Sentinel-1 is a constellation of two imaging radar satellites operated by ESA. Sentinel-1B experienced an anomaly which rendered it unable to deliver radar data in December 2021, and the launch of Sentinel-1C is planned for 2023.

EnviSat was a satellite mission monitoring Earth's environment. EnviSat application areas included meteorology, climatology, environment, atmospheric chemistry, vegetation, hydrology, land use, and ocean and ice processes. EnviSat was a research mission that carried ten instruments and provided a wealth of data related to Earth's health and climate change. EnviSat carried the Medium Resolution Imaging Spectrometer( MERIS), Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), Radar Altimeter-2 (RA-2), Laser Retro-Reflector (LRR), Microwave Radiometer (MWR), Advanced SAR (ASAR), Global Ozone Monitoring by Occultation of Stars (GOMOS), Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY), Advanced Along Track Scanning Radiometer, provided by the UK and Australia (AATSR), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS).

The Arctic Oscillation (AO) is the dominant pattern of non-seasonal sea-level pressure (SLP) variations north of 20N, and it is characterized by SLP anomalies of one sign in the Arctic and anomalies of opposite sign centered about 37-45N. Additional information is available for the Arctic Oscillation (AO) and for the North Atlantic Oscillation (NAO), a close relative of the AO (http://jisao.washington.edu/ao/)

The Arctic is warming more than twice as fast as the global average, making climate changess polar effects more intense than anywhere else in the world. The Arctic accounts for half of the organic carbon stored in soils. There is high confidence that the thaw of terrestrial permafrost will lead to carbon release, but only low confidence regarding timing, magnitude and relative role of CO2 versus CH4 according to the sixth assessment report of IPCC (2021). There is general consensus that these issues can be tackled through support by satellite observations, but this has not been fully exploited to date. The recently inaugurated Arctic Methane and Permafrost Challenge (AMPAC) strives to address these questions inter alia through making use of synergistic measurements, activities to improve satellite retrievals with a clear focus on high latitudes, and promoting new dedicated satellite sensors as well as improving validation of existing and upcoming satellite missions.

The Share of Built-Up Change (SBUC) 2018-2021 layer is part of the High Resolution Layer (HRL) Imperviousness and contains the change of built-up per pixel (increase or decrease in percentage) as derived from the difference between the Impervious Built-Up (IBU) status layers for the reference years 2018 and 2021, in an aggregated version of 100m spatial resolution. The production of the HRL Imperviousness is coordinated by EEA in the frame of Copernicus, the Earth observation component of the European Union’s Space programme. The product is a raster dataset with 100-meter grid spacing (spatial resolution) that covers the 38 Eionet member and cooperating countries as well as the United Kingdom (i.e. EEA38+UK). It is distributed as 100 x 100 km tiles that are fully conformant with the EEA reference grid.

The "EMODnet Digital Bathymetry (DTM)- 2024" is a multilayer bathymetric product for Europe’s sea basins covering: • the Greater North Sea, including the Kattegat and stretches of water such as Fair Isle, Cromarty, Forth, Forties,Dover, Wight, and Portland • the English Channel and Celtic Seas • Western Mediterranean, the Ionian Sea and the Central Mediterranean Sea • Iberian Coast and Bay of Biscay (Atlantic Ocean) • Adriatic Sea (Mediterranean) • Aegean - Levantine Sea (Mediterranean). • Madeira and Azores (Macaronesia) • Baltic Sea • Black Sea • Norwegian and Icelandic Seas • Canary Islands (Macaronesia) • Arctic region and Barentz Sea The DTM is based upon 22032 bathymetric survey data sets and Composite DTMs that have been gathered from 66 data providers from 28 countries riparian to European seas and beyond. Also Satellite Derived Bathymetry data products have been included fro Landsat 8 and Sentinel satellite images. Areas not covered by observations are completed by integrating GEBCO 2024 and IBCAO V4. The source reference layer in the portal viewing service gives metadata of the data sets used with their data providers; the metadata also acknowledges the data originators. The incorporated survey data sets itself can be discovered and requested for access through the Common Data Index (CDI) data discovery and access service that contains > 41.000survey data sets from European data providers for global waters. The Composite DTMs can be discovered through the Sextant Catalogue service. Both discovery services make use of SeaDataNet standards and services and have been integrated in the EMODnet portal (https://emodnet.ec.europa.eu/en/bathymetry#bathymetry-services ). In addition, the EMODnet Map Viewer (https://emodnet.ec.europa.eu/geoviewer/ ) gives users wide functionality for viewing and downloading the EMODnet digital bathymetry such as: • water depth (refering to the Lowest Astronomical Tide Datum - LAT) in gridded form on a DTM grid of 1/16 * 1/16 arc minute of longitude and latitude (ca 115 * 115 meters). • option to view depth parameters of individual DTM cells and references to source data • option to download DTM in 59 tiles in different formats: ESRI ASCII, XYZ, EMODnet CSV, NetCDF, GeoTiff and SD • option to visualize the DTM in 3D in the browser without plug-in • layer with a number of high resolution DTMs for coastal regions • layer with wrecks from the UKHO Wrecks database. The EMODnet DTM is also available by means of OGC web services (WMS, WFS, WCS, WMTS), which are specified at the EMODnet Bathymetry portal. The original datasets themselves are not distributed but described in the metadata services, giving clear information about the background survey data used for the DTM, their access restrictions, originators and distributors and facilitating requests by users to originator.

