PPT: Monsoon Jet Stream | Geography for UPSC CSE PDF Download

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Jet Stream
Page 2


Jet Stream
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Jet Stream
Geostrophic 
Wind
? The velocity and direction of the wind are the net result of the 
wind generating forces.
? The winds in the upper atmosphere, 2 – 3 km above the surface, 
are free from frictional effect of the surface and are controlled by 
the pressure gradient and the Coriolis force.
? However, as that air parcel begins to move, it is deflected by the 
Coriolis force to the right in the northern hemisphere (to the left 
in the southern hemisphere).
? As the wind gains speed, the deflection increases until the Coriolis 
force equals the pressure gradient force (2 – 3 km above the 
ground, friction is low and winds travel at greater speeds).
? At this point, the wind will be blowing parallel to the isobars 
(perpendicular to Pressure Gradient Force). When this happens, 
the wind is referred to as geostrophic wind.
Page 4


Jet Stream
Geostrophic 
Wind
? The velocity and direction of the wind are the net result of the 
wind generating forces.
? The winds in the upper atmosphere, 2 – 3 km above the surface, 
are free from frictional effect of the surface and are controlled by 
the pressure gradient and the Coriolis force.
? However, as that air parcel begins to move, it is deflected by the 
Coriolis force to the right in the northern hemisphere (to the left 
in the southern hemisphere).
? As the wind gains speed, the deflection increases until the Coriolis 
force equals the pressure gradient force (2 – 3 km above the 
ground, friction is low and winds travel at greater speeds).
? At this point, the wind will be blowing parallel to the isobars 
(perpendicular to Pressure Gradient Force). When this happens, 
the wind is referred to as geostrophic wind.
Page 5


Jet Stream
Geostrophic 
Wind
? The velocity and direction of the wind are the net result of the 
wind generating forces.
? The winds in the upper atmosphere, 2 – 3 km above the surface, 
are free from frictional effect of the surface and are controlled by 
the pressure gradient and the Coriolis force.
? However, as that air parcel begins to move, it is deflected by the 
Coriolis force to the right in the northern hemisphere (to the left 
in the southern hemisphere).
? As the wind gains speed, the deflection increases until the Coriolis 
force equals the pressure gradient force (2 – 3 km above the 
ground, friction is low and winds travel at greater speeds).
? At this point, the wind will be blowing parallel to the isobars 
(perpendicular to Pressure Gradient Force). When this happens, 
the wind is referred to as geostrophic wind.
Jet streams
? Circumpolar (situated around or inhabiting around one of the 
earth’s poles),
? narrow, concentrated bands of
? meandering,
? upper tropospheric,
? high velocity,
? geostrophic streams,
? bounded by low speed winds and
? are a part of upper level westerlies.