A characteristic feature of high pressure weather conditions in the winter months is a reversal! of the classic temperature decrease with altitude! Normally, in the weather layer of the atmosphere! the so-called troposphere, the temperature decreases with altitude! in dry conditions by exactly 0.98 °C per 100 meters. This temperature curve is often reversed in stable winter high pressure weather. Sinking processes in the middle troposphere cause a sometimes significant warming in the mountains! near the ground the disconnected air! layer cools down more and more as! a result of the negative radiation balance and lack! of fresh air supply, and a cold air lake forms. Cold below and warm above thus reverses the classic vertical temperature distribution! forming a temperature inversion.
According to radiosonde ascents over Payerne
he Swiss Plateau was under a significant temperature inversion! on Wednesday night. The temperature (red) in the lower! layers of the atmosphere initially increases with altitude (from around -1 to almost +10 °C) and only then decreases.
According to radiosonde ascents over Payerne, the Swiss Plateau was under a significant temperature inversion on Wednesday night. The temperature (red) in the lower layers of the atmosphere initially increases with altitude (from around -1 to almost +10 °C) and only then decreases.
barrier layer at 600-700 meters
On Wednesday, the temperature inversion was at a height of around 600 to 700 meters. The height of the inversion is often visible with the upper limit of fog or high fog over the lowlands. The fog mostly cleared up by early afternoon on Wednesday, but in northeastern Switzerland it lingered longer, as it did on Tuesday.
>The (flat) sea of fog on Wednesday morning, seen from the Meteosat senegal phone number library satellite at an altitude of 36,000 km. Low clouds and fog are shown in this channel in white to light turquoise.
The (flat) sea of fog on Wednesday morning, seen from the Meteosat satellite at an altitude of 36,000 km. Low clouds and fog are shown in this channel in white to light turquoise.
The fog ceiling was also visible from
the Hirzelhöchi at around 600 metres, here with a view towards Central Switzerland and the Bernese Oberland. Photo: D. Gerstgrasser
The fog ceiling was also visible from the Hirzelhöchi at around 600 metres, here with a view towards Central Switzerland and the Bernese Oberland. Photo: D. Gerstgrasser
At the edge of the fog in St. Gallen at about 600 to 650 meters. Image: Meteomeldungen/App.
>At the edge of the fog in St. Gallen at about 600 to 650 you can see available communication channels with the client meters. Image: Meteomeldungen/App.
>Below the inversion, the temperature increases with altitude, awb directory the air mass is stably layered and vertical movements in the air are prevented. If there is no horizontal transport of air masses (advection), the cold air layer close to the ground ages and becomes enriched with suspended particles (aerosols). This can be seen in the lowlands both in the haze that remains and in the pollutant concentration of fine dust PM10 and nitrogen dioxide, which has increased in recent days but has not exceeded daily limit values.
Course of the fine dust concentration (PM10) between January 15 and February 15, 2023 at the Aarau-Buchenhof measuring site. Source: www.luftqualitaet.ch
Course of the fine dust concentration (PM10) between January 15 and February 15, 2023 at the Aarau-Buchenhof measuring site. Source: www.luftqualitaet.ch
air mass exchange
While the air quality has deteriorated in the Central Plateau, the warm and very dry air further up ensures the best mountain weather.
