Radiosonde Observations

The foundation of radiosonde devices lies in the development efforts of French scientists Bure and Idrac in the early 1920s and the independent work of Russian scientist Pavel Molchanov. These devices were designed to collect information about atmospheric conditions at various levels and transmit this data to Earth via radio waves. In 1930, Molchanov developed the first radiosonde, widely recognized as the precursor to modern instruments. Within a short time, this system began to be adopted by meteorological offices in many countries.

A radiosonde is an instrument that measures temperature, pressure, humidity, wind direction, and wind speed in the atmosphere. Deployed into the atmosphere attached to a balloon filled with helium or hydrogen gas, these devices transmit real-time data to ground stations via radio waves. Modern radiosondes are equipped with GNSS (Global Navigation Satellite System) technology, and the data collected is used in meteorological analyses, weather forecasting models, and other research.

^{Radiosonde Instrument (Source:} MGM⁾

The radiosonde instrument ascends to altitudes of up to 30–40 kilometers using a balloon. During this ascent, it measures parameters such as temperature, pressure, and humidity at different atmospheric levels. Using GNSS technology, the device’s position data is also obtained, from which wind direction and speed are calculated. The data transmitted by the instrument is received and analyzed by ground stations for use in weather forecasting and other meteorological studies.

The balloon rises at a speed of approximately 360 meters per minute during flight. When it reaches a diameter of about 10 meters, it bursts due to internal pressure, and the instrument descends safely to the ground using a parachute.

^{Radiosonde Balloon}

1. Balloon:
2. 1. Made of latex or neoprene material.
   2. Filled with hydrogen or helium gas.
   3. The size of the balloon varies depending on the target altitude and the weight of the radiosonde instrument.
2. Radiosonde Instrument:
3. 1. Meteorological sensors for measuring temperature, pressure, and humidity.
   2. Electronic data encoder and telemetry transmitter.
   3. GNSS sensors used to determine the instrument’s position.
3. Parachute:
4. 1. Ensures the controlled descent of the instrument after the balloon bursts.
4. Ground Station:
5. 1. Consists of antennas and receiver systems.
   2. Collects, analyzes, and processes data for use in meteorological forecasting models.

^{Radiosonde Balloon (Source:} MGM⁾

Türkiye has nine radiosonde stations. These are:

• Samsun (41°20’ N, 36°15’ E)
• Istanbul (40°54’ N, 29°09’ E)
• Ankara (39°58’ N, 32°51’ E)
• Izmir (38°23’ N, 27°04’ E)
• Isparta (37°47’ N, 30°34’ E)
• Diyarbakır (37°54’ N, 40°12’ E)
• Adana (37°00’ N, 35°20’ E)
• Erzurum (39°54’ N, 41°15’ E)
• Kayseri (38°41’ N, 35°30’ E)

^{Radiosonde Stations (Source:} MGM⁾

These stations were established to monitor air masses affecting Türkiye and to meet national meteorological needs. The World Meteorological Organization (WMO) recommends placing radiosonde stations 250 kilometers apart over land and 1000 kilometers apart over oceans. Turkish stations are positioned in accordance with these criteria and conduct observations twice daily (at 00 UTC and 12 UTC).

Radiosonde observations are used in the following areas:

1. Weather Forecasting and Analysis:
2. 1. Data on pressure, temperature, humidity, and wind at various atmospheric levels are plotted on maps to generate weather forecasts.
   2. Information on height, pressure, temperature, humidity, and wind at standard isobaric levels is plotted on maps for analytical studies.
2. Aviation:
3. 1. Plays a critical role in civil and military flight planning.
3. Air Quality Analysis:
4. 1. Provides data for air pollution forecasting and modeling.
4. Numerical Weather Prediction Models:
5. 1. Form the foundational data for modern meteorological models.

Hydrogen gas is commonly used to inflate radiosonde balloons. Due to hydrogen’s high flammability, safety measures such as gas detection sensors, fire suppression systems, and flame detectors are implemented. Alternatively, helium gas may be used, especially in areas where safety is a critical concern.