Geostrophic wind & Gradient wind

this presentation is on several topics

1. Geostrophic Wind Gradient Wind A Presentation On

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

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

4. Context

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) Gradient (L-pressure) 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_flow source 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 ?