The ceilometer CL51 employs a pulsed diode laser LIDAR technology, where short, powerful laser pulses are sent out in a vertical or near-vertical direction. The reflection of light (backscatter) caused by clouds, precipitation or other obscuration is analysed and used to determine the cloud base height, the cloud layer height and the amount of clouds (in octas) in different layers.

UNDER EMBARGO - This dataset contains seasonal physiological measurements from controlled laboratory experiments on two dominant suspension-feeding species expected to colonise floating offshore structures: the blue mussel (Mytilus edulis; AphiaID 140480) and the wrinkled barnacle (Balanus crenatus; AphiaID 106215). The measured parameters include clearance rates, respiration rates, faecal pellet production rates, and faecal pellet sinking velocities. Mussels were collected from an aquaculture longline at the Westdiep SeaFarm, while barnacles were manually retrieved from the intertidal beachhead at Raversijde (Oostende, Belgium). All experiments were conducted using natural seawater collected from offshore sites in the Belgian part of the North Sea. Measurements were repeated across multiple seasons to capture temporal variability in physiological performance. The dataset was produced within the SWiM and EcoMPV projects and is suitable for reuse in ecosystem and biogeochemical modelling, including simulations of phytoplankton dynamics associated with large-scale offshore marine photovoltaic (MPV) developments.

The number of inhabitants on January 1 according to the official definition of the population, by administrative entity (region, province, district and municipality) for Wallonia.

Owners' origin - Real estate companies corresponds to the dataset describing the origin of the legal persons engaged in real estate activities (section L of the NACE-BEL 2008 nomenclature) that are holders of real rights over immovable properties located in Belgium according to the municipality of their headquarters for legal persons settled in Belgium and according to the country or territory of their headquarters for foreign legal persons. This dataset is made up of seven classes. The first class shows, at national level, for each type of property, the total number of parcels, the number of parcels held by holders from each Belgian municipality and the number of parcels held by holders from each country or territory. The number of parcels takes into account the shares actually held. The second class shows this information at the level of the three regions. The following classes do the same at the level of provinces, arrondissements, municipalities, land register divisions and statistical sectors. The dataset is freely downloadable, in the form of zipped CSV files.

Summer and winter maximum daily precipitation given in mm/day that occur once in a year and once in 5, 10, 15 and 30 years (i.e. return periods of 1 year and 5, 10, 15, 30 years). The precipitation extremes are available for the future target year 2085, which corresponds to the middle of the 30-year period 2071-2100, and for mean and high impact scenarios corresponding respectively to the 50th and 95th percentiles of the change factors.

Hail products are derived from the observed vertical profiles of radar reflectivity and the NWP vertical profiles of temperature. Three types of products are generated. poh : probability of hail of any size (larger than 0.5 cm diameter)expressed in %. posh : probability of severe hail(larger than 2cm)expressed in %. mesh : maximum expected size of hailexpressed in mm of hailstone diameter. All products are generated every 5 minutes. This product is not publically available yet.

Annual and seasonal precipitation indices given in number of days: 1/ Wet days: Number of days with precipitation > 0.1 mm/day for winter, autumn, spring, summer; 2/ Dry days: Number of days with precipitation < 0.1 mm/day for winter, autumn, spring, summer; 3/ Average length of dry spells: Mean duration of minimum three consecutive days with precipitation < 0.1 mm/day; 4/ Maximum length of dry spells: Longest period of minimum three consecutive days with precipitation < 0.1 mm/day, occurring once in 20 years. The precipitation indices are available for the present target year 1975, which corresponds to the middle of the 30-year period 1961-1990.

The data set contains a seamless polygonal layer representing the land cover in Belgium for the year 2006 and the year 2012. The polygons are spread over 32 classes from the CORINE Land Cover legend which are present un Belgium. The minimum map unit is 25 ha. The conceptual scale is 1:100 000. The data set also contains a polygon layer showing changes of more than 5 ha in the land cover between 2006 and 2012.

The composite is produced every 5 minutes using the reflectivity data from the Wideumont and Jabbeke weather radars. This product is not publicly available yet.

The national wastewater-based epidemiological surveillance of respiratory syncytial virus (RSV) monitors the RSV presence in several wastewater treatment plants across Belgium. This dataset contains the results per treatment plant since the beginning of the surveillance in January 2024. The results consist of the RSV concentrations over time as well as other data needed for the interpretations such as the flow rates of the treatment plants and the population covered.