Measurement of the ozone profile
Three times a week, MeteoSwiss measures the ozone profile using a radio-sounding balloon. The ozone sonde is based on the chemical reaction between the ozone (O3) and potassium iodide (KI) molecules part of a chemical solution contained in the small white capsules (see figure). The air is pumped into the inside of the Styrofoam sonde housing and then channelled into the capsule, which contains the low concentration potassium iodide solution. According to the principle of an electrochemical cell, the ozone concentration in the air can be measured on the basis of the electrical current between two electrodes. This device is light enough to be elevated using a radio-sounding balloon, allowing for a precise in-situ measurement of the ozone profile from ground level up to an altitude of 30-35 km.