As a child, I watched movies about the extreme north and southern sultry tropics. And I was dreamed of going there to go there, move there to live there, to go there, it seemed that there was so good, so interesting, so Maniili is unusual for us. Snow expanses and southern colorful landscapes. Why does such a contrast of temperature and climate happen on earth?
Why on earth there is a spread of air temperature
The climate of a certain zone depends on the volume of solar energy, the movement of the air masses, the location relative to the oceans, on which the globe dominates, from the presence of warm and cold air flows.
The climate affects the features of the plant and animal world, also on a person. Due to the characteristics of the climate on Earth there are crop valleys, and sultry deserts, and the eternal cold zones.
The sun is the only source of light and heat for us, thanks to which there is life on Earth. Our planet revolves around the Sun on a certain trajectory - orbit, the sun simultaneously illuminates only one half of the globe, there will be a day, and on the other half - the night. The earth's surface is saturated with warm afternoon, and heating occurs unevenly.
The distribution of heat and light on the surface of the earth
The angle of falling sunlight in different places is different, and therefore various and the amount of heat obtained. On the equator, the sun rays fall vertically, and they heat the ground surface there. The farther from the equator, the angle of drops of rays becomes less, and therefore, the amount of heat decreases, and the air temperature drops.
The fact that the earth's axis is under the tilt, also affects the degree of warm-up with the sun of different zones. This is especially affected by the climate of medium latitudes, during the turnover of the Earth around the Sun allocate singular days:
- March 21 - Spring Equinox Day;
- September 23 - Day of autumn equinox;
- June 22 - Day Summer Solstice;
- December 22 - Winter Solstice Day.
Based on the resulting heat and illumination, the following belts are distinguished: the north polar, southern polar, tropical belt, the northern and southern moderate belt.
The atmosphere - the air sheath of the Earth
§ 40. Heat in the atmosphere (2)
Why in the morning and in the evening is colder than the day. Why in the tropics warmer than on the pole.
Every day the sun rises, rises to the maximum height, then decreases and finally hidden behind the horizon.
The less the angle of falling the sun's rays to the ground, the less heat it gets.
Carefully consider Figure 90. In the morning, in the afternoon and in the evening, the sun's rays fall on the surface of the earth at different angles. Therefore, the same amount of heat falls on different surface area. The maximum heating of the surface occurs in a sunny afternoon - when the sun reaches the greatest height above the horizon. This is confirmed observations of the daily course of air temperature. However, it takes time to heat the air from the surface of the Earth, so the greatest temperatures during the day are usually marked two hours after noon.
Air temperature during the day can change greatly. Over the oceans and seas, the daily amplitude of temperatures is usually small - only 1-2 ° C. Over the arid steppes and deserts it reaches 20 ° C and higher. The presence of decreases in the relief (basins, mountain valleys) increases the amount of daily fluctuations in temperature, and vegetation (especially forest) and cloudiness reduce. Remember that sometimes in the weather forecast you hear: "During the day, the air temperature will not change significantly." It happens in cloudy cloudy days, because the clouds delay the radiation of heat from the surface of the Earth, and the air is cooled significantly slower.
The daily course of air temperature depends on the change in the angle of falling the sun's rays during the day.
Why in the tropics is warmer than on the pole
Remember how the Sun illuminates our planet: his rays "rest" in the equator and "slide" at the poles.
The angle of falling the sun's rays depends on the latitude of the terrain.
We argue sequentially:
- The farther from the equator and the closer to the poles, the lower the sun over the horizon.
- The lower the sun over the horizon, the less the angle of falling the sunlight on the ground surface (Fig. 91).
- The smaller the angle of falling the rays, the less solar energy - light and heat - it comes from the unit of the surface of the earth.
In the days of equinoxes throughout the earth, the day is equal to the night. Therefore, the amount of solar energy per unit area depends on this day mainly from the latitude of the terrain (from the height of the Sun). On other days there is a role and duration of sunshine: after all, on different latitudes, the different length of the daylight.
Everyone knows that there is a permanent heat at the equator, but an eternal cold reigns on both poles.
Why is it going on? The point is several factors. To fully answer the question, it is necessary to take into account the shape of the Earth, its slope in relation to the Sun, the speed of rotation, oceanic flows, etc.
First of all, it is necessary to understand that heating depends on the angle of falling the sun's rays to the ground. At the equator, the rays fall at a large angle. At noon, the sun stands there right above the head of the observer. Straight rays very quickly and very well heat the surface, so there is always such heat in these places. Cool, for example, during the night period, the surface simply does not have time.
The farther from the equator and closer to the poles, the more spaces the solar rays fall on the surface. In this case, the oblique rays are heated by a more extensive territory, therefore most of the heat is lost. Under this angle, the rays seem to "slide" on the ground, and heat from it is much less, the surface does not have time to warm up.
It is also necessary to take into account the influence of ocean masses. Thanks to the strong heat, water in the equator evaporates faster, numerous clouds are formed at the top. All currents near the equator are always warm, they heatese those areas where this water falls. And did not have time to warm the water poles are always cold. The heat of oblique sunlight is not enough to warm in those places the earth and water. Therefore, in the polar and indoor areas, constant winter, the entire surface is always covered with snow and ice.
All cycle articles - what, how and why. - Read on our website.
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