The Radiosonde Station of the Department of Meteorology is located in Athalassa. The station became operational in 1981 with the aim to provide upper air measurements, also known as soundings or radio-soundings. These measurements, or soundings, make use of special equipment known as sondes or radiosondes: these devices are equipped with meteorological sensors for measuring atmospheric temperature, humidity, pressure as well as a GPS sensor.
The sonde is attached to a large balloon that is filled with hydrogen or helium gas and is subsequently released. The low relative density of these gases cause the balloon to ascend at a rate of approximately 6 meters per second. Every second during the ascend, the sensors record the values of atmospheric temperature, humidity and pressure, as well as the exact location coordinates of the sonde. The latter can be used to determine the wind speed and direction every second during the ascend. The data are relayed to a ground-based receiver located at the station premises, in real time. As the atmospheric pressure decreases with height, the balloon expands and eventually bursts. This occurs at a height of approximately 20-30 kilometers.
The end result of the sounding is the determination of a thermodynamic profile of the atmosphere, which includes all of the above parameters as a function of height (and time of ascent), from the surface all the way to the stratosphere. This profile is vital for the study of weather systems and for forecasting their behavior on a time scale of hours or a few days ahead, hence as soon as the sounding is complete, the profile is disseminated to the local weather forecasting center as well as to global meteorological information and data centers for further processing and exploitation. Similar sounding stations exist in almost all countries around the globe and their measurements provide a valuable source of information for numerical weather prediction models. Soundings at Athalassa take place twice per day, at 06 and 12 UTC.