RMI operates a network of 17 automatic weather stations in Belgium. These weather stations report meteorological paramaters such as air pressure, temperature, relative humidity, precipitation (quantity, duration), wind (speed, gust, direction), sunshine duration, shortwave solar radiation and infrared radiation every 10 minutes. Daily AWS data are computed from the 10-min observations.

Regional Climate Model: ALARO-0 model This data includes spatially-detailed climate projections for Belgium and can be used for climate-change impact assessments (historical and RCP simulations) and analysis of past climate (evaluation simulation). Note that the historical run will, by construction, not correspond to past observations. For further details please contact RMI or cordex@meteo.be. This dataset has been obtained by dynamical downscaling using the regional climate model ALARO-0 (Termonia et al., 2018a) in the context of the BELSPO-funded project CORDEX.be (Termonia et al, 2018b, www.euro-cordex.be). The downscaling methodology is in line with the guidelines of the Coordinated Regional Downscaling Experiment (CORDEX; Jacob et al. 2014) and follows the climate scenario's RCP2.6, RCP4.5 and RCP8.5 as suggested by the Intergovernmental Panel on Climate Change. The spatial resolution of the data is 4-km and the domain covers a region centered over Belgium. The temporal resolution of the data is daily over long continuous periods. The historical experiment covers the period 1976-2005 and the RCP scenarios cover the period 2007-2100. Precipitation data has undergone thorough validation (Van de Vyver et al., 2021) and investigation (Helsen et al., 2020). The 4-km simulations were performed in a double (one-way) nesting setup where the Belgian domain was nested in an ALARO-0 run over the EURO-CORDEX domain (Berckmans et al, 2021) with a resolution of 0.44° (≃ 50 km) and validated in Giot et al. (2016). Around Europe the latter was forced by the global climate model CNRM-CM5 (historical, RCP 2.6, RCP 4.5, RCP 8.5) that has a resolution of about 1.4° (≃ 155 km) and is part of the Coupled Model Intercomparison Project CMIP5. Giot et al., 2016. DOI: 10.5194/gmd-9-1143-2016 Helsen et al., 2020. DOI: 10.1007/s00382-019-05056-w Termonia et al., 2018a. DOI: 10.1016/j.cliser.2018.05.001 Termonia et al., 2018b. DOI: 10.5194/gmd-11-257-2018 Jacob et al., 2014. DOI: 10.1007/s10113-013-0499-2 Van de Vyver et al., 2021. DOI: 10.1175/JAMC-D-21-0004.1 Further info can be found on https://cordex.org/experiment-guidelines/ http://www.belspo.be/belspo/brain-be/projects/FinalReports/CORDEXbe_FinRep_AD.pdf Periods: * present climate: HIST_1975_2005 * future climate, 3 emission scenarios RCP 2.6, RCP 4.5, RCP 8.5: RCP26_2007_2100, RCP45_2007_2100, RCP85_2007_2100 Variables: 1. et0 = Reference Evapotranspiration [kg m-2 s-1]; to get this in mm/day, the data should be multiplied by 60*60*24 = 86400. It is calculated following the FAO method (Allen et al., 1998) using the Penman-Monteith equation for reference (potential) crop evapotranspiration 2. hurs = relative humidity [%] 3. pr = precipitation [kg m-2 s-1]; to get precipitation in mm/day, the data should be multiplied by 60*60*24 = 86400 4. rsds = global solar radiation [W m-2] 5. sfcWind = wind at 10 m [m s-1] 6. tas = near-surface (2 m) air temperature at 2 m [K] 7. tasmax = daily maximum near-surface (2 m) air temperature [K] 8. tasmin = daily minimum near-surface (2 m) air temperature [K] 9. et0 = Reference Evapotranspiration [kg m-2 s-1]; to get this in mm/day, the data should be multiplied by 60*60*24 = 86400

Daily forecasts for each belgian commune, from current day up to the next 7 days. This product is not publically available.

Hourly forecasts for each belgian commune, from current hour up to the next 5 days. This product is not publically available.

Bird density profiles are derived from weather radar volume data in real time, by the vol2bird algorithm as described in Dokter et al. (2011, 2019). The vol2bird algorithm exploits the radar reflectivity characteristics of different scatterers in the atmosphere, in order to distinguish biological from non-biological radar echoes. Once biological scatterers are isolated in the volume files, the reflectivity of these scatterers is converted in an estimate of the bird density per vertical layer of 200m, using a mean cross section of 11 cm2. The vbird profiles are provided for the following radars, with the radar owner in parentheses: Jabbeke (RMI), Wideumont (RMI), Helchteren (VMM), Zaventem (Skeyes), Herwijnen (KNMI), Den Helder (KNMI), Neuheilenbach (DWD), Essen (DWD), Abbeville (Météo-France) and Avesnois (Météo-France). References: - Dokter A.M., Liechti F., Stark H., Delobbe L., Tabary P., Holleman I., Bird migration flight altitudes studied by a network of operational weather radars, J. R. Soc. Interface, 8, 30–43, 2011, DOI 10.1098/rsif.2010.0116 - Dokter A.M., Desmet P., Spaaks J.H., van Hoey S., Veen L., Verlinden L., Nilsson C., Haase G., Leijnse H., Farnsworth A., Bouten W., Shamoun-Baranes J., bioRad: biological analysis and visualization of weather radar data, Ecography, 42, 852-860, 2019, DOI 10.1111/ecog.04028

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.

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.

The SYNOP data of RMI contain the observations of the synoptic network, currently consisting of 29 stations, 13 of which are owned by RMI. The other stations belong to MeteoWing (8 stations), Skeyes (7 stations). There is also 1 foreign station. All SYNOP data is given in Universal Time! (local time winter = UT +1; local time summer = UT + 2) Parameters: 1. Precipitation: PRECIP_QUANTITY + PRECIP_RANGE 2. Temperature: TEMP + TEMP_MIN + TEMP_MAX + TEMP_GRASS_MIN 3. Wind: WIND_SPEED + WIND_SPEED_UNIT + WIND_DIRECTION + WIND_PEAK_SPEED 4. relative humidity: HUMIDITY_RELATIVE 5. weather type: WEATHER_CURRENT 6. air pressure: PRESSURE of PRESSURE_STATION_LEVEL 7. sunshine duration: SUN_DURATION_24H 8. Global radiation: SHORT_WAVE_FROM_SKY_24HOUR 9. Total cloudiness: CLOUDINESS

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

Weather Model 'Alaro' A numerical forecast model is a computer program that simulates the evolution of the atmosphere. Available parameters : Temperature, Max. temperature, Min. temperature, Dewpoint temperature, Wet-bulb potential temperature, Cloud cover (low, medium, high, tot.), U and V wind component, U, V and vertical velocity, Stationary boundary layer (SBL) Gust, Total precipitation, Large scale rain, Convective rain, Large scale snow, Convective snow, Relative Humidity, Specific humidity, Geopotential, Mean sea level pressure, Orography, freezing level / 0°C isotherm, Convective available potential energy (CAPE)