Jet streams? Must have seen it somewhere in your Class 9/10 Geography book however it might not have provided you the simple understanding of it we have tried our best to cover the underlying outline of that topic.
So what's basically a jet stream? Jet streams are geostrophic wind which blows horizontally in the upper layers of troposphere generally from west to east. So they are typically like a wind express which blows in the upper levels of the atmosphere like the Tropical Easterly Jet (TEJ) during South - West monsoon. TEJ itself is a type of jet stream which we will discuss later.
Having said that, jet streams form where air masses of lower and higher temperatures ( ranging temperatures) meet and extend from 20 degrees of latitude to the poles in both Northern and Southern hemispheres which basically means these streams are one of our regular weather phenomena which has a drastic impact in shaping weather dynamics.
GENESIS OF JET- STREAMS
Before going deep into the topic let's understand how the name"jet stream" came there is an interesting kutty story behind this we were amazed after going through this story, it was time of World War 2 America introduced first high altitude bomb plane #B-29 which flew at altitudes well above 20,000ft and air force meteorologists were assigned to give wind forecast.
The meteorologists then predicted a 193mph wind from the west at high altitude. Their commanding officer could not believe the estimate but on the next day, the B-29 pilots reported wind speeds of 196mph from the west. The term ‘jet-stream’ was first used by a German meteorologist, Heinrich Seilkopf, in 1939 thanks to this scientist even today after 83 years we are using this term "jet stream" now too. Regarding the genesis of jet streams interestingly this is classified into 3 major types based on gradients:
1)Thermal Gradient between Pole and Equator
2)Pressure Gradient between Pole and Equator
3) Pressure Gradient between Surface and Subsurface Area
Characteristics of jet streams:
Jet steam has several characteristics mainly categorised into six. We will see in brief about these characteristics one by one.
They are :
Speed: The jet stream typically moves at speeds of 110 to 220 mph (180 to 350 km/h).
Altitude: It is found in the stratosphere at an altitude of 6 to 10 miles (10 to 16 km).
Location: The jet stream is found near the boundaries of air masses with contrasting temperatures and can shift north or south depending on the seasons.
Path: The jet stream's path is typically wavy and its waves can influence the formation of storms.
Strength: The jet stream's strength is influenced by temperature differences and can affect the speed and direction of weather systems.
Persistence: The jet stream can persist for several days and its position can have a significant impact on weather patterns over large regions.
Diving into the types of jet streams they are broadly classified into 3 types:
1) Subtropical jet stream-
They mainly develop during winter and their maximum speed reaches 300 knots which is approximately 600 kmph (twice than a super cyclone). These indicate upcoming of fair weather where they pass over.
2)Tropical easterly jet stream (TEJ)-
They occurs near Troposphere south east Asia , India too during our summer season this implies the area above the jet remains hot whereas below the jet remains cold.
TEJ is one of the integral components of SW monsoon. More stronger the jet stream established more stronger the monsoon with respect to other factors favourable too during monsoon.
3)Polar night jet stream pass through upper stratosphere near poles which also indicate fair weather ahead in coming days.
Now that we have known what are jet streams and their types, genesis, characteristics. Let's ponder more on how these play crucial role in climatology.
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Types of Jet Streams |
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What is Jet Stream |
As mentioned in the above paragraphs, the jet stream has a key role in strengthening/ withdrawal of monsoon winds across the country. They also rent out to be the manufacturers of noctilucent clouds which are generally made up of ice crystals in the upper layer of atmosphere.
Interestingly, jet streams also tend to have bring over some ozone depleting substances owing to its high wind speeds along with them into the stratosphere which being one of the reasons for ozone depletion.
Also since jet streams contains express wind speeds if determined properly flying in and out through jet streams to travel in flights would reduce travel time and fuel cost as they deliver in more than 600km/h wind speeds. Thus could be nicknamed as (Natural Bullet train)
Heading back to its climatology impacts, during its movement with crust and trough formation it also impacts (intensifies) cyclonic and anticyclonic conditions. And to add upon, it also undergoes alternative expansion and compression (high pressure and low pressure) when the air mass moves down.
Coming to the end of the article, the topic of jet streams is a very brief one and we have tried to keep it as simple as possible for beginners/ people interested to understand the concept of streams.
Will come with another weather topic next week, until that cheers!
Post Created by:
Saran KTCC Weatherman
SSR-Sivasairaman
Vignesh