- Air in Natural Motion as that moving horizontally at any velocity along the surface.
- Three broad categories are :-
- Regular Winds / Prevailing winds / plarentry winds. (E.g. Trade winds, Westerlies and Polar Easterlies).
- Periodically Winds (Which blow seasonally) :- Monsson
- Variable Winds : Cyclone and other local winds.
Trade Winds :-
- Trade in German means Track. To blow trade means to blow steadily in the same direction and in a constant course.
- These are steady current of air blowing from the sub- tropical high pressure belts coriolis force they blow from the north - East in the northern hemisphere and from the South- East in the southern hemisphere.
Westerlies :-
- Blow from sub tropical high pressure to sub poler low pressure belt, westerly wind flow 30 degree to 35 degree north to south and 60 degree to 65 degree latitude from the hemisphere.
- In the Northern hemisphere, land masses causes considerable disruption in the westerly wind belt. But between 40 degree and 60 degree live the almost unbroken Ocean belt. Rationalize are strong and persistent hair giving price to mariners expressions. 'Roaring forties, Furious fifties and 'Shrieking sixties.
Polar Easterlies :-
- More from high pressure poles to sub polar low pressures areas.
- These are affected by the earth's rotation to become East winds over the polar easterlies.
Local Winds :-
Chinook.:- Hot, dry winds in Rockies, also called 'snow eater.
Foehn . :- Hot, dry winds in the Alps.
Khamsin :- Hot, dry winds in Egypt.
Siracco :- Hot, moist wind from Sahara to Mediterranean Sea.
Solano :- Hot, moist wind from Sahara towards Iberian Peninsula
Harmattan :- Hot, dry winds blowing outwords from the interior of West Africa, also called 'Guineo Doctor'.
Bora :- Cold, dry winds blowing outwords from Hungary to the North of Itley ( near Adriatic sea.)
Punas :- Cold, dry winds blowing downward the western sides of Andes.
Brick fielder :- Hot dry winds in Australia.
Purga :- Cold, wind in Russian tundra.
Levanter :- Cold, wind in Spian.
Norwester :- Hot winds in New Zealand.
Santa Ana :- Hot, winds in Southern California in USA.
Blizzard :- Very cold winds in Tundra region.
Cyclones & Anticyclones :-
- It is a system of very low pressure in the center surrounded by increasingly high pressure outwards. In this, the winds blows in a circular manner. Anti clock wise direDirec in Northern Hemispheres. Clock wise direction in the southern Hemisphere.
- It is a system of very high pressure in the center. Surrounded by decreasing low pressure out words.
- In this temperature region, they occur due to the coming close and imperfect mixing of two masses of air of contrasting temperature and humidity condition. Cycles of this type are also known as (waves Cyclone or temprate Cyclone).
- On the other hand, In the tropiTro region, they occur during to intense heating up of air in some regions causing very low preepres in thses location. Tropical seas and oceans are most conductive of the development of tropical cyclone.
- Tornadoes are very strong tropical cyclone of a Smaller size. They are especially feared in the Mississippi Valley in US and here they called Twister. They differ from cyclone in that they generally develop over land. They are more destructive then cyclone as the speed. Of winds is very high, exxedding 320 km per hour.
Tropical Cyclone :-
- Cyclone - in the Indian Ocean.
- Hurricane - in the Caribbean Island.
- Typhoons - in the China Sea.
- Willy-Willies - in the North West Australia.
- Tornadoes - in the coastal US.
- Twister - in Mississippi Valley USA.
Anticyclones :-
- They are opposite to cyclone in all respect. They are the centre of high pressure with gentle outward flow of air.
- The air circulation is clock wise in the Northern Hemispheres and the anti clock wise in the Southern Hemisphere.
- Weather associated with and Anticyclones is fair weather.
