What is Sudden Stratospheric Warming?
Sudden stratospheric warming refers to a significant warming at a height of 10 to 50 km in the atmosphere. Various cold waves in Central Europe in recent years have been associat with a sudden warming of this layer.
How does sudden stratospheric warming occur?
During the polar night in the winter months, the so-call polar vortex forms in the stratosphere above the North Pole. This refers to strong westerly winds that circulate around the extremely cold air high above the Arctic. The stronger the winds, the more the air inside the vortex is isolat from the warmer latitudes and the colder it is (left side in the graphic below). In some years, the winds of the vortex can weaken or even reverse. The cold air then sinks quickly in the polar vortex, which can lead to a rapid increase in temperature (up to 50 degrees in a few days) in the stratosphere. When the cold air from the stratosphere spreads into the saudi arabia phone number library troposphere below, it can influence the shape of the polar jet stream (right side in the graphic below).
The graphic shows two views of the earth. The left graphic shows a stable polar vortex. The cold air over the Arctic remains trapp in the vortex. The polar front jet stream is shift northwards. The right graphic shows a weaken polar vortex. The polar front jet stream is wavy and cold air can extend far to the south.
The left graphic shows a stable polar vortex
The cold air over the Arctic remains trapp in the vortex. The polar front jet stream is shift northwards. The right graphic shows a weaken polar vortex. The polar front jet stream is wavy and cold air can extend far to the south. (NOAA)
How can these sudden stratospheric warmings affect our weather?
The sudden warming of the stratosphere can weaken the polar creating and managing sales funnels front jet stream and cause it to lurch, meaning it tends to form waves and thus encourage the formation of large awb directory blocking high pressure areas. These tend to form over the North Atlantic and Scandinavia. In these cases, Switzerland is locat on the southern ge of the inflow of arctic polar air, which causes cold winter weather here.
Photo with snow-cover mountains. In the middle of the picture is the Stoos ski area. In the background you can see the Uri Rotstock mountain.
The little snow that is still lying around at the moment could last for a long time if there is a significant cold snap in the coming weeks. Photo taken today from the Ibergeregg looking towards Stoos. (Photo: D. Gerstgrasser.
