Why does the equator receive more sunlight and what happens to the temperature direction and humidity of the air at the equator?
The sunlight falls on different parts of the earth at different angles due to the spherical shape of the Earth. Direct and focussed sun rays fall on the equator and so, the regions here are hotter and warmer. Temperature decreases progressively from the equator towards the poles because it receives less sunlight.
Yes, Sunlight hits the Earth most directly at the Equator. The curve of the Earth means that sunlight is spread over a wider area the further you move from the Equator. Sunlight hits a smaller surface area at the Equator so heats up quickly compared to the poles. There is a difference in daylight according to latitude, but it is not because of proximity to the sun, and nor is there a significant difference in the total number of daylight hours in a year. What is different is that at the equator, the length of the day is nearly equal all year round. Due to the spherical shape of the Earth, sunlight falls on different parts at different angles. Direct and focused sun rays falls on the equator and hence, the regions here are hotter and warmer. The Polar Regions receive diffused sun rays, which is why the areas there are colder. Because the Earth is a sphere, the surface gets much more intense sunlight (heat) at the equator than at the poles. During the equinox, the Sun passes directly overhead at noon on the equator. Since the Sun is overhead the equator, the sunlight falls straight on the equator. On the other hand, the sunlight falls slant on the poles. This is due to the fact that the Earth is spherical in shape. This result in higher temperatures in the equator region of the Earth as compared to the poles. The Earth receives the most solar radiation at the Equator and the least solar radiation at the Poles. Therefore, the warm temperatures experienced at the Equator are due to the intense solar radiation that is experienced year round relative to the Poles.Lower latitudes experience more consistent lengths of daylight throughout the year. The equator always experiences 12 hours of daylight every day of the year. At the equator, all days of the year have the same number of hours of light and dark. Between the two tropics zones, which include the equator, the sun is directly overhead twice per year. Outside the tropic zones, whether to the south or north, the sun is never directly overhead. In the tropics, near the equator, warm air rises. When it gets about 10-15 km (6-9 miles) above the Earth surface it starts to flow away from the equator and towards the poles. Air that rose just north of the equator flows north. Air that rose just south of the equator flows south. Because the Equator receives the most solar heating, air rises in the equatorial region, creating a low-pressure region. Air from the equatorial region flows pole ward high in the atmosphere because there is a pressure gradient with the high pressure region at the Equator. So the air rising at the equator is warm and full of water vapor; as it rises into the upper atmosphere it cools, and the cool air can no longer hold as much water vapor, so the water condenses and forms rain. This is called the Coriolis Effect. The Coriolis Effect, in combination with an area of high pressure, causes the prevailing winds the trade winds to move from east to west on both sides of the equator across this 60-degree "belt."Average annual temperatures in equatorial lowlands are around 31 °C (88 °F) during the afternoon and 23 °C (73 °F) around sunrise. Rainfall is very high away from cold ocean current upwelling zones, from 2,500 to 3,500 mm (100 to 140 in) per year.The Earth receives the most solar radiation at the Equator and the least solar radiation at the Poles. Therefore, the warm temperatures experienced at the Equator are due to the intense solar radiation that is experienced year round relative to the Poles. Convection is this process where the warm air rises and cooler air sinks. At the equatorial region, you can find the tropical rain forests. The constant heat causes the air to rise. As air rises, it cools, condenses and forms clouds.
The equator receives more sunlight because the Earth is a sphere. The sun's rays strike the Earth's surface most directly at the equator, and the further you move away from the equator, the more slanted the sun's rays become. This means that the sun's rays have to travel through more of the atmosphere to reach the Earth's surface at the poles, and they lose some of their energy along the way.
The more direct sunlight the Earth's surface receives, the warmer it becomes. This is why the equator is the warmest part of the planet. The warm air at the equator rises, cools, and then flows back towards the poles. This creates the trade winds, which are the prevailing winds that blow from the east in the tropics.
The humidity of the air also increases at the equator. This is because the warm air can hold more water vapor than the cold air. The high humidity and warm temperatures at the equator create a tropical climate, which is characterized by lush vegetation and heavy rainfall.
Here are some of the specific things that happen to the temperature, direction, and humidity of the air at the equator:
- The temperature at the equator is warm all year round.
- The air at the equator rises, creating low pressure.
- The air flows from the high pressure areas at the poles to the low pressure area at the equator. This is called the trade winds.
- The humidity of the air at the equator is high.
- The air at the equator is often cloudy and rainy.
The equator is a very important part of the Earth's climate system. It is the source of the trade winds, which help to distribute heat and moisture around the planet. The equator is also home to many important ecosystems, such as the rainforests.
The equator receives maximum heat due to the shape of the earth. The earth is shaped in such a way that it is flattened at the tops (poles) and bulged out at the middle (equator), the sun's radiation hits the equatorial area at a right angle, and a smaller depth of the atmosphere penetrated by the insolation, hence lesser absorption and scattering. Whereas at the upper latitudes, the sun's radiation hits the surface at an oblique angle, and a larger depth of atmosphere is penetrated which translates to more absorption and scattering of heat.
Along the equator air is rising as it is warmed by solar radiation (section 8.2). Warm air contains more water vapor than cold air, which is why we experience humidity during the summer and not during the winter. The water content of air roughly doubles with every 10o C increase in temperature. Average annual temperatures in equatorial lowlands are around 31 °C (88 °F) during the afternoon and 23 °C (73 °F) around sunrise. In the tropics, near the equator, warm air rises. When it gets about 10-15 km (6-9 miles) above the Earth surface it starts to flow away from the equator and towards the poles. Air that rose just north of the equator flows north. Air that rose just south of the equator flows south. The abundance of energy reaching the equator produces hot humid air that raises high into the atmosphere. A low pressure area forms at the surface and a region of clouds forms at altitude. The air eventually stops rising and spreads north and south towards the Earth's poles. Consequently, the rising warm air at the equator becomes even less dense as it rises and its pressure decreases. An area of low pressure, therefore, exists over the equator. Warm air rises until it reaches a certain height at which it starts to spill over into surrounding areas. At the poles, the cold dense air sinks. The relative humidity is high near the equator because the actual vapor pressure is high. The relative humidity is high near the poles because the saturation vapor pressure is low.Since the Sun is overhead the equator, the sunlight falls straight on the equator. On the other hand, the sunlight falls slant on the poles. This is due to the fact that the Earth is spherical in shape. The higher temperatures in the equator region of the Earth as compared to the poles. Due to the spherical shape of the Earth, sunlight falls on different parts at different angles. Direct and focused sun rays falls on the equator and hence, the regions here are hotter and warmer. The Polar Regions receive diffused sun rays, which is why the areas there are colder.As air is warmed at the equator it becomes less dense and rises, while at the poles the cold air is denser and sinks. If the Earth was non-rotating, the warm air rising at the equator would reach the upper atmosphere and begin moving horizontally towards the poles. So the air rising at the equator is warm and full of water vapor; as it rises into the upper atmosphere it cools, and the cool air can no longer hold as much water vapor, so the water condenses and forms rain. Because the Earth is a sphere, the surface gets much more intense sunlight (heat) at the equator than at the poles. During the equinox (the time of year when the amount of daylight and nighttime are approximately equal), the Sun passes directly overhead at noon on the equator. It happens because of the Earth's orbit around the Sun. The equator receives less direct sunlight during the year. The equator receives about the same amount of direct sunlight all year long.
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