Solar Constant - Wikipedia ~ Online encyclopedia

Scientists call this quantity "total solar irradiance," shown here in Watts per square meter (W/m2). Space-based measurements, begun in 1978, indicate Earth receives an average of 1,361 W/m2 of incoming sunlight, an amount that has varied in the recent past by about 1 W/m2 (or one-tenth of one percent) on roughly 11-year cycles.At Earth's average distance from the Sun (about 150 million kilometers), the average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter, according to measurements made by the most recent NASA satellite missions. This amount of power is known as the total solar irradiance.Earth from the sun (1.5 x 1011 m) S = L / (4 p d2) = (3.9 x 1026 W) / [4 x 3.14 x (1.5 x 1011 m)2] = 1370 W/m2 ESS200A Prof. Jin-Yi Yu Solar Energy Incident On the Earth qSolar energy incident on the Earth = total amount of solar energy can be absorbed by Earth = (Solar constant) x (Shadow Area) = S x p R2 Earth ESS200A Prof. Jin-Yi YuAlmost all energy at Earth's surface comes from the Sun. The Sun's energy heats the planet and the air around it. This causes the atmosphere to move and create weather. Sunlight also powers photosynthesis and life on Earth.The sun provides all the energy that is utilized within the earth although most of the sun's energy never reaches the planet's surface. The heat that the earth receives goes into five distinct components of the environment: living things such as plants and animals, the earth's crust, the earth's water bodies, the atmosphere, and the ice.

Climate and Earth's Energy Budget

The Sun is the major source of energy and vital to life on Earth, but much of its light is reflected. Solar energy acts as a primary energy flow that can be harnessed. Almost all of the Earth 's energy input comes from the sun. Not all of the sunlight that strikes the top of the atmosphere is converted into energy at the surface of the Earth.So the energy flux heating the surface is about 340 Watts/cm^2. At the earth's distance from the sun of 147 million kilometers and a solar luminosity of 4 x 10^33 ergs/sec we get a flux of 1.8 Watts/cm^2. The interior of the earth contributes more than 99.5 percent of the total heating of the surface compared with the sun!would be completely offset, and the world energy consumption rate would remain at 13.5 TW. At the other extreme, if energy intensity were not to decrease at all, the increase in population and per capita GDP would cause the world energy consumption rate to increase to 13.5 TW · 1.02283(2050-2001) = 40.8 TW by 2050.The amount of solar energy that Earth receives has followed the Sun's natural 11-year cycle of small ups and downs with no net increase since the 1950s. Over the same period, global temperature has risen markedly. It is therefore extremely unlikely that the Sun has caused the observed global temperature warming trend over the past half-century.

PDF Solar Flux and Flux Density Solar Flux Density Reaching Earth

To put that in numbers, from the US Department of Energy: Each hour 430 quintillion Joules of energy from the sun hits the Earth. That's 430 with 18 zeroes after it! In comparison, the total amount...The sun provides more energy in an hour than the United States can use in a year! About 30 percent of the radiant energy that reaches the Earth is reflected back into space. About half of the radiant energy is absorbed by land and oceans. The rest is absorbed by the atmosphere and clouds in the greenhouse effect.Once the Sun's energy reaches Earth, it is intercepted first by the atmosphere. A small part of the Sun's energy is directly absorbed, particularly by certain gases such as ozone and water vapor. Some of the Sun's energy is reflected back to space by clouds and Earth's surface.The Earth receives a large amount of energy from the Sun, over 1.7 x 10 17 joules every second (or 1.7 x 10 17 Watts), and it is this energy that results in a warm, livable planet. However, only a certain amount of this energy is absorbed by the atmosphere and used to heat the Earth.Credit: NASA We can describe the amount of the Sun's energy reaching Earth as 1 solar constant. The average distance from the Sun to Earth is 149,597,870.66 kilometers (92,955,807.25 miles) which we can simplify to what astronomers call 1 Astronomical Unit or 1 AU. So Earth is 1 AU from the Sun and receives 1 solar constant.

The earth-atmosphere energy stability is the stability between incoming energy from the Sun and outgoing energy from the Earth. Energy released from the Sun is emitted as shortwave gentle and ultraviolet energy. When it reaches the Earth, some is mirrored back to house by means of clouds, some is absorbed by the ambiance, and a few is absorbed at the Earth's surface.

Learning Lesson: Canned Heat

However, since the Earth is much cooler than the Sun, its radiating energy is way weaker (lengthy wavelength) infrared energy. We can indirectly see this energy radiate into the environment as warmth, rising from a sizzling highway, creating shimmers on hot sunny days.

The earth-atmosphere energy balance is accomplished as the energy received from the Sun balances the energy lost via the Earth back into area. In this fashion, the Earth maintains a stable average temperature and therefore a solid climate. Using 100 devices of energy from the sun as a baseline the energy balance is as follows:

At the best of the environment - Incoming energy from the sun balanced with outgoing energy from the earth. Incoming energy Outgoing energy Units Source Units Source +100 Shortwave radiation from the sun. -23 Shortwave radiation mirrored again to area via clouds. -7 Shortwave radiation mirrored to house by way of the earth's floor. -49 Longwave radiation from the ambiance into house. -9 Longwave radiation from clouds into house. -12 Longwave radiation from the earth's floor into house. +100 Total Incoming -100 Total Outgoing The environment itself - Energy into the atmosphere is balanced with outgoing energy from atmosphere. Incoming energy Outgoing energy Units Source Units Source +19 Absorbed shortwave radiation via gases in the environment. -9 Longwave radiation emitted to space by means of clouds. +4 Absorbed shortwave radiation by way of clouds. -49 Longwave radiation emitted to house by way of gases in atmosphere. +104 Absorbed longwave radiation from earth's surface. -98 Longwave radiation emitted to earth's floor by way of gases in environment. +5 From convective currents (rising air warms the atmosphere). +24 Condensation /Deposition of water vapor (warmth is launched into the atmosphere by means of process). +156 Total Incoming -156 Total Outgoing At the earth's surface - Energy absorbed is balanced with the energy released. Incoming energy Outgoing energy Units Source Units Source +47 Absorbed shortwave radiation from the sun. -116 Longwave radiation emitted through the surface. +98 Absorbed longwave radiation from gases in environment. -5 Removal of warmth via convection (emerging heat air). -24 Heat required through the processes of evaporation and sublimation and therefore removed from the surface. +145 Total Incoming -145 Total Outgoing

The absorption of infrared radiation seeking to escape from the Earth back to area is particularly important to the world energy stability. Energy absorption by the environment stores more energy near its surface than it could if there used to be no environment.

The reasonable surface temperature of the moon, which has no atmosphere, is 0°F (-18°C). By contrast, the moderate floor temperature of the Earth is 59°F (15°C). This heating effect is named the greenhouse effect.

Greenhouse warming is enhanced right through nights when the sky is overcast. Heat energy from the earth can also be trapped by way of clouds main to raised temperatures as compared to nights with transparent skies. The air is not allowed to chill as a lot with overcast skies. Under partly cloudy skies, some heat is authorized to escape and some stays trapped. Clear skies allow for the most cooling to take place.