People love hill stations. Especially the people living in equatorial regions, where the sun is blazing down on them, do love to take a trip to the beautiful hill stations and spend a couple of days there. The perpetual cold climate is what attracts everyone to the hill stations. But what is the reason behind the relatively colder climate in hill stations even while the plains are scorching in the summer heat?
There are a number of factors that affect the distribution of climate around the world; altitude, winds, proximity of sea, the rotation of earth and so on. The parameter that affects the atmospheric temperature the most is the altitude of the place.
The temperature is closely related to pressure. The first thing you would need to know is that the atmospheric pressure is very low in higher altitudes. This is due to somewhat the absence or the lower amount of air there. The air is actually a combination of various gases such as Oxygen and Nitrogen and water vapor. It has weight, and the atmospheric pressure at a place is simply the force that the air particles exert on that particular place. The gravitational pull of Earth forces the air constituents to be as close to the planet surface as possible. And owing to this, the higher places have a lot less amount of air than the sea level; that is, the density of air is less in higher altitudes. Less density means less amount of gas per unit volume. Since temperature is the average energy of the particles per unit volume, it will be lower in higher regions.
The heating process of Earth also contributes to this phenomenon. The sun doesn’t heat the air directly. It actually heats the surface of Earth. When the surface gets warmed up, it further heats up the layer of air above it. This air gets enough kinetic energy to move and rises up in the air, expanding in volume. The expansion means the decrease in its density. Hence, the temperature would have been reduced by the time they get to higher parts of the atmosphere.
Scientific studies have revealed that the atmospheric temperature register a decline by an average of 6.5 degree Celsius by every 1000 meters. This is called lapse rate. It varies according to regions, though. The other factors such as winds and proximity of sea also affect the temperature.
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