3 developed to support GMES ocean, land, atmospheric, emergency, security and cryospheric applications. The present paper describes the use of Sentinel-1 radar to detect and delineate flooded areas, and the MultiTemporal Coherence (MTC) analysis applied with pre and post-event images to delimit and monitor burnt areas and lava flows. With respect to Sentinel-2, its high spectral resolution bands allowed the delineation of burnt areas by calculating differences of vegetation and burnt indices using pre and postevent images. Results using Sentinel-1 and Sentinel-2 data were compared with results using higher spatial resolution images, both optical and radar. In all cases, the usability of Sentinel images was proven.</p>

Extraction and Validation of Geomorphological Features from EU-DEM in The Vicinity of the Mygdonia Basin, Northern Greece

The European Union Digital Elevation Model (EU-DEM) is a relatively new, hybrid elevation product, principally based on SRTM DEM and ASTER GDEM data, but also on publically available Russian topographic maps for regions north of 60° N. More specifically, EU-DEM is a Digital Surface Model (DSM) over Europe from the Global Monitoring for Environment and Security (GMES) Reference Data Access (RDA) project - a realisation of the Copernicus (former GMES) programme, managed by the European Commission/DG Enterprise and Industry. Even if EU-DEM is indeed more reliable in terms of elevation accuracy than its constituents, it ought to be noted that it is not representative of the original elevation measurements, but is rather a secondary (mathematical) product. Therefore, for specific applications, such as those of geomorphological interest, artefacts may be induced. To this end, the purpose of this paper is to investigate the performance of EU-DEM for geomorphological applications and compare it against other available datasets, i.e. topographic maps and (almost) global DEMs such as SRTM, ASTER-GDEM and WorldDEM™. This initial investigation is carried out in Central Macedonia, Northern Greece, in the vicinity of the Mygdonia basin, which corresponds to an area of particular interest for several geoscience applications. This area has also been serving as a test site for the systematic validation of DEMs for more than a decade. Consequently, extensive elevation datasets and experience have been accumulated over the years, rendering the evaluation of new elevation products a coherent and useful exercise on a local to regional scale. In this context, relief classification, drainage basin delineation, slope and slope aspect, as well as extraction and classification of drainage network are performed and validated among the aforementioned elevation sources. The achieved results focus on qualitative and quantitative aspects of automatic geomorphological feature extraction from EU-DEM at a water basin level, with the use of Geographical Information Systems (GIS).

PENGENALAN CITRA SATELIT SENTINEL-2 UNTUK PEMETAAN KELAUTAN

RECOGNITION AND UTILIZATION OF SATELLITE IMAGE SENTINEL-2 FOR MARINE MAPPING. Sentinel-2 is a satellite launched by a collaboration between The European Commission and the European Space Agency in the Global Monitoring for Environment and Security (GMES) program. The satellite has a mission to scan the Earth’s surface simultaneously at an angle of 180 each satellite with a 5-day temporal resolution with the same appearance on the equator and has a spatial resolution of 10 m, 20 m, and 60 m. There are 13 multispectral channels including VNIR and SWIR. Four channels with 10 m spatial resolution adapt with SPOT 4/5 and user’s comply requirements for land cover classification. Six channels with 20 m spatial resolution becomes a requirement for other Level 2 processing parameters. Channels with 60 m spatial resolution are specified for atmospheric correction and cloud filtering (443 nm for aerosols, 940 nm for moisture, and 1375 for thin cloud detection). Based on these specifications, Sentinel-2 can be an alternative for users to obtain image data with spatial, temporal, radiometric, and spectral resolution is better than SPOT and Landsat. Sentinel-2 can be downloaded for free and easy by the general public. The existence of image by Sentinel-2 is expected to be used optimally, especially for remote sensing analysis in marine field.

Changes of urbanised landscape identified and assessed by the Urban Atlas data: Case study of Prague and Bratislava

Identification, analysis and assessment of changes in the urbanised landscape, one of the most conspicuous transforming parts of earth surfaces, has become the topic of numerous research projects. However, there is still a lack of compatible data suitable for the generation of topical information about the urbanised landscape and its changes at different scales. An important contribution in this sense is the Urban Atlas (UA) Project pursued under the GMES (Global Monitoring for Environment and Security)/Copernicus Land (GIO land) Programme auspiced by the European Commission. The aim of this study is to document, examine and compare land use/cover change (LUCC) of the LUZs (Large Urban Zones) of Bratislava and Prague in 2006–2012 by means of the UA data and show how these changes are captured in official statistical data. Results confirmed the present trends in modern industrial cities dominating by transforming the agricultural land into residential and industrial areas. Dispersion of the urban fabric into locations previously used for agriculture was mostly widespread in LUZ Prague (1,718ha). This trend has also been partially confirmed by the change of agricultural land in favour of construction sites, the most pronounced one in LUZ Bratislava (580ha). Assessment and comparisons of LUCC changes of LUZs Bratislava and Prague proved that combining the UA data and official statistical data has a great potential for insight into the dynamics of the urbanised landscape of Europe.

Predicciones de calidad del aire a alta resolución en el Mediterráneo occi-dental para los proyectos MACC, MACC-II y MACC-III

The European Earth observation programme Copernicus, formerly known as GMES (Global Monitoring for Environment and Security) is establishing a core global and regional environmental atmospheric service as a component of the Europe’s Copernicus/GMES initiative through successive R&D projects led by ECMWF (European Center for Medium-range Weather Forecasting) and funded by the 6th and 7th European Framework Programme for Research and Horizon 2020 Programme: GEMS, MACC, MACC-II and MACC-III. AEMET (Spanish State Meteorological Agency) has participated in the projects MACC and MACC-II and continues participating in MACC-III (http://atmosphere.copernicus.eu). AEMET has contributed to those projects by generating high-resolution (0.05 degrees) daily air-quality forecasts for the Western Mediterranean up to 48 hours aiming to analyse the dependence of the quality of forecasts on resolution. We monitor the evolution of different chemical species such as NO2, O3, CO y SO2 at surface and different vertical levels using the global model MOCAGE and the MACC Regional Ensemble forecasts as chemical boundary conditions. We will show different case-studies, where the considered chemical species present high values and will show a validation of the air-quality by comparing to some of the available air-quality observations (EMEP/GAW, regional -autonomous communities- and local -city councils- air-quality monitoring networks) over the forecast domain. The aim of our participation in these projects is helping to improve the understanding of the processes involved in the air-quality forecast in the Mediterranean where special factors such as highly populated areas together with an intense solar radiation make air-quality forecast-ing particularly challenging.

Monthly Time-Step Erosion Risk Monitoring of Ishmi-Erzeni Watershed, Albania, Using the G2 Model

In this study, soil erosion was mapped in Ishmi-Erzeni watershed, Albania, using the G2 model. The G2 model has been proposed as an agri-environmental service by the Global Monitoring for Environment and Security (GMES) initiative (now Copernicus programme). Based on the principles of the Universal Soil Loss Equation (USLE), G2 provides maps of actual soil loss at a monthly time-step. The main innovations of the model with regard to previous USLE family models are as follows: the introduction of a ‘storm factor’, which differentiates rainfall erosivity (R factor) per month when detailed rain intensity records are not available; the use of standardised biophysical parameters derived from satellite image time series in combination with land use information for calculating the vegetation retention factor (denoted here as V factor, corresponding to C factor of USLE); and the use of satellite imagery for calculating a new factor, namely the slope intercept factor (denoted as I factor), which expresses landscape feature alterations, thus functioning as corrective to the topographic influence factor (denoted here as T factor, the slope length and steepness (LS) factor of USLE). The model was originally implemented in the cross-border Strymonas river basin and on the island of Crete after revision; in both cases with encouraging results. The G2 model follows a data-driven methodology, while providing alternatives for all factor estimations with moderate data requirements. For the model application in the Ishmi-Erzeni watershed (covering 2200 km2), rainfall data were collected from ten weather stations, and soil properties were measured from sampling at 47 locations. Vegetation layers were downloaded from the GMES portal, while land use information was extracted from a Landsat-7 TM image. Finally, terrain properties were calculated from a 250-m digital elevation model (DEM) of the area. The G2 model showed Ishmi-Erzeni to have moderate soil erosion, with a mean annual soil loss estimated to be 6.5 t/ha; however, 18 % of the area is facing an annual risk of soil removal more than 10 t/ha, which is considered to be a sustainable threshold for Albania. Winter months appear to be the most risky, with all months contributing substantially to the annual erosion rate (i.e. between 4 and 12 % each). Areas of coniferous and mixed forests, together with mountainous agricultural land, appear to be the most risky land uses. In conclusion, the G2 model proved to be useful and efficient for predicting erosion at monthly time-steps for all land uses in the Ishmi-Erzeni watershed. Future research will focus on an Albania-wide erosion mapping task, using the G2 model.

Sentinel Satellites Initiate New Era in Earth Observation

With the European Space Agency's (ESA) Sentinel‐1A satellite expected to enter into its operational phase later this summer, it ushers in a new series of Earth observation satellites. The first generation of the fleet of satellites, which will total 20 when all are launched, will comprise “the most comprehensive Earth observation system worldwide,” according to Josef Aschbacher, head of program planning and coordination for ESA's Earth Observation Programs directorate. The satellites are a key part of Copernicus, the European Earth Observation Program that from 1998 to 2012 was called the Global Monitoring for Environment and Security (GMES) program.

15 years of processing and dissemination of SPOT-VEGETATION products

Throughout the VEGETATION programme, the Flemish Institute for Technological Research (VITO) uninterruptedly hosted the prime user segment of both VEGETATION 1 and VEGETATION 2 multispectral instruments on board the Satellite Pour l’Observation de la Terre 4 (SPOT 4) and SPOT 5 satellites. Operational since the launch of SPOT 4 in March 1998, and foreseen to continue at least until the end of the SPOT 5 mission (anticipated in spring 2014), this user segment comprises a processing facility (PF), actively receiving, processing, correcting, archiving, and distributing the VEGETATION data and derived added-value products. First and foremost, the VEGETATION programme has been serving the needs of operational users – both institutional and commercial – requesting data in near-real time. However, scientific and educational users too benefited significantly, in particular from VEGETATION’s unique time series of the Earth’s land cover, and more specifically the vegetation cover. Over the years, the centralized archive houses processed data covering the equivalent of 11,000 times the Earth’s surface, and delivered more than 50 terapixels to around 10.000 users. As such, VEGETATION’s mission is a prime example of what Europe wants to achieve through the Global Monitoring for Environment and Security (GMES) initiative: truly operational services providing reliable and up-to-date information.This article describes the processing facility, the way the data and products are archived, the different dissemination channels as well as the data policy adopted and the users served. One of the recent evolutions, the development of an entirely new product distribution facility (PDF), implemented as part of the Project for On-Board Autonomy – Vegetation (PROBA-V) user segment is discussed.

The GMES Space Component Data Access System: Harmonizing Earth Observation Products Flows and Services for GMES

The Global Monitoring for Environment and Security (GMES) Space Component relies on a constellation of dedicated space missions (called the Sentinels, scheduled for first launch by 2013), as well as on a set of space missions not dedicated to GMES but contributing to it. In charge of optimizing access and usability of the available space-based remote sensing resources for the pre-operations, the European Space Agency has elaborated the GMES Space Component Data Access concept, implementing mechanisms for aligning the data access across the GMES contributing missions, harmonising user information services, ordering and data delivery processes, and monitoring the data and service quality. Overall, this is a large-scale integrated system of systems, involving today more than 10 different ground segments and 20 space missions, serving users according to different modes of operations derived from pre-identified users' needs.

Aerosols for Concentrating Solar Electricity Production Forecasts: Requirement Quantification and ECMWF/MACC Aerosol Forecast Assessment

The potential for transferring a larger share of our energy supply toward renewable energy is a widely discussed goal in society, economics, environment, and climate-related programs. For a larger share of electricity to come from fluctuating solar and wind energy-based electricity, production forecasts are required to ensure successful grid integration. Concentrating solar power holds the potential to make the fluctuating solar electricity a dispatchable resource by using both heat storage systems and solar production forecasts based on a reliable weather prediction. These solar technologies exploit the direct irradiance at the surface, which is a quantity very dependent on the aerosol extinction with values up to 100%. Results from present-day numerical weather forecasts are inadequate, as they generally use climatologies for dealing with aerosol extinction. Therefore, meteorological forecasts have to be extended by chemical weather forecasts. The paper aims at quantifying on a global scale the question of whether and where daily mean or hourly forecasts are required, or if persistence is sufficient in some regions. It assesses the performance of recently introduced NWP aerosol schemes by using the ECMWF/Monitoring Atmospheric Composition and Climate (MACC) forecast, which is a preparatory activity for the upcoming European Global Monitoring for Environment and Security (GMES) Atmosphere Service.

Cooled infrared filters and dichroics for the sea and land surface temperature radiometer

The sea and land surface temperature radiometer (SLSTR) is a nine-channel visible and infrared high-precision radiometer designed to provide climate data of global sea and land surface temperatures. The SLSTR payload is destined to fly on the Ocean and Medium-Resolution Land Mission for the ESA/EU global monitoring for environment and security (GMES) programme Sentinel-3 mission to measure the sea and land temperature and topography for near real-time environmental and atmospheric climate monitoring of the Earth. In this paper we describe the optical layout of infrared optics in the instrument, the spectral thin-film multilayer design, and the system channel throughput analysis for the combined interference filter and dichroic beam splitter coatings to discriminate wavelengths at 3.74, 10.85, 12.0 μm. The rationale for selection of thin-film materials, the deposition technique, and environmental testing, inclusive of humidity, thermal cycling, and ionizing radiation testing are also described.

Predictions for oil slicks detected from satellite images using MyOcean forecasting data

Abstract. The pan-European capacity for the Ocean Monitoring and Forecasting (MyOcean) Marine Core Service, implementing the Global Monitoring for Environment and Security (GMES) objectives, targets the provision of ocean state observations from various platforms and analysis and forecasting products to assist, among other downscaling activities, the needs of the operational response to marine safety, particularly concerning oil spills. The MEDSLIK oil spill and trajectory prediction system makes use of the MyOcean regional and Cyprus Coastal Ocean Forecasting and Observing System (CYCOFOS) downscaled forecasting products for operational application in the Mediterranean and pre-operational use in the Black Sea. Advanced Synthetic Aperture Radar (ASAR) satellite remote sensing images from the European Space Agency (ESA) and European Maritime Safety Agency CleanSeaNet (EMSA-CSN) provide the means for routine monitoring of the southern European seas for the detection of illegal oil discharges. MEDSLIK offers various ways, to be described in this paper, of coupling the MyOcean forecasting data with ASAR images to provide both forecasts and hindcasts for such remotely observed oil slicks. The main concern will be the drift of the oil slick and also, in the case of the forecast mode, its diffusive spreading, although some attempt is also made to estimate the changes in the state of the oil. The successful link of the satellite-detected oil slicks with their operational predictions using the MyOcean products contributes to the operational response chain and the strengthening of maritime safety for accidental or illegal spills, in implementation of the Mediterranean Decision Support System for Marine Safety (MEDESS-4MS) regarding oil spills.

High and Ultra-High resolution processing of satellite Sea Surface Temperature data over Southern European Seas in the framework of MyOcean project

In the framework of the GMES (Global Monitoring for Environment and Security) MyOcean projects, funded by the European Commission, different remotely-sensed Sea Surface Temperature (SST) supercollated (L3S) and interpolated (L4) data are produced and distributed in near-real time by the Consiglio Nazionale delle Ricerche – Istituto di Scienze dell'Atmosfera e del Clima – Gruppo di Oceanografia da Satellite (CNR). These SST products are based on the night-time images collected by the infrared sensors mounted on different satellite platforms and cover the whole Southern European Seas (i.e. the Mediterranean Sea, including the eastern Atlantic Ocean, and the Black Sea). The CNR processing chains include several modules, from the data extraction and preliminary quality control, to cloudy pixel removal and satellite images collating/merging up to L3S. A two-step algorithm finally allows to interpolate SST data at High (HR 1/16°) and Ultra-High (UHR 1/100°) spatial resolution. The basic design and the main algorithms used in MyOcean processing chains are described hereafter. A validation of the HR super-collating procedure developed during MyOcean is presented. The Mediterranean HR and UHR L3S and L4 operational products have then been validated vs in situ SST measurements from drifting buoys, covering two years of data (2010–2011). The validation includes a comparison between the UHR CNR L4 and the G1SST L4 developed by Chao et al. (2009).

