What are Jet Streams?

                     Jet Streams

Jet Streams are circumpolar narrow concentrate brands of meandering at upper tropospheric level winds that circle around the earth with poles as their centers. The stream of air is very narrow (50-150km).

When the temperature contrast is maximum, jet stream flow in near straight path. But when temperature contrast reduces, the jet Stream starts to follow meandering path. 

Meandering depends on temperature contrast. 

Meander is called ridge if it towards poles and trough if it is towards equator.

Rossby waves 

* Meandering jet stream are called Rossby waves.

* Due to these waves cyclone and anticyclones exist. 

* These are formed when polar air moves towards equator while tropical air is poleward. 

Where Jet Streams flow? 

* Jet Streams flow just below the tropopause. 

* Polar Jet Streams flow 6 - 9km above the ground and sub - tropical jet Streams flows 10 - 16km above the ground. 

How jet Streams Affect weather in India?

* The polar front jet is produced by a temperature different and is closely related to affect weather in North - India during winters. 

* In summer its position shifts towards the poles and in winter toward the equator. 

* This jet is strong during winters. 

* This greatly influence climate conditions. 

* DUE TO LESS TEMPERATURE DIFFERENCE B/W EQUATOR & TEMPERATURE REGIONS DURING WINTER, JET STREAMS SHIFTED TOWARDS EQUATOR. 

* THIS CREATES LOW PRESSURE IN NORTH & CENTRE INDIA. 

* THE CORIOLIS EFFECT CREATES CYCLONE AND STORMS DUE TO JET STREAMS. 

* This results into rain and dust storms in North and central India regions like Delhi Rajasthan, Punjab, MP in December and January months. 

* When temperature difference increases jet Streams shifted towards poles and weather condition get normal.