What type of infrared radiation reaches earth

Both water and land reflect back some of that radiation to warm the atmosphere or other objects in contact with the surface.

The darker the object or surface, the faster it will absorb light and heat Air temperature is indirectly dependent on solar radiation. This effect occurs through heat transfer by conduction and convection Earth absorbs infrared radiation and converts it to thermal energy.

As the surface absorbs heat from the sun, it becomes warmer than the surrounding atmosphere. The heat is then transferred by conduction contact from the warmer Earth to the cooler atmosphere Air itself is a poor conductor of heat, so convection, or the rise and fall of warm and cool air, warms the rest of the atmosphere not in contact with the surface The rising warm air is often referred to as a thermal.

As the warmed air rises, cooler air sinks to the surface, where it continues in the convection process. This reflected radiation can be trapped and absorbed by gases in the atmosphere, or re-radiated back to the Earth This process is called the greenhouse effect.

Infrared light from the sun is absorbed by bodies of water and converted to heat energy. This low energy radiation excites electrons and warms the top layer of water. Nearly all infrared radiation is absorbed within one meter of the surface 1. This heat is then transferred to greater depths through movement from wind and convection 1. While heat is slowly transferred throughout the water column, it often does not reach all the way to the bottom. This is due to water column stratification.

In the ocean and many lakes, water can stratify, or form distinct layers of water. These layers are distinguished by their temperatures, densities and often different concentrations of dissolved substances such as salt or oxygen. The different water strata are separated by steep temperature gradients known as thermoclines 1. Photosynthesis is the process by which plants and other organisms, also known as photoautotrophs, use energy from sunlight to produce glucose.

This process can occur both on land and underwater Glucose is a kind of sugar that is later converted into Adenosine Triphosphate ATP via cellular respiration 3. ATP is an energy-bearing molecule that is used in the metabolic reactions of living organisms. This molecule is a necessity in almost all organisms 4. Photoautotrophs use sunlight, six carbon dioxide molecules, and twelve water molecules to produce one molecule of glucose, six oxygen molecules, and six water molecules.

This reaction reduces carbon dioxide levels in the air or water while producing glucose for ATP. Photosynthesis can occur underwater as long as enough light is available. In the ocean, significant amounts of photosynthetically active radiation can be detected as deep as m below the surface Within this euphotic zone sunlight zone , photosynthesis can occur.

This process only requires light, carbon dioxide, and water As long as a photosynthesizing organism, on land or underwater, has enough of these molecules, it can produce glucose and oxygen. Photosynthesis is a series of chemical reactions that occur with the help of enzymes. Enzymes are catalysts in biological processes and help speed up chemical reactions Photosynthesis also requires heat to activate the process.

As heat increases kinetic energy causing reactants to bump into one another more often , a higher temperature can speed up chemical reactions in addition to initiating the process Although increased temperatures can speed up photosynthesis, too much heat can be detrimental At a certain temperature, enzymes become denatured and lose their shapes.

Denatured enzymes no longer speed up chemical reactions and instead slow down photosynthesis. Thus temperature is an important factor in photosynthetic production, both in activating and maintaining the process. This is why there are different optimal temperatures for photosynthesis for different organisms 1.

Turbidity is a lack of water clarity caused by the presence of suspended particles 1. These particles absorb sunlight and can cause light to be reflected off the particles in water.

The more particles present in the water, the less photosynthetically active radiation that will be received by plants and phytoplankton. This loss of sunlight decreases the rate of photosynthesis.

If the photosynthetic production is limited, the dissolved oxygen level in the water will decrease In addition, turbidity can cause significant damage to water habitats by absorbing infrared radiation and increasing water temperature above normal levels. Visible light is the only band of light on the spectrum to be considered photosynthetically active. It has the perfect amount of energy to excite the electrons needed to start photosynthesis and not damage DNA or break bonds.

Ultraviolet can not be used for photosynthesis because it has too much energy. This energy breaks the bonds in molecules and can destroy DNA and other important structures in organisms 8. When plants and other photoautotrophs attempt to use UV-A nm for photosynthesis, electron transport efficiency is decreased, which in turn decreases the rate of photosynthesis 6.

On the other side of the spectrum, infrared light does not contain much energy. The insufficient energy does not excite electrons in molecules enough to be used for photosynthesis. Infrared light is converted to thermal energy instead 8. This angle will vary by latitude and season. The greater the angle of the sun, the more ozone that sunlight must pass through to reach the surface 9.

Cloud cover, air pollution and the hole in the ozone layer all alter the amount of solar radiation that can reach the surface. These factors all cause typical radiation levels to differ. The irradiance will increase from sunrise until noon, and then decrease until sunset Peak solar energy levels received will vary by latitude and season As seen on the graph to the left, the equator has the steepest solar radiation curve, giving it the shortest sunrise and sunset periods.

In addition, the length of day does not vary greatly throughout the year. This occurs because the angle of the sun does not significantly fluctuate over the equator. A hemisphere tilted toward the sun would reach a similar peak radiation level as the equator, but with more gradual curves, meaning longer sunrises and sunsets. This hemisphere would also have longer days overall. The opposing hemisphere tilted away from the sun would have shorter sunrises and sunsets, as well as shorter periods of daylight Although the daily values do not appear to change, the level of solar radiation received at the poles will slowly shift throughout the year.

Thus different areas of the globe have different typical radiation levels in each season. At the equator, the typical solar radiation is fairly constant year round There are slight fluctuations but no drastic spikes or drops. In the Northern Hemisphere, the radiation increases as the year progresses until it peaks around June or July. The radiation levels then slowly decrease throughout the rest of the year In the Southern Hemisphere, the radiation levels are opposite.

At the beginning of the year, levels are high and then slowly drop to their lowest point around June. After June, they begin to rise again for the rest of the year Ozone is a molecular gas composed of three oxygen atoms O 3. This area is not completely void of ozone, but is instead a patch of atmosphere that possesses a significantly lower level of ozone than normal While the cause of gap is sometimes a subject of debate, studies have shown that ozone is destroyed when it reacts with chlorine, nitrogen, hydrogen, or bromine When these chemicals enter the atmosphere, they can remove the ozone present.

Regardless of its cause, the hole in the ozone layer allows more UV radiation to reach Earth. If the increase in UV radiation becomes excessive, it can be harmful to both terrestrial and aqueous habitats Unusually high or low levels of sunlight can cause problems for both land and water habitats.

Too much ultraviolet light can cause irreversible damage to DNA and important photosynthetic structures, while too much infrared light can cause overheating 1. While most living cells have adapted and can repair simple damage, increased exposure to UV radiation can cause cells to mutate beyond repair, or to die On cloudy days, or if a previously sunny location becomes shaded, photosynthetic production can be halted. Not only does this stop oxygen production, but it increases oxygen consumption through plant respiration 1.

The decrease in infrared light will also cool the shaded surface or body of water, which in turns cools the surrounding air. When water is exposed to excessive amounts of sunlight, the infrared radiation will heat the water. The warmer a body water is, the faster the rate of evaporation will be. This can reduce water levels and water flow. In addition, warm water can not hold as much dissolved oxygen as cold water.

This means that in warmer water, less dissolved oxygen is available for aquatic organisms Too much infrared light can also cause the enzymes used in photosynthesis to denature, which can slow or halt the photosynthetic process On the other side of the spectrum, radiation can be limited by cloudy days, shade sources or low sun angles. If radiation from the sun is lower than usual for an extended period of time, photosynthetic production can decrease or be stopped completely.

Without sunlight, phytoplankton and plants will consume oxygen instead of producing it. These conditions can cause dissolved oxygen levels in the water to plummet, potentially causing a fish kill As in water, terrestrial radiation levels can be limited by cloudy weather Let's take a look at the various forms of light arriving from space, including the sunlight that blesses our planet.

Space is filled with waves of various wavelengths. In addition to visible light, there are wavelengths that cannot be seen by the naked eye, such as radio waves and infrared, ultraviolet, X-, and gamma rays.

These are collectively known as electromagnetic waves because they pass through space by alternately oscillating between electric and magnetic fields. Light is a type of electromagnetic wave. The electromagnetic waves reaching us consist of only a portion of the visible light, near-infrared rays and radio waves from space because the earth is surrounded by a layer of gases known as the atmosphere.

This structure is intimately related to the existence of life on earth. Life on earth receives the blessings of the light emitted by the sun. The energy that reaches the earth from the sun is about 2 calories per square centimeter per minute, the figure known as solar constant. Calculations based on this figure indicate that every second the sun emits as much energy into space as burning 10 quadrillion 10, trillion tons of coal.

The greatest of the sun's gifts to earth is photosynthesis by plants. When a material absorbs the energy of light, the light is changed into heat, thereby raising the object's temperature.

There are also cases where fluorescence or phosphorescence is emitted, but most of the time materials do not change. Sometimes, however, materials do chemically react to light. This is called a "photochemical reaction. Photosynthesis also is a type of chemical reaction. Plants use the energy of sunlight to synthesize glucose from carbon dioxide and water. They then use this glucose to produce such materials as starch and cellulose.

In short, photosynthesis stores the energy of sunlight in the form of glucose. All animals, including humans, live by eating these plants, thereby absorbing the oxygen produced during photosynthesis and indirectly taking in the energy of sunlight. In other words, sunlight is a source of life on earth.

We do not yet know the detail of how plants conduct photosynthesis, but in green plants, chloroplasts within cells are known to play a crucial role.

The earth is surrounded by layers of gases called the atmosphere. Some wavelengths of electromagnetic waves arriving from space are absorbed by the atmosphere and never reach the surface of our planet.

Take a look at the following diagram. The earth's atmosphere absorbs the majority of ultraviolet, X-, and gamma rays, which are all shorter wavelengths than visible light. Some of this energy is emitted back from the Earth's surface in the form of infrared radiation. Water vapor, carbon dioxide, methane, and other trace gases in Earth's atmosphere absorb the longer wavelengths of outgoing infrared radiation from Earth's surface.

These gases then emit the infrared radiation in all directions, both outward toward space and downward toward Earth. This process creates a second source of radiation to warm to surface — visible radiation from the sun and infrared radiation from the atmosphere — which causes Earth to be warmer than it otherwise would be. Some of this energy is emitted from Earth's surface back into space in the form of infrared radiation. Much of this infrared radiation does not reach space, however, because it is absorbed by greenhouse gases in atmosphere, and is then emitted as infrared radiation back toward the Earth's surface.

This process is known as the greenhouse effect. If the concentration of greenhouse gases increases, then more infrared radiation will be absorbed and emitted back toward Earth's surface, creating an enhanced or amplified greenhouse effect. When averaged over the course of a year, the amount of incoming solar radiation received from the sun has balanced the amount of outgoing energy emitted from Earth.

This equilibrium is called Earth's energy or radiation balance. Relatively small changes in the amounts of greenhouse gases in Earth's atmosphere can greatly alter that balance between incoming and outgoing radiation.

Earth then warms or cools in order to restore the radiative balance at the top of the atmosphere. Skip to Main Content Area. Home About Resources References. Energy: The Driver of Climate. The Greenhouse Effect Joseph Fourier. Image Credit: New World Encyclopedia. Image Credit: Microsoft Clip Art. Greenhouse Gases.

John Tyndall. Greenhouse Gas Absorption Spectrum.