Global reactive gases forecasts and reanalysis in the MACC project

The EU FP7 projects MACC (Monitoring Atmospheric Composition and Climate, 2009–2011) prepared for the operational Global Monitoring for Environment and Security (GMES) atmospheric core service on greenhouse gases, reactive gases and aerosols which is envisaged to start in 2014. This paper describes the data assimilation and modelling system which has been implemented for global monitoring of reactive gases in the troposphere and stratosphere. The MACC reactive gases system uses a coupling software to integrate the Model for Ozone And Related Tracers, version 3 (MOZART-3) chemistry transport model with the Integrated Forecast System (IFS) of the European Centre for Medium-range Weather Forecasts (ECMWF). The focus is placed on the tropospheric simulations with this MACC-IFS-MOZ model. The MACC reanalysis (2003–2010) and the forecasts performed in near real time (NRT) benefit from the multi-sensor approach for data assimilation of total columns, tropospheric columns and vertically resolved observations of ozone, CO and NO2. Daily biomass burning emissions are integrated in real time using the global fire assimilation system (GFAS) that was developed within MACC. Other emissions are taken from a state-of-the-art global inventory that was developed across several EU projects. The MACC reanalysis and tracer forecasts are routinely evaluated with ground-based and airborne in-situ observations and independent satellite retrieval products. We present the system set-up for reactive gases, give an overview on the service and technical developments during the project, and indicate how MACC global reactive gases products could provide information on non-CO2 greenhouse gases.

Error analysis of subpixel lava temperature measurements using infrared remotely sensed data

When remote sensing users are asked to define their requirements for a new sensor, the big question that always arises is: will the technical specifications meet the scientific requirements? Herein, we discuss quantitative relationships between instrumental spectral and radiometric characteristics and data exploitable for lava flow subpixel temperature analysis. This study was funded within the framework of ESA activities for the IR GMES (Global Monitoring for Environment and Security) element mission requirements in 2005. Subpixel temperature retrieval from satellite infrared data is a well-established method that is well documented in the remote sensing literature. However there is little attention paid to the error analysis on estimated parameters due to atmospheric correction and radiometric accuracy of the sensor. In this study, we suggest the best spectral bands combination to estimate subpixel temperature parameters. We also demonstrate that poor atmospheric corrections may vanish the effectiveness of the most radiometrically accurate instrument.

OBJECT BASED IMAGE ANALYSIS TO SUPPORT ENVIRONMENTAL MONITORING UNDER THE EUROPEAN HABITAT DIRECTIVE: A CASE STUDY FROM DECOVER

Abstract. DeCOVER serves as a national extension of the European Global Monitoring for Environment and Security (GMES) initiative. It was initiated to develop land cover information services adapted to German user needs. One of its three service developments pillars is the application of Remote Sensing to support environmental monitoring schemes under the European Habitats Directive.Within two DeCOVER test sites located in North-Rhine Westphalia/Germany an object-based indicator classification approach is currently being developed to monitor heath habitats of importance under the Habitats Directive. While many previous Remote Sensing projects have focused on the discrete classification of habitat types to replace fieldwork, our approach is embedded in a strong operational context to a) focus and direct fieldwork efforts by pre-field visit assessment of habitat changes (change detection) and b) support fieldwork by contributing quality parameters and GIS-ready geometries. Using Geoeye satellite data (VHR component) and RapidEye satellite images (Multi-temporal HR component) together with existing habitat and biotope maps (knowledge and post-classification component) an image analysis approach is realised using object-based classification routines based on data mining tools to derive training information. To extract meaningful objects of heath-, sand- and grassland from the VHR-data, training sample areas have to be assigned. Thresholds and appropriate features for describing these samples are analysed by statistical algorithms and are used in the following classification. A multi-temporal approach for the acquisition of tree habitat areas integrates two RapidEye scenes into the classification process. To validate classification accuracies and potential transects were sampled in the field and analyzed for their structural composition using top view field photos of 1m2. First results demonstrate the realistic option to directly support the fieldwork or reduce its post-processing costs.

Quantifying the value of environmental information to society

Socio‐Economic Benefits From the Use of Earth Observation; Ispra, Italy, 11–13 July 2011 Many large space‐or ground‐based Earth observation systems, such as Global Monitoring for Environment and Security (GMES) and Landsat, are justified by citing their benefits to scientific knowledge and their impacts on government decisions about environmental issues. These justifications attempt to quantify the lives saved, losses avoided, or economic benefits gained. Each justification is made on an ad hoc basis, and the approach used in one case rarely applies to another. In July 2011 a workshop was held at the European Commission Joint Research Centre in Italy to consider whether broadly applicable methodologies could be developed that could be consistently used for assessing the value of large‐scale observation and information systems.

SENTINEL-2 LEVEL 1 PRODUCTS AND IMAGE PROCESSING PERFORMANCES

Abstract. In partnership with the European Commission and in the frame of the Global Monitoring for Environment and Security (GMES) program, the European Space Agency (ESA) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbit. While ensuring data continuity of former SPOT and LANDSAT multi-spectral missions, Sentinel-2 will also offer wide improvements such as a unique combination of global coverage with a wide field of view (290 km), a high revisit (5 days with two satellites), a high resolution (10 m, 20 m and 60 m) and multi-spectral imagery (13 spectral bands in visible and shortwave infra-red domains). In this context, the Centre National d'Etudes Spatiales (CNES) supports ESA to define the system image products and to prototype the relevant image processing techniques. This paper offers, first, an overview of the Sentinel-2 system and then, introduces the image products delivered by the ground processing: the Level-0 and Level-1A are system products which correspond to respectively raw compressed and uncompressed data (limited to internal calibration purposes), the Level-1B is the first public product: it comprises radiometric corrections (dark signal, pixels response non uniformity, crosstalk, defective pixels, restoration, and binning for 60 m bands); and an enhanced physical geometric model appended to the product but not applied, the Level-1C provides ortho-rectified top of atmosphere reflectance with a sub-pixel multi-spectral and multi-date registration; a cloud and land/water mask is associated to the product. Note that the cloud mask also provides an indication about cirrus. The ground sampling distance of Level-1C product will be 10 m, 20 m or 60 m according to the band. The final Level-1C product is tiled following a pre-defined grid of 100x100 km2, based on UTM/WGS84 reference frame. The stringent image quality requirements are also described, in particular the geo-location accuracy for both absolute (better than 12.5 m) and multi-temporal (better than 0.3 pixels) cases. Then, the prototyped image processing techniques (both radiometric and geometric) will be addressed. The radiometric corrections will be first introduced. They consist mainly in dark signal and detector relative sensitivity correction, crosstalk correction and MTF restoration. Then, a special focus will be done on the geometric corrections. In particular the innovative method of automatic enhancement of the geometric physical model will be detailed. This method takes advantage of a Global Reference Image database, perfectly geo-referenced, to correct the physical geometric model of each image taken. The processing is based on an automatic image matching process which provides accurate ground control points between a given band of the image to refine and a reference image, allowing to dynamically calibrate the viewing model. The generation of the Global Reference Image database made of Sentinel-2 pre-calibrated mono-spectral images will be also addressed. In order to perform independent validation of the prototyping activity, an image simulator dedicated to Sentinel-2 has been set up. Thanks to this, a set of images have been simulated from various source images and combining different acquisition conditions and landscapes (mountains, deserts, cities …). Given disturbances have been also simulated so as to estimate the end to end performance of the processing chain. Finally, the radiometric and geometric performances obtained by the prototype will be presented. In particular, the geo-location performance of the level-1C products which widely fulfils the image quality requirements will be provided.

Applying uncertainties to ocean colour data

Retrieval of operational optical products from the future Global Monitoring for Environment and Security (GMES) Sentinel-3 mission aims to provide continuity of existing missions delivering ocean/land colour, surface temperature and sea surface topography data. This paper describes the current status of the Sentinel-3 Level 2 Optical Prototype Processor (O-L2PP) whose development includes not only a list of products, but also associated uncertainty estimates—a key requirement for the processor. Examples of the approaches adopted within the Ocean and Land Colour Instrument (OLCI) processing module demonstrate how uncertainties can be estimated.