Radar Imagery
Functioning of the radar
A weather RADAR (Radio Detection And Ranging) is a wonderful instrument that pinpoints the location where precipitation occurs and gives an estimate of its intensity. A fast rotating antenna emits 600 to 1200 pulses per second. These pulses encounter waterdrops and are reflected back to the emitting antenna. Bigger drops in a large quantity will reflect at a higher intensity than small drops in small quantities. The different intensities are visualised on the radar image by different colours. Areas with a high reflectivity (red colour) help the airspace users to localise dangerous phenomena like thunderstorms, hail and microbursts.Weather radar images on the website
- RADAR Image R-125km : This radar image is updated every 10 minutes and shows the user the locations where rainfall is a possibility within a range of 125km around the radar in Brussels. The echoes on the image depict an estimation of the maximum amount of rainfall (mm/hr). One has to take into account the fact that the shown amount of rainfall does not necessarily correspond with the actual amount of rainfall on surface level. The cross-sections to the top and the right side of the radar image give an indication about the vertical spread (between 1km and 20km) of the maximum observed rainfall in, respectively, a West-East and a North-South
- RADAR Image R-245km : This radar image is updated every 5 minutes and shows the user the locations where rainfall is a possibility within a range of 245 km around the radar in Brussels. The echoes on the image depict precipitation zones as a result of a scan through the atmosphere under an elevation angle of 0.5° (an oblique cut through the atmosphere). The echoes are reflectivity values (dBZ):
- values lower than 20 dBZ are light rain;
- values between 20 and 35 dBZ are moderate rain;
- values above 35 dBZ are heavy rain or thunderstorms.
