World Geography / Climatology
Classification of winds is done based on both global as well as local phenomena. Winds can be permanent or temporary in nature. There are
3 types of winds in the world namely, Primary, Secondary and Tertiary winds.
Primary winds are nothing but the Global or Permanent or Planetary winds. These are
classified into 3 types of winds namely, Trade winds, Westerlies and Polar Easterlies.
These are also known as Seasonal Winds or Periodic Winds. They are confined to a particular area and to a particular season. They change their
direction with season. These are quite strong winds. Example of such Secondary
winds is Monsoonal Wind system in Indian ocean. Other examples of periodic winds are Sea Breeze and Land Breeze, Mountain Breeze and Valley Breeze, etc.
Monsoon Wind System
- During the summer, when the Sun is in Northern hemisphere, an intense low pressure zone is created in the northern region of the Indian subcontinent.
Because of this low pressure zone, the Trade winds of the southern hemisphere are pulled towards the North.
- These Trade winds are deflected to their right while crossing the Equator because of Coriolis force arising due to Earth's rotation. These winds are
responsible for south-west monsoon in Indian subcontinent and the adjacent surrounding areas.
- As they travel over the Indian Ocean for a large distance before they reach the land, they are very much saturated with moisture and induce heavy
rainfall in the Indian subcontinent and the adjacent neighboring
- During the winter, the weather conditions are exactly reversed. During winter, a high pressure zone is created in the northern region of the Indian
subcontinent and winds start to flow southwards towards the Equator because of the low pressure region that is created by the southward movement of the
Sun. These winds are responsible for north-east monsoon in India.
Sea Breeze and Land Breeze
They are formed at the coast and formed within a day due to thermal and pressure gradient between sea and land. Because of higher specific heat, sea
cools and heats slowly and because of low specific heat, land cools and heats rapidly. During the day time, land rapidly heats up and hence
temperature increases and pressure decreases and sea heats up slowly and hence temperature decreases and pressure increases. During the day winds blow
from the sea to the land which are called sea breeze (cool). During the night, there is reversal in phenomenon and are called land breeze
Mountain Breeze and Valley Breeze
In mountainous region, there is Mountain Breeze Valley Breeze phenomenon very much similar to Sea Breeze Land Breeze. During the day time, the
valleys will be hot when compared to the mountains and hence air flows up the slopes from the valley towards the mountains which is called Valley Breeze.
During the nights, the phenomenon is reversed and cool air slides down from mountain peaks to valleys which is called Mountain Breeze.
Tertiary or Local Winds
Tertiary winds cover only small areas at a local level. They are formed due to local changes in temperature and pressure.
Different Types of Tertiary Winds
- Blizzards - They blow from North Pole to North Canada. These are strong cold chilly winds occurring during winter. They bring snow storms and life
comes to standstill because of these winds. Sometimes, they reach Central US plains where they are called Polar outbreaks.
- Chinooks - Along the slopes of Rocky Mountains, strong warm winds blow down in Western US known as Chinook winds or Snow Eaters (which melt
snow) during winter. These are crucial for ranching in Western US. Pastures are exposed because of these winds and become suitable for grazing.
- Santa Ana - These are strong hot dry and dust laden winds in summer near Mojave desert or Mexican desert. In Death valley, high temperature is due
to Santa Ana winds.
- Etesian or Meltemi - These are dry and strong northern winds that emanate from north Aegean Sea during the summer and having its effect felt in
Greece, Turkey and the surrounding areas. These winds are generally strong in the afternoons and calm down in the evenings.
- In the continent of South America, the names of different local winds are Zonda winds in Chile and Pampero winds in Argentina, Paraguay and
- From Morocco, Algeria and Tunisia hot and dry winds flow towards Mediterranean sea called Sirocco. Khamsin winds blow from Egypt to Red Sea.
Ghibli winds blow in Libya, Chad and Mauritania.
- From Sahara desert to Gulf of Guinea, winds called Harmattan, blow in summer hot. They are dry dust carrying storms. They bring small showers, which bring
down the temperature temporarily and people will have relief, hence they are sometimes called Doctor Harmattan.
- In Siberia in winter, strong winds called Burans blow out in different directions due to strong high pressure zone. These winds cannot reach India
because of Himalayas. When Buran winds reach China, Japan and Korea, the temperature will be below 00C. When they move to Iran also, the temperature
is below 00C.
- In Alps of Germany, Switzerland and Austria, strong and cold winds called Fohn or Foehn blow in winter.
- From Alps to Mediterranean sea, strong cold winds in winter called Mistral winds pass through Rhine Valley region. Citrus orchids are destroyed by
- In Arabian desert, the winds that blow are Simoon winds.
- In India, from March to May, there is strong convective winds blow during summer afternoons. Winds blow from West to East. Sometimes, they carry dust
storms and drizzles. They are called Loo in Punjab and Haryana. Andhi in Uttar Pradesh and Kal Baisakhi in Bihar and West Bengal. Exposure
to these winds is harmful and may result in sunstroke.
- In Deccan Plateau region of India, there will be Mango Showers in summer afternoons which are useful for increase in mango production. According to
the classification of winds, these winds are sometimes misconstrued as Secondary winds because they are often called pre-Monsoon showers but strictly speaking
they are not at all related to Monsoon.
- In South-Eastern Australia, Southerly Buster winds blow from New Zealand and Tasmania to Australia.