The high resolution forest product consists of three types of (status) products and additional change products. The status products are available for the 2012, 2015 and 2018 reference years: 1. Tree cover density providing level of tree cover density in a range from 0-100%; 2. Dominant leaf type providing information on the dominant leaf type: broadleaved or coniferous; 3. A Forest type product. The forest type product allows to get as close as possible to the FAO forest definition. In its original (20m) resolution it consists of two products: 1) a dominant leaf type product that has a MMU of 0.5 ha, as well as a 10% tree cover density threshold applied, and 2) a support layer that maps, based on the dominant leaf type product, trees under agricultural use and in urban context (derived from CLC and high resolution imperviousness 2009 data). For the final 100m product trees under agricultural use and urban context from the support layer are removed. The high resolution forest change products comprise a simple tree cover density change product for 2012-2015 (% increase or decrease of real tree cover density changes). The production of the high resolution forest layers was coordinated by the European Environment Agency (EEA) in the frame of the EU Copernicus programme.

ClONO2 - This is a stratospheric reservoir species for chlorine and nitrogen, two of the catalysts in the breakdown of ozone. It reacts with HCl at low temperatures on the surfaces of polar stratospheric clouds (PSCs over Antarctica and possibly in the stratosphere over the Arctic). That normally slow reaction heterogeneously produces molecular chlorine and nitric acid. The former outgases from the PSC surface and is quickly photolyzed by 450 nm or shorter wavelength light to form chlorine radicals which rapidly catalyze the breakdown of ozone (see chlorine monoxide). [Science; v 238; pages 1258-1260; 1987.] [Science; v 258; pages 1342-1345; 1992.]

The High Resolution Layer (HRL) Grassland Change 2015-2018 raster product at 20m resolution provides information on changes in grassland vegetation cover between the reference years 2015 and 2018. The thematic classes indicate all non-grassland areas, grassland gain and grassland loss, unchanged grassland in both years and unverified grassland gain and loss areas for the pan-European area of EEA38 and the United Kingdom. The production of the High Resolution grassland layers was coordinated by the European Environment Agency (EEA) in the frame of the EU Copernicus programme. This dataset is provided as 20 meter rasters in 100 x 100 km tiles grouped according to the EEA38 countries and the United Kingdom (fully conformant with the EEA reference grid). The HRL Grassland layer is the main High Resolution grassland product. This grassy and non-woody vegetation baseline product includes all kinds of grasslands: managed grassland, semi-natural grassland and natural grassy vegetation. It is a binary status layer for the 2015 reference year mapping grassland and all non-grassland areas in 20m and (aggregated) 100m pixel size and, for the 2018 reference year, in 10m and (aggregated) 100m pixel size.

The High Resolution Layer Imperviousness Change (IMC) 2015-2018 is a 20m raster dataset showing change in imperviousness between 2015 and 2018 reference years, produced in the frame of the EU Copernicus programme. The high resolution imperviousness products capture the percentage and change of soil sealing. Built-up areas are characterized by the substitution of the original (semi-) natural land cover or water surface with an artificial, often impervious cover. These artificial surfaces are usually maintained over long periods of time. A series of high resolution imperviousness datasets (for the 2006, 2009, 2012, 2015 and 2018 reference years) with all artificially sealed areas was produced using automatic derivation based on calibrated Normalized Difference Vegetation Index (NDVI). This series of imperviousness layers constitutes the main status layers. They are per-pixel estimates of impermeable cover of soil (soil sealing) and are mapped as the degree of imperviousness (0-100%). Imperviousness change layers were produced as a difference between the reference years (2006-2009, 2009-2012, 2012-2015, 2015-2018 and additionally 2006-2012, to fully match the CORINE Land Cover production cycle) and are presented 1) as degree of imperviousness change (-100% -- +100%), in 20m and 100m pixel size, and 2) a classified (categorical) 20m change product. This dataset is provided as 20 meter rasters (fully conformant with EEA reference grid) in 100 x 100 km tiles grouped according to the EEA38 countries and the United Kingdom.