About the RMI

The weather balloon soundings of the RMI

To measure the amount of ozone in relation to the height, a meteorological balloon is risen 3 times per week in Uccle. On that balloon instruments are fixed that measure, up to 30 to 35 km height, beside the ozone concentration also the course of the temperature, the relative humidity, the wind direction and wind speed. This way a vertical profile of the atmosphere can be generated.

Although these measurements are only snapshots, they provide a wealth of information due to the high vertical resolution (from 100 to 200m). The operational usage in the weather forecast models and the scientific research about the mechanisms that determine the weather benefit from these measurements. Also temperature inversions (temperature increase with height) and the development of thunder storm cells can be derived from that. However, the focus of the RMI of the balloon soundings is on measuring the profile of the ozone concentration. This provides at the same time an image of the ozone on the ground (which can be harmful to health) and the “ozone layer” higher up (which can protect us from the dangerous UV radiation). These ozone measurements are also frequently used as reference measurements of ozone observations by satellites, which have a much lower vertical resolution.

Example of measurement data from a balloon sounding with vertical profile of temperature (red line, in°C), relative Humidity (green line, in %), wind direction (light blue line, in ° North-orientated), wind speed (dark blue line, in m/s) and the ozone concentration (pink line, in mmPa).