WEATHER AND CLIMATE
The term weather describes the state of the air at a particular place and time - whether it is warm or cold, wet or dry, cloudy or windy. Weather describes whatever is happening outdoor in a given place at a given time. Weather is that change in the atmosphere which happens from minute to minute. The weather can change a lot within a very short time.
For example, it may rain for an hour and than become sunny and clear. Weather is what we hear about on the television news every night. Weather includes the daily changes in the temperature and wind conditions.
Weather is all around us, all the time. It is an important part of our lives and one that we cannot control. Instead, the weather often controls how and where we live, what we do, what we wear and what we eat. Climate and weather are often considered as same but they quite different from each other. The climate is the common, average weather conditions at a particular place over a long period of time. The climate tells us how hot, cold or wet it is likely to be in different parts of the world at different times of the year.
Different places of the world have different types of climate. Some regions are covered by thick layers of snow and ice. Some regions in the world have very hot and wet climate. The world can be divided into several major climatic regions on the basis of the prevailing climatic conditions.
What are the factors to determine the climate of a place?
The climate of a place is mainly dependent on the temperature of the sun. All living beings receive heat and light from the sun. The light and heat from the sun does not reach the earth in the same amount. Some places receive more heat and some get very less. There are several factors that determine the climate of a place. Like:
Distance from the equator
Distance from the sea
Humidity and rainfall
Height above the sea level
Direction of the winds
Distance from the Equator- The earth receives heat and light when the sun's rays fall on it. The rays of the sun fall on different parts of the earth. Near the Equator, these rays fall vertically and cover a small area. As we move from the Equator towards the pole, the rays become slanting and spread out over a larger area. This means that land near the Equator gets more heat that land near the tow poles. Days are also longer near the Equator than near the poles.
Height above the Sea Level-
Mountain regions are generally cooler than the plains. In very high mountains, there is always snowfall instead of rainfall. The peaks of the mountains are covered with snow and ice. This means that as we go higher and higher, the temperature decreases and air becomes thinner. the air with lower density absorbs less heat. So, at higher altitudes, the temperatures is lower than in the plains at the same latitude.
The temperature of Shimla is lower than Ludhiana, although they are of same distance away from the Equator. Thus, the higher a place is from the sea level, the cooler its climate will be.
Distance from the Sea- The climate of a place also depends on its distance from the sea. Let us compare the climate of Delhi and Mumbai. Delhi is located far away from the sea coast, while Mumbai is near to the sea coast. Delhi is very hot in the summer season and very cold in the winter season. On the other hand, Mumbai is neither very hot in summer nor very cold in winter.
We know that areas far away from the Equator have a lower temperature than those closer to it. This, Delhi should be cooler than Mumbai in the summer season because Delhi is far away from the Equator and Mumbai is closer to the Equator than Delhi, But this is not so. Why? This is because, Mumbai is near the sea coast. The cool air comes from the sea coast towards the land and makes its climate moderate. That is Why, Delhi has an extreme climate while Mumbai has a moderate climate.
Direction of the Winds- The climate of a place is also affected by the direction of the winds. Winds blow in particular directions in different parts of the world. They may be hot, dry, dusty, cool or full of moisture.
As for example, the winds coming from the Indian Ocean and the Arabian Sea bring clouds with them and cause rainfall all over India. The hot winds coming form the Thar Desert make Delhi very hot during summer. In this way, the climate of a place is influenced by the winds.
Humidity and Rainfall-The amount of moisture or water vapour present in the air is called humidity, Humidity also affects the climate of a place. Near the Equator, the water evaporates from the oceans by the sunlight and turns into vapour or steam. This water vapour or steam goes in the air and causes a lot of rain in to the area. That is why the climate near the Equator is hot and wet. The deserts have very little humidity, so there are very little rain throughout the year.
Climatic or Heat Zones
Depending on the amount of heat received, the earth is divided into three climatic or heat zones.
Torrid Zone- The Torrid Zone lies on both sides of the Equator, between the Tropic of Cancer and the Tropic of Capricorn. It is also called the Tropical Zone. The climate in this zone is hot and humid throughout the year.
Frigid Zone- The area lying between the Arctic Circle and the North Pole in the Northern Hemisphere and between the Antarctic Circle and South Pole in the Southern Hemisphere is called the Frigid Zone. The areas remain very cold and most parts are covered with snow throughout the year.
Temperate Zone-The area lying between the Torrid Zone and the Frigid Zone in both the hemispheres is called the Temperate Zone. The climate in this zone is mild-neither very hot nor very cold.
Now we can understand that various factors influence the climate of a place. If we know the distance from the Equator, height above the sea, distance from the sea and humidity and winds, we can know about the type of climate of any place.
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