What is sudden stratospheric warming? 640x480
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
🌨️ 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
💡Troposphere
💡Stratosphere
💡Polar Night Jet
💡Westerly Winds
💡Easterly Winds
💡Jetstream
💡Blocking Highs
💡Polar Night
💡Ozone Layer
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.
Transcripts
over the last few years many parts of
the Northern Hemisphere have had some
rather unusually cold and snowy winters
one of the reasons for that is something
called sudden stratospheric warming so
how does it work well let's start by
taking a look at a cross-section through
the atmosphere the lower level known as
the troposphere extends from around the
surface to about 10 kilometers and it's
where most of our weather actually takes
place above that we have the
stratosphere here the air is much
thinner much drier and is actually
little or no cloud it's also where we
find the ozone layer now during the
polar night the air across the pole or
over the top of the pole becomes very
very cold as no sunlight to warm it up
and in fact temperatures in the
stratosphere can fall as low as minus 70
or minus 80 degrees now around the edge
of that cold air we get a ring of strong
westerly winds for me that's known as
the polar night jet occasionally you'll
find the disturbance coming up from the
troposphere to affect that poni night
jet it makes it wave more makes it
wobble and when those wobbles get big
enough they actually start to break just
like waves breaking on a beach when that
happens the winds weaken and even
reverse direction around to an easterly
once the winds weaken that allows the
cold stratospheric air to collapse
downwards in towards the pole as it
collapses downwards it compresses and
warms rapidly and that's what we see as
sudden stratospheric warming
this graph shows just how dramatic that
warming can be the Green Line is the
average temperature in the stratosphere
but look at the red line that's the
actual temperature measurements and it
shoots up by 30 or 40 degrees Celsius in
the space of just two or three days but
remember all this is taking place high
up in the atmosphere sometimes though
those reversed winds those easterlies
can actually work the way down into the
lower atmosphere weakening the Jetstream
that normally pushes weather systems
from west to east instead high pressure
takes over we call these blocking highs
they allowed cold surface winds to
escape from the Arctic northerlies or
easterly's bringing the threat of hard
Frost and perhaps even heavy snow so a
sudden stratospheric warming can be a
useful sign that a cold snap is on the
way but it's not full
proof only about two out of three
warming event actually result in a
following cold snap
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