Since August 2019, users of the RMI smartphone app are able to send an observation of the meteorological conditions at a certain place and a certain time. The observations provide information about the weather conditions and potentially severe weather to the other users and to RMI. The collection of citizen weather reports is a valuable complement to the information obtained with the classical instruments like stations, radar and satellite. The data can be exploited for nowcasting, warnings and model verification, and eventually in assimilation. A general introduction of the data and their characteristics can be found in Reyniers et al. (2023). A basic quality control is implemented on the received observations via a plausibility check. This plausibility check determines whether an observation is plausible, suspicious or false, by comparing it to the INCA-BE nowcasting system using a simple thresholding scheme. INCA-BE is RMI's operational nowcasting system described in Reyniers et al. (2021). There is no strict spatial extent since there is no restriction at the input side: users can send observations from all over the globe. The bulk of the observations are received from within Belgium. Note that the plausibility check is not available for reports from outside Belgium.

From multiple observations during the day with UV spectrophotometers a daily value of the ozone column is calculated. This product is not publically available yet.

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.

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.

Gridded observational data provides an estimate of the spatial distribution of a meteorological variable based on observations. While instrumental measurements are taken at irregularly distributed stations, gridded data represents the meteorological variable on a predefined regular grid. Gridded observational data is of strong benefit in disciplines applying distributed quantitative models to examine the influence of weather and climate. Gridded data are also very convenient to provide estimations for any specific location of interest for the user. Gridded observational data covering Belgium at a spatial resolution of 5 km (= 1360 pixels) are available for several variables (precipitations, air temperature, sunshine duration, solar radiation, relative humidity and wind speed) as well as different temporal resolutions (daily, monthly, seasonal, annual values as well as long-term climate averages). The gridded database starts in 1961 for most variables and is updated each day with the available observations of the previous day. All grids are then updated for archiving as soon as the data quality control is completed. In addition to the 5km x 5km grids, spatial averages for all each Belgian municipality are also available. This product is not publically available yet. The daily gridded climate data are available for academic profiles after registration on our open data website.

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.

This dataset comprises historical orthophotos from the 2000s to 2009, derived from aerial surveys carried out by the National Geographic Institute (NGI). The ground sample distance (GSD) of the images ranges from 25 to 100 cm. The mosaics were created using aerial photography campaigns dating from 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 and 2009. The original photographs were digitised and orthorectified in the Lambert 2008 coordinate system. The spatial coverage for each year corresponds to the areas for which photographs were available. High-resolution data can be ordered via https://shop.ngi.be/fr/photos-aeriennes/

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.

Polar volume reflectivity data from the Jabbeke weather radar. Volume data files are produced every 5 minutes from a multiple elevation scan. This product is not publicly available yet.

The files contain the population characteristics (total, gender and/or age groups) by 1 km² square grid cell in Belgium on January 1st, according to the European definition of the population. The European definition takes into account the 12-months criterion and includes asylum seekers. More information at https://ec.europa.eu/eurostat/cache/metadata/en/demo_pop_esms.htm#unit_measure1589188532500.