Earth surface wind system ppt.

This presentation basically gives information about Surface wind systems of Earth's atmosphere.

1. Earth’s Surface Wind Systems Presentation On: By- Ankit Abhilash Swain CUJ/M/2018/CEVS/06

2. Contents: Introduction Broad categories of Atmospheric motion Primary circulation Secondary circulation Tertiary circulation Earth Surface Wind System Doldrums Trade wind belts Prevailing westerlies Polar easterlies Conclusion References

3. Introduction The earth’s surface get differentially heated due to the varying amount of isolation received by it. Temperature difference thus produced account for the density difference that drives the atmosphere in 3-dimensional motion on globe. The general circulation of earth depends on many factors, like; Isolation Orbit of the earth Revolution of earth around sun Geographical conditions

4. Winds are the means by which atmosphere tries to balance out the uneven distribution of temperature over the earth surface. Besides the advectional transport of heat energy over the earth surface, winds also carry out water vapour from over the water bodies to land surface. Winds are generally of two types and flows in two regions: Equatorial region (progressively hotter) Polar region (progressively colder)

5. Broad Categories of Atmospheric Motion The earth atmospheric motion is generally categorised into three broad categories; Primary circulation Secondary circulation Tertiary circulation

6. Primary circulation: Macro-scale circulation. Includes planetary wind system(trade winds, westerlies and easterlies). Primary circulation pattern which prepare broad framework for other circulation patterns. Secondary circulation: Synoptic-scale circulation. Consist of cyclones, anticyclones, monsoon and air masses. Tertiary circulation: Both Meso-scale and micro-scale circulation. Includes the local winds which are produced by local causes and which only affect the weather and climate of particular locality or area.

7. Earth Surface Wind System This wind system is of primary type of atmospheric circulation. The earth surface wind system is divided into four types of wind pattern, i.e.; Doldrums Trade wind belts Prevailing westerlies Polar easterlies

8. The general scheme of circulation is shown in the figure.

9. Doldrums Equatorial belt of calm and variable wind lying over the equatorial region. Lies in between 5°N and 5°S latitude . Low pressure zone. Flow of wind is pole ward. Receives highest isolation. Meeting place of two trade winds, also called as Inter-tropical convergence zone .

10. Doldrums equator 5°N 5°S 0° Equatorial Low pressure zone 90°N 90°S

11. Trade wind belts Trade winds originate because of the pressure gradient from the sub-tropical belts of high pressure to the equatorial belt of low pressure. Also known as Horse latitudes . Extends from 5°to 30°of latitude in both of the hemisphere i.e.; northern and southern hemisphere. Wind flows equator ward. Winds from northern hemisphere are called as Northeast trade winds , similarly from southern hemisphere are called as Southeast trade winds . This zone is also called as Hadley cell .

12. Trade wind belts 5°N 5°S equator 0° 90°N 90°S 30°N 30°S 35°S 35°N Sub-tropical high pressure zone

13. Prevailing westerlies Lies between 30°and 60°latitude in each hemisphere i.e.; northern and southern hemisphere. Its move out from the pole ward margins of sub-tropical high-pressure belts. In northern hemisphere due to large percentage of land area with high mountains, plateaus and changing seasonal pressure system, the westerly flows is nearly observed. But in case of southern hemisphere, where there is preponderance of water over land, the westerlies are stronger and retain their direction persistency. In the southern hemisphere, between the latitude of 40°and 60°there is all water. Here the westerlies are powerful and persistence that the sailor used such expressions as, “roaring forties”, “furious fifties” and “screaming sixties” for these high velocity wind in the latitude belts of forties, fifties and sixties respectively.

14. 0° 30°N 60°N 60°s 30°S equator 90°N 90°S Prevailing westerlies Prevailing westerlies

15. Polar easterlies It moves out of the polar high towards the sub-polar low pressure belt. Lies between 60°and 90°latitude in each hemisphere. They flow from various direction and they are largely controlled by local weather distribution. Polar easterlies of the southern hemisphere are rather more coherent and well-defined.

16. 90°N 90°S equator 0° 60°N 65°N 60°S 65°S Polar easterlies Polar easterlies

17. Climatology, D. S Lal Balasubramanian , A. (2017). SCOPE OF STUDYING CLIMATOLOGY. 10.13140/RG.2.2.16027.77600. References

18. Thank You..