Why is temperature at the poles is much lower than on the equator
Answers
Answer:
This is because at poles, the sun rays are slanting.
Answer: This may help you
Explanation:
Why is temperature at the poles is much lower than on the equator?
=> As we climb up from ground level, it gets colder. There is an overall reduction in the air pressure, density and the temperature. The temperature is the most important property controlling the structure of our atmosphere.
The troposphere, the lowest layer of our atmosphere - extends upwards from the surface of the Earth and ranges in height from an average of 9 km at the poles, to 15 km at the Equator. It does not significantly absorb solar radiation. Instead, it is warmed by contact with the ground. The surface-heated air expands as it warms, becomes less dense than surrounding cooler air and so rises. This is what is known as "convection" and is the main process by which the troposphere heats up. However, as the warm air rises up, the pressure falls and so there is expansion needed to equalize its pressure with the air around it, with the result, the temperature drops. The air would mix, rise and descend, until its temperature is the same as the temperature of the surrounding air and a natural equilibrium is reached where the temperature falls smoothly with increasing height. This is known as the lapse rate, and is taken as 6.5°C per km. At an altitude of between 12 and 15 km, a minimum of -55°C is reached, this is the tropopause, the border between the troposphere and the stratosphere.
Above that altitude is the stratosphere, and the temperature starts to increase with altitude because the air at this level contains ozone which absorbs sunlight. Since the tropopause responds to the average temperature of the entire layer that lies underneath it, it is at its peak levels over the Equator, and reaches minimum heights over the poles. On account of this, the coolest layer in the atmosphere lies at about 15 km over the equator. The atmospheric temperature profile is latitude dependent. The tropopause height varies from about 15 km at the equator to only about 9 km at the poles. If we calculate the lapse rate of 6.5°C the temperature at 9 km altitude works out to roughly 38°C which is warmer than over the equator.
Due to the variation in starting height, the tropopause extremes are referred to as the equatorial tropopause and the polar tropopause.