What is Wind?
The wind is the movement of air that has both direction and speed to it. It comprises gusts and eddies. An eddy is a whirl of air when wind encounters a solid object and forms and moves to the leeward side of the object. A gust can be described as a strong but sudden flow of wind.
Unlike natural phenomena like snowfall or rain, wind can only be felt and not seen. We feel its presence when it makes other things like trees, leaves, and dust move. The wind is measured using instruments such as a weathercock/weather vane.
What are the Types of Wind?
There are primarily three types of wind, namely Permanent wind, Local wind, and seasonal wind. The major stratification of the types of wind include permanent wind, local These have a further classification, which has been discussed below;
These winds blow throughout the year and are hence, called permanent winds. They follow a specific direction while blowing. Permanent wind can also be classified into three categories;
- Trade Winds: These permanent winds blow from east to west throughout the year in the equatorial region of the earth. The equatorial region is located between the 30°N and 30°S latitudes.
- Easterlies: True to their name, these are permanent winds that flow from the east. These are trade winds from the tropical areas and the prevailing winds from the polar areas.
- Westerlies: These are permanent winds that blow from the west to the east in the earth's middle latitudes. The middle latitudes are latitudes between 30° and 60°. Westerlies are also called anti-trades as they originate from higher-pressure areas (horse latitudes) and move toward the poles. They also bring extratropical cyclones.
The local wind is the type of wind that blows only in a specific time frame of a day or a year in a particular area. These winds can be classified into four sub-categories. They are as follows;
- Land Breeze: The type of wind that blows from the land toward the sea is called a land breeze. It blows usually at night.
- Sea Breeze: The type of wind that blows from a large water body toward the land is called a sea breeze. It occurs due to variations in the pressure of air which occurs due to variations in the heat capacity of water and dry land.
- Anabatic Winds: The type of wind that is sloped upwards and is driven by a warm surface temperature on a mountain slope are called Anabatic winds.
- Katabatic Winds: The type of wind that is down-sloped because of colder temperatures of the mountain surface are called Katabatic winds.
True to their name, seasonal winds are the types of winds that change their direction with the onset of differing seasons. A monsoon wind is the perfect example of a seasonal wind. The monsoon winds are the seasonally changing winds that change direction between summer and winter in the low-latitude regions of India.
Geographical Factors Affecting the Types of Wind
There are a few factors that affect the wind's flow and direction. The factors affecting the types of winds are pressure gradient force, Coriolis force/ deflection force, and Friction force generated by the surface. They have been listed and explained below;
- Pressure Gradient Force: This force is responsible for the initial direction and flow of the wind. The flow makes the air move from a high-pressure area to a low-pressure area. The direction is perpendicular to isobars. The relationship between wind velocity and pressure gradient force is directly proportional, which means that with the increase in wind velocity, there will also be an increase in its pressure gradient force and vice versa.
- Coriolis force/Deflection Force: This force is responsible for the deflection in the wind's direction and hence is also called ‘deflection force'.the deflection is towards the right in the northern hemisphere and towards the left in the southern hemisphere.
- Friction Force generated by surface: This force acts as a restraining force to the wind's flow. This friction is caused due to irregularities in the orientation of landforms. Friction is the most of terrains and the least on the surface of oceans. It is to be noted that the effect of this force is only effective for a few thousand kilometers from the surface of the earth.
Mechanism of the Wind System
Sun radiation affects of formation of the wind system. The earth's surface absorbs the Sun's radiation differently in different parts. This variation comes because of the different landscapes on the earth's surface. Valleys, sea surfaces, mountains, etc., absorb solar radiation on varying levels. This makes the air in some areas hotter than others and creates low atmospheric pressure. The colder air from other surfaces comes from the higher atmospheric pressure zone to the warmer and lower atmospheric pressure zone.
The varying terrains and the different atmospheric pressure zones are responsible for the difference in temperatures. And it is due to this difference that the wind occurs. There is a directly proportional relationship between the pressure difference and the airflow. The more the pressure difference, the faster the wind will flow. Winds balance out the unevenness between the distribution of pressure everywhere.
Local Winds of the World
The types of wind that circulate at a specified time period of the daytime are renowned to be the local winds. The four subcategories of the types of winds include the land breeze, sea breezes, anabatic winds, and katabatic winds. There are several local winds across the world. The name of local winds have been provided to you in the table below:
Types of winds [Local Winds of the World]
Central Africa and the Caribbean
Föhn or foehn
Alps, North Italy
Local Winds in India
India's weather and climate can be described as temperate to tropical. The country gets a decent amount of rainfall and has warm summer. Monsoon is a proper season in India. The months vary from state to state, governed by the seasonal winds of monsoon and demographical factors. The Indian summer monsoon usually lasts between the months of June to September. In these months, almost all parts of the country receive the most of their annual precipitation percentage. The monthly average totals up to 200-300 mm of rainfall across the country.
- One of the prominent local winds that flow through India is Loo. The Loo is a strong, gusty, dusty wind that brings about the hot and dry summers that we often associate the country with. Loo blows from the west, over the Indo-Gangetic Plain, towards the parts of Northern India and Pakistan. It blows quite strongly within the months of May and June.
- Loo is responsible for causing very low humidity in the atmosphere and higher temperatures. It has an extremely drying effect on crops that may brown in the areas that are worst hit by Loo.
- Kali Andhi is another such local wind in India. A violent dust storm happens before the monsoon in the northwestern parts of the Indo-Gangetic Plain region.
Types of Winds UPSC Questions
Wind and its types have become an important topic in your UPSC Syllabus under the subject of Geography. It is a static topic that can easily be mastered with practice. Below are some practice questions for you to attempt from the UPSC Prelims perspective.
Question - Which is a type of Permanent wind?
- Anabatic wind
- Katabatic wind
- Monsoon wind
Answer - C
Question - What is the local wind that blows in the countries of India and Pakistan?
Answer - A
Types of Winds UPSC
Types of wind are a relevant topic for your UPSC Exam preparation. It can be inquired about in the UPSC Prelims and UPSC Mains. Candidates can refer to appropriate Geography books for UPSC preparation to brush up on their basics about this topic.
Wind and the types fo winds is a static topic that holds a certain weightage in the syllabus for UPSC Prelims and UPSC Mains, and if your optional subject is Geography, this shall form to be one of the basic topics for you to cover. Candidates should refer to the appropriate book for the same.