Long wave radiation from the sun passes through greenhouse gases. The surface of the earth emits long wave radiation that is absorbed by greenhouse gases. They re-emit the energy as long wave radiation in all directions. Water vapor, on the other hand, is an insulating gas. It absorbs heat and radiates it back out into space.
This is the reason why the air is so cold in winter and so warm in summer. Earth is at its warmest, it is surrounded by a thin layer of water vapour. As the temperature of this layer increases, so does the amount of heat that can be trapped by it.
At the same time, as the water evaporates, more and more heat is lost to space as infrared radiation. The result is that the planet warms and cools over the course of a year, depending on how much water is evaporating and how quickly the greenhouse effect is taking place.
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What do greenhouse gases do to shortwave radiation?
The greenhouse effect has been around for a long time. Increased concentrations of greenhouse gases, such as CO2, reduce the amount of outgoing longwave radiation (OLR) to space; thus, energy accumulates in the climate system, and the temperature of the Earth’s surface increases.
For example, in a study published in Nature Climate Change, researchers from the University of East Anglia (UEA) in Norwich, UK, found that the effect of increased greenhouse gas concentrations on global surface temperