As a constellation of two polar-orbiting satellites they carry a 12 m-long advanced synthetic aperture radar (SAR), working in C-band. The Sentinel-1 constellation provides high reliability, improved revisit time, geographical coverage and rapid data dissemination to support operational applications in the priority areas of marine monitoring, land monitoring and emergency services. The advantage of radar as a remote sensing tool is that it can continuously image Earth’s surface through rain and cloud, and regardless of whether it is day or night. This is particularly useful for monitoring areas prone to long periods of darkness – such as the Arctic – or providing imagery for emergency response during extreme weather conditions.
Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The combination of high resolution, novel spectral capabilities, a swath width of 290 km and frequent revisit times provides unprecedented views of Earth.
Level-1 Single Look Complex (SLC) products consist of focused SAR data, geo-referenced using orbit and attitude data from the satellite, and provided in slant-range geometry. Slant range is the natural radar range observation coordinate, defined as the line-of-sight from the radar to each reflecting object. The products are in zero-Doppler orientation where each row of pixels represents points along a line perpendicular to the sub-satellite track. Read more
Level-1 Ground Range Detected (GRD) products consist of focused SAR data that has been detected, multi-looked and projected to ground range using the Earth ellipsoid model WGS84. The ellipsoid projection of the GRD products is corrected using the terrain height specified in the product general annotation. The terrain height used varies in azimuth but is constant in range (but can be different for each IW/EW sub-swath). Read more
The Leaf Area Index is defined as half the total area of green elements of the canopy per unit horizontal ghoeken area. The satellite-derived value corresponds to the total green LAI of all the canopy layers, including the understory which may represent a very significant contribution, particularly for forests. Practically, the LAI quantifies the thickness of the vegetation cover. Read more
The Fraction of Absorbed Photosynthetically Active Radiation quantifies the fraction of the solar radiation absorbed by live leaves for the photosynthesis activity. Then, it refers only to the green and alive elements of the canopy. The FAPAR depends on the canopy structure, vegetation element optical properties, atmospheric conditions, and angular configuration. To overcome this latter dependency, a daily integrated FAPAR value is assessed. Read more
The Fraction of Vegetation Cover corresponds to the fraction of ground covered by green vegetation. Practically, it quantifies the spatial extent of the vegetation. Because it is independent from the illumination direction and it is sensitive to the vegetation amount, fCover is a very good candidate for the replacement of classical vegetation indices for the monitoring of ecosystems. Read more
The Normalized Difference Vegetation Index is a simple and effective vegetation index to quantify the vegetation amount. It is an indicator of the greenness of the biomes, little scale dependant and is closely linked to the FAPAR. Read more
Currently certain Web Services are available which can be used for Sentinel-2 data viewing, discovery and access. More information on the Sentinel Web Services are on-line available
- OGC WMTS: It is possible to access the WMTS directly by using a simple web browser or desktop tools such as QGIS.
- OGC WMS: The Web Map Service (WMS) is a standard protocol for serving pre-rendered georeferenced map images over the internet. VITO applies to the OGC WMTS Implementation Standard (OGC 06-042). It is possible to access the WMS directly by using a simple web browser or desktop tools such as QGIS.
- OGC WCS: The OGC Web Coverage Service (WCS) standard defines Web-based retrieval of coverages – that is, digital geospatial information representing space/time-varying phenomena.