What is Sudden Stratospheric Warming?
The Southern India received excessively heavy rainfall (ten times the normal) between January 1, 2021 and January 17, 2021. This winter rain, according to the scientists, is due to sudden stratospheric warming that occurred in Arctic region.
Sudden Stratospheric Warming
- The Sudden Stratospheric Warming is an event where the polar stratospheric temperature increases up to fifty degrees Celsius. It is preceded by a situation where the polar jet stream of westerly winds in the northern hemisphere is disturbed by natural weather patterns. This is usually addressed as polar vortex.
- The polar vortex is a whirling cone of low pressure over the poles. The polar vortex is the strongest in winter. It spins in the stratosphere.
- During winter, the polar vortex is the strongest due to the difference in temperature between polar and mid latitude regions.
- When the polar vortex is the strongest, it forms a wall protecting the mid-latitudes from cold Arctic air. When Polar Vortex weakens, the stratosphere begins to warm and the event is called Sudden Stratospheric Warming.
2021 Sudden Stratospheric Warming
The Sudden Stratospheric Warming occurred on January 5, 2021 according to weather forecast models. The Stratosphere is the layer of the atmosphere at a height of ten to fifty kilo metres above the earth surface. During Sudden Stratospheric Warming, the polar stratospheric temperature might increase up to fifty degree Celsius. Around forty Sudden Stratospheric Warming events have occurred in the last sixty years.
2019 Sudden Stratospheric Warming
Very rarely the SSW also occurs in South Pole. The last SSW in south pole occurred in 2019. During the 2019 SSW, the north pole vortex split into three smaller vortices. This released cold winds into the southern regions below it. Lake Michigan was frozen in Chicago due to this weather condition.
2018 Sudden Stratospheric Warming: Beast from the East
The 2018 Sudden Stratospheric Warming was referred to “Beast from the East” as it brought in unusually cold weather conditions in UK and also in several other parts of the world.
Usually, the Beast from the East term is used to describe cold conditions in the UK. The condition occurs due to the Easterly winds that flows from Siberia towards the UK.