What is sudden stratospheric warming? 640x480

videoinmotioneire

12 Jan 201302:23

Summary

TLDRSudden stratospheric warming, a meteorological phenomenon, has been linked to unusually cold and snowy winters in the Northern Hemisphere. This occurs when the polar night jet, a ring of strong westerly winds, weakens and reverses direction due to disturbances from the troposphere. The resulting collapse of cold air leads to rapid warming in the stratosphere, sometimes by 30-40°C in just a few days. While not a definitive indicator, such warming can signal an impending cold snap, with about two out of three events leading to subsequent cold weather conditions.

Takeaways

🌡️ Over the last few years, parts of the Northern Hemisphere have experienced unusually cold and snowy winters.
🌍 One reason for this is a phenomenon called sudden stratospheric warming.
🌀 The troposphere extends from the surface to about 10 kilometers and is where most weather occurs.
☁️ Above the troposphere is the stratosphere, which has thinner, drier air and little to no cloud cover.
🌌 During the polar night, stratospheric temperatures can fall as low as minus 70 or minus 80 degrees Celsius.
💨 Around the cold polar air, there is a ring of strong westerly winds known as the polar night jet.
🌊 Disturbances from the troposphere can cause the polar night jet to wobble and weaken.
⚡ When the jet weakens significantly, cold stratospheric air collapses downward, compresses, and warms rapidly, resulting in sudden stratospheric warming.
📈 This warming can cause stratospheric temperatures to rise by 30 or 40 degrees Celsius in just a few days.
🌬️ These reversed winds can sometimes reach the lower atmosphere, weakening the Jetstream and leading to high pressure systems, or blocking highs, that bring cold surface winds from the Arctic.

Q & A

What is sudden stratospheric warming and why does it affect our winters?
-Sudden stratospheric warming is a meteorological phenomenon where the temperature in the stratosphere increases rapidly, sometimes by 30 to 40 degrees Celsius within a few days. It can affect our winters because when the polar night jet weakens and reverses due to this warming, it can lead to the cold stratospheric air collapsing and warming rapidly, which may influence the weather patterns at lower levels, potentially causing cold snaps and heavy snowfall.
What is the troposphere and how does it relate to our weather?
-The troposphere is the lower level of the Earth's atmosphere, extending from the surface to about 10 kilometers. It is where most of our weather occurs because it contains the majority of the atmosphere's mass and water vapor.
What is the stratosphere and why is it important for sudden stratospheric warming?
-The stratosphere is the atmospheric layer above the troposphere, characterized by thin, dry air and the presence of the ozone layer. It is important for sudden stratospheric warming because this is where the polar night jet forms, and where the temperature can drop significantly, setting the stage for rapid warming events.
What causes the polar night jet to wobble and potentially break?
-The polar night jet can wobble and potentially break due to disturbances coming up from the troposphere. These disturbances can cause the jet to wave more, and when the waves get big enough, they can break, similar to waves on a beach.
How does the weakening of the polar night jet lead to sudden stratospheric warming?
-When the polar night jet weakens and even reverses direction due to the wobbles caused by tropospheric disturbances, it allows the cold stratospheric air to collapse downwards towards the pole. As this air compresses, it warms rapidly, resulting in sudden stratospheric warming.
What is the significance of the graph mentioned in the script?
-The graph in the script illustrates the dramatic temperature changes associated with sudden stratospheric warming. The green line represents the average temperature in the stratosphere, while the red line shows the actual temperature measurements, which can spike significantly, indicating the warming event.
How can reversed easterly winds from the stratosphere impact the lower atmosphere?
-Reversed easterly winds from the stratosphere can work their way down into the lower atmosphere, weakening the Jetstream that normally pushes weather systems from west to east. This can lead to the formation of blocking highs, which can allow cold surface winds to escape from the Arctic, potentially bringing hard frost and heavy snow.
What is a blocking high and how does it relate to sudden stratospheric warming?
-A blocking high is a high-pressure system that can form when the Jetstream is weakened by reversed easterly winds from the stratosphere. It can disrupt the typical west-to-east movement of weather systems, leading to cold surface winds from the Arctic, which may result in cold snaps and heavy snowfall.
Is there a direct correlation between sudden stratospheric warming and cold snaps?
-While sudden stratospheric warming can be a useful sign that a cold snap is on the way, it is not a definitive proof. Only about two out of three warming events actually result in a following cold snap.
How can we predict the effects of sudden stratospheric warming on our weather?
-We can predict the effects of sudden stratospheric warming on our weather by monitoring the temperature changes in the stratosphere and observing the behavior of the polar night jet. However, it's important to note that not every warming event will lead to a cold snap, so additional meteorological data and models are needed for accurate predictions.
What is the role of the ozone layer in the stratosphere during sudden stratospheric warming?
-The ozone layer in the stratosphere plays a crucial role in absorbing ultraviolet radiation from the sun, protecting life on Earth. However, its direct role in sudden stratospheric warming is not explicitly mentioned in the script. The warming is more related to the dynamics of the polar night jet and the temperature changes in the stratosphere.

Outlines

00:00

🌨️ Sudden Stratospheric Warming and Its Impact on Winter Weather

The script discusses the phenomenon of sudden stratospheric warming (SSW) as a contributing factor to unusually cold and snowy winters in the Northern Hemisphere. It explains the atmospheric structure, with the troposphere being the lower, weather-active layer and the stratosphere above it, which is typically cold and dry. During polar night, the stratosphere can become extremely cold, leading to strong westerly winds known as the polar night jet. Disturbances from the troposphere can cause this jet to wobble and, in severe cases, reverse direction, leading to SSW. This event is characterized by a rapid increase in temperature, as illustrated in the provided graph, which shows a dramatic rise in stratospheric temperatures over a few days. The script also explains how SSW can lead to the weakening of the Jetstream, allowing high-pressure systems to form and potentially causing cold snaps and heavy snowfall. However, it notes that SSW is not a definitive predictor of cold weather, as only about two-thirds of SSW events result in subsequent cold snaps.

Mindmap

Keywords

💡Sudden Stratospheric Warming

Sudden stratospheric warming (SSW) is a meteorological phenomenon where the polar stratosphere temperature rises dramatically, sometimes by 30 or 40 degrees Celsius within a few days. In the video, SSW is explained as a key reason for unusually cold and snowy winters in the Northern Hemisphere, as it disrupts the polar night jet and can influence weather patterns in the troposphere.

💡Troposphere

The troposphere is the lowest layer of Earth's atmosphere, extending from the surface up to about 10 kilometers. It is where most weather events occur, including clouds, rain, and wind. The video highlights the troposphere as the atmospheric layer directly involved in the weather phenomena we experience daily.

💡Stratosphere

The stratosphere is the atmospheric layer above the troposphere, characterized by thinner, drier air and minimal cloud cover. It contains the ozone layer and plays a significant role in sudden stratospheric warming events, which can influence weather patterns lower down in the troposphere.

💡Polar Night Jet

The polar night jet is a ring of strong westerly winds that forms around the cold air over the polar region during the polar night. In the video, the polar night jet's disturbance and subsequent weakening are linked to sudden stratospheric warming events, which can lead to significant changes in weather patterns.

💡Westerly Winds

Westerly winds are winds that blow from the west to the east. In the context of the video, the strong westerly winds of the polar night jet can weaken and even reverse direction during sudden stratospheric warming events, leading to potential cold snaps in the lower atmosphere.

💡Easterly Winds

Easterly winds blow from the east to the west. The video describes how, during sudden stratospheric warming events, the westerly winds can reverse to easterly winds, contributing to the weakening of the Jetstream and the onset of colder weather conditions.

💡Jetstream

The Jetstream is a fast-flowing, narrow air current found in the upper levels of the atmosphere. It typically flows from west to east and influences weather systems. The video explains that a weakened Jetstream due to sudden stratospheric warming can lead to the formation of blocking highs, which can cause cold weather outbreaks.

💡Blocking Highs

Blocking highs are high-pressure systems that can disrupt the normal flow of the Jetstream, leading to prolonged periods of certain weather conditions, such as cold spells. In the video, blocking highs are described as a consequence of sudden stratospheric warming, allowing cold Arctic winds to reach lower latitudes.

💡Polar Night

The polar night is a period during winter in polar regions when the sun does not rise above the horizon, leading to continuous darkness and extremely cold temperatures. The video mentions the polar night as the time when the air over the pole becomes very cold, contributing to the formation of the polar night jet.

💡Ozone Layer

The ozone layer is a region of Earth's stratosphere that contains a high concentration of ozone, which absorbs most of the sun's ultraviolet radiation. While not the main focus of the video, the ozone layer is mentioned as part of the stratosphere, highlighting the different atmospheric layers involved in sudden stratospheric warming events.

Highlights

Unusually cold and snowy winters in the Northern Hemisphere are partly due to sudden stratospheric warming.

The atmosphere is divided into the troposphere and stratosphere, with weather occurring mainly in the troposphere.

The stratosphere is characterized by thin, dry air, the absence of clouds, and the presence of the ozone layer.

Polar night leads to extremely cold temperatures in the stratosphere, reaching as low as minus 70 or 80 degrees Celsius.

Strong westerly winds form a ring around the cold air pole, known as the polar night jet.

Disturbances from the troposphere can affect the polar night jet, causing it to wobble.

Large wobbles in the polar night jet can lead to a weakening and even reversal of wind direction to easterly.

When the polar night jet weakens, cold stratospheric air collapses and warms rapidly, resulting in sudden stratospheric warming.

Sudden stratospheric warming can cause a dramatic increase in temperature, up to 30 or 40 degrees Celsius in just a few days.

The phenomenon of sudden stratospheric warming occurs high in the atmosphere and can affect weather patterns.

Reversed easterly winds can descend into the lower atmosphere, impacting the Jetstream and weather systems.

Weakening of the Jetstream can lead to the formation of blocking highs, altering typical weather patterns.

Blocking highs allow cold surface winds to escape the Arctic, potentially bringing frost and heavy snow.

Sudden stratospheric warming can be an indicator of an impending cold snap but is not a definitive predictor.

Only about two out of three warming events result in a subsequent cold snap.