The Environment Agency has updated the process for releasing radiosondes at the aerological station at Tallinn-Harku to a completely automated system. This will allow for more frequent data transmission, analysis and thus also more accurate weather forecasts.
Automatic sonde stations are in widespread use in the world, with similar stations in use in Finland, Sweden and Norway, for example. But only Estonia has the latest system, said Taimar Ala, director general of the Environment Agency.
"While it used to take an observer up to two hours to prepare, calibrate, fill with helium and release a radiosonde, the entire process is now done by a modern automated system, which takes just half an hour," Ala said, noting the savings in both time and manpower.
Sounding by the instrument takes approximately an hour and a half, during which time a radiosonde sent into the sky via balloon continuously transmits data to the ground. While the sounding process used to conclude the moment the balloon broke due to air pressure and began to plummet back toward earth, newer radiosondes continue to transmit data to meteorologists on their descent as well.
"The old sonde sent us data every 30 seconds, but the new one [transmits data] every two seconds," explained Miina Krabbi, director of the Environment Agency's Meteorological Observation Department. "The radiosonde transmits data to us regarding changes in air temperature in various layers of air, how the humidity changes, and wind direction and speed."
Under favorable conditions, such radiosondes can reach altitudes of up to 30 kilometers. Depending on wind conditions, they may also be carried several hundred miles away; Finnish radiosondes have been found on Estonian shores, for example, and vice versa.
Data collected by the radiosondes is sent to both the Environment Agency's Weather Forecasting Department as well as an international database. As the density of the sondes' data communication has increased, this will allow for more accurate forecasts for both civilian and aviation forecasts.
Radiosondes have been in use in Estonia since 1953. They are released once per day, at 11:30 p.m. UTC.
Editor: Aili Vahtla