Home » How Latitude and Altitude Affect Temperature

How Latitude and Altitude Affect Temperature

Temperature is the degree of hotness or coldness of a substance. Temperatures at the Earth surface vary from place to place, from night to day, and from summer to winter. It is directly related to the duration and intensity of solar radiation. The factors which influence variation in temperatures on the Earth include latitude, altitude, topography, vegetation and others. Lets learn more about how latitude and altitude affect temperature?

Effect of Latitude

The most important factor influencing the temperature of a place on the Earth is the latitudinal location. The temperature at a particular place is influenced by the angle of the solar radiation and the duration of daylight at that location. Both the angle of the solar radiation and the duration of daylight hours in a location change throughout the year as Earth revolves around the Sun.

The Earth takes about 24 hours to complete one rotation around its axis. The period of rotation is known as the Earth day. Day and night on the Earth occur due to this rotation. If the Earth does not rotate, then portion of the Earth facing the Sun would always experience day (thus remain warm all the time). The other half would remain in darkness (thus remain cold all the time). Earth is tilted on its axis of rotation by 23.4°. This tilt is responsible for the seasonal variations in temperature and day length.

how latitude and altitude affect temperature

Figure 1: How Latitude and Altitude Affect Temperature posts figure shows the day and night rotation of the earth.

The second motion of the Earth around the Sun in its orbit is called revolution. It takes 365 days and six hours (one year) to revolve around the Sun in an elliptical orbit. The direction of rotation and tilt on its axis of rotation do not change as Earth revolves around the Sun. Seasons change due to the change in the position of the Earth around the Sun. As shown in the figure, on 21st June, the Northern Hemisphere is tilted towards the Sun. The rays of the Sun fall directly (i.e. perpendicularly) on the Tropic of Cancer. The North Pole is inclined towards the Sun and the places beyond the Arctic Circle experience continuous daylight for about six months.

how latitude and altitude affect temperature

Since a large portion of the Northern Hemisphere is getting light from the Sun, it is summer in the regions north of the equator. The longest day and the shortest night at these places occur on 21st June. At this time in the Southern Hemisphere, all these conditions are reversed. It is winter season there. The nights are longer than the days. This position of the Earth is called the Summer Solstice. The combination of more direct rays of sunlight and more hours of daylight causes the hemisphere tilted toward the Sun to receive more solar radiation and to have warmer temperatures.

Figure 2: How Latitude and Altitude Affect Temperature Explains the Inclination of the Sun at Summer Solstice. The Sun is directly (90°) over the Tropic of Cancer and is at 66.5° over the equator. At this time, the area above the Arctic Circle is in light 24 hours a day, while the area below the Antarctic Circle is in darkness 24 hours a day.

When the incoming solar radiation is nearly perpendicular, the solar radiation is concentrated over a smaller surface area, causing high temperatures. At higher latitudes, the angle of solar radiation is smaller, causing solar radiation to spread over a larger surface area, causing lower temperatures.

Because the angle of solar radiation varies depending on the latitude, surface temperatures on average are warmer at lower latitudes and cooler at higher latitudes. Apart from the angle at which solar radiation strikes the Earth surface, the distance that a beam of light travels through the Earth’s atmosphere before it reaches the Earth’s surface also influences the temperature. A beam of solar radiation passing through the atmosphere at the equator travels through less thick atmosphere than incoming solar radiation arriving at higher latitudes. As incoming solar radiation travels through thicker atmosphere, there is a greater chance for reflection and scattering of solar radiation, thus reducing the insolation at the Earth’s surface. On 22nd December, the Tropic of Capricorn receives direct rays of the Sun as the South Pole tilts towards it. As the solar radiations fall vertically at the Tropic of Capricorn, a larger portion of the Southern Hemisphere gets light. Therefore, it is summer in the Southern Hemisphere with longer days and shorter nights. The reverse happens in the Northern Hemisphere. This position of the Earth is called the Winter Solstice.

On 21st March and September 23rd, direct rays of the Sun fall on the equator. At this position, neither of the poles is tilted towards the Sun; so, the whole Earth experiences equal days and equal nights. This is called an equinox. The Sun is directly (90°) over the equator and is at 66.5° at the Tropics of Cancer and Capricorn. At the equator, the duration of sunshine is 12 hours daily throughout the year. On 23rd September, it is autumn season in the Northern Hemisphere and spring season in the Southern Hemisphere. The opposite is the case on 21st March, when it is spring in the Northern Hemisphere and autumn in the Southern Hemisphere.

Effect of Altitude

In the troposphere, the temperature generally decreases with altitude. The temperature usually decreases with height at the average lapse rate of 6.5°C per kilometre. The troposphere is about 12 kilometres thick on average; it is thicker in summer than in winter. The troposphere over the equator is about 18 kilometres thick, while its thickness in the regions nearest the two poles is only about eight to nine kilometres. Although the sunlight comes from the top to the bottom of the atmosphere, the troposphere is primarily heated from the bottom. The reason is that the troposphere’s gases absorb very little of the incoming solar radiation. Instead, the ground absorbs this radiation and then heats the tropospheric air by conduction and convection. Since the Earth’s surface is the primary heat source, heating is most effective near the ground, the temperature in the troposphere gradually decreases with increasing altitude.

FAQ

FAQs on how latitude and altitude affect temperature

Climate is affected by altitude since higher altitudes have a more severe and chilly climate. Additionally, the closer the latitude is to 0 degrees, the warmer the temperature and the higher the relative humidity.

Climate is affected by altitude since higher altitudes have a more severe and chilly climate. Additionally, the closer the latitude is to 0 degrees, the warmer the temperature and the higher the relative humidity.