This presentation discusses geostrophic wind and related concepts. It defines the Coriolis force, pressure gradient force, centrifugal force, centripetal force, and geostrophic wind. The Coriolis force causes deflections in winds blowing across the Earth's surface. Pressure gradient force drives wind from high to low pressure. Geostrophic wind blows parallel to isobars in balance with the Coriolis force. Gradient wind occurs aloft where winds flow through curved height contours, remaining parallel to them. Examples are given to illustrate gradient wind. Balanced flow speeds are shown for geostrophic, gradient, cyclostrophic, and inertial winds under different conditions.

1. Geostrophic Wind
Gradient Wind
A Presentation
On

2. Group
number 5Name Roll no
Mahmudul
Hasan
MD.Liton Khan
Mst.Sanjida Akhter
MD.Omar Faruk
Shahriar Sagor
1731023
1731048
1731050
1731051
1731055
Reg No
2263
2288
2290
2291
2295

3. Group
number 5
Name Roll no
Nahida Rahman
MD.Sakib Hasan
MD.Shawon Hossain
MD.Alamin Khan
MD.Rafsan Hossain khan
1731049
1731054
1731053
1731052
1731055
Reg No
2289
2294
2293
2292
2295

4. Context
Pressure Gradient
Force
Coriolis Force
Gradient Wind
Centrifugal &
Centripetal Forces
Geostrophic Wind

5. Coriolis Force
The Coriolis force is a force which acts
upon any moving body in an
independently rotating system.The
most well known application of the coriolis
force is for the movement or
flow of air across the earth

6. The effect is named after the
French physicist Gaspard de
Gustave Coriolis (1792-1843),
who first analyzed the
phenomenon mathematically.
Who discovered this!!!!!

7. The Earth rotates about its axis from west to
east once every 24 hours. Consequently, an
object moving above the Earth in a generally
northerly or southerly direction, and with a
constant speed relative to space, will be
deflected in relation to the rotation of the
Earth.

8.  This deflection is clockwise, or to
the right, in the Northern Hemisphere
 This deflection is anticlockwise, or to
the left, in the Southern
Hemisphere.

9. Clockwise
Anti
Clockwise

10. The way of coriolis force

11. Pressure Gradient Force
Pressure differences must create a force in
order to drive the wind. This force is the
pressure gradient force
The force is from higher pressure to
lower pressure and is perpendicular to
isobars or contours

12.  Whenever a pressure difference develops over an
area, the pressure gradient force begins moving
the air directly across the isobars
 The closer the spacing of isobars, the stronger is
the pressure gradient force
 The stronger the pressure gradient here force, the
stronger is the wind

13. The flow of air

14. the pressure gradient force is balanced
by the gravitational force, maintaining
hydrostatic equilibrium. In Earth's
atmosphere, for example, air pressure
decreases at altitudes above Earth's
surface, thus providing a pressure gradient
force which counteracts the force of gravity
on the atmosphere.

15. Pressure gradient force

16. Geostrophic wind describes a steady-state of
flow in a spatially varying pressure field when
Geostrophic wind
 frictional effects are neglected; and
 the entire pressure gradient exactly
balances the Coriolis force alone
(resulting in no curvature).

17. Isobars
The Isobars are lines of equal pressure
the pressure values are given in millibars.

18. Geostrophic wind
 A wind that flows parallel to the isobars

19. Geostrophic balance
Northern hemisphere Southern hemisphere

20. The conception of centrifugal force has evolved
since the time of Huygens, Newton, Leibniz,
and Hooke who expressed early conceptions of
it. Its modern conception as a fictitious force
arising in a rotating reference frame evolved in
the eighteenth and nineteenth centuries
Centrifugal Force

21. The concept of centrifugal force can be
applied in rotating devices, such
as centrifuges, centrifugal
pumps, centrifugal governors,
and centrifugal clutches, and
in centrifugal railways, planetary
orbits and banked curves, when they are
analyzed in a rotating coordinate system.

22. Centripetal Force
Isaac Newton described it as "a force by which
bodies are drawn or impelled, or in any way
tend, towards a point as to a centre". In
Newtonian mechanics, gravity provides the
centripetal force responsible for astronomical
orbits

23. The Centrifugal force and Centripetal force
are closely related with each other

24. Gradient Wind
The gradient wind is a balance of the Pressure
Gradient Force, centrifugal and Coriolis
A geostrophic wind becomes a gradient wind
when the wind begins flowing through curved
height contours

25. The gradient wind occurs aloft (no
friction) within curved height
contours. The wind stays parallel to
the height contours throughout the
curve. The two examples will be
used to show how the flow stays
parallel to the height contours.

26. Example 1
Example 2

27. Geostrophic Cyclostrophic Inertial
Gradient (H-
pressure)
Gradie
nt (L-
pressu
re)
R=100 km 7.45 9.25 11.50 N/A 5.15
R=300 km 7.45 16.00 34.50 10.90 6.30
https://en.wikipedia.org/wiki/Balanced_flowsource
The chart shows how the different speeds change in the conditions
chosen above and with increasing radius of curvature.
Taking two of such distances R as 100 km
and 300 km, the speeds are (in m/s)

28. Balanced-flow speeds compared
Each balanced-flow idealisation gives a different estimate
for the wind speed in the same conditions. Here we focus
on the schematisations valid in the upper atmosphere

29. So we learned about
Coriolis Force
Gradient Wind
Centrifugal & Centripetal force
Pressure Gradient Force
Geostrophic Wind

30. THANK YOU ALL

31. Any Questions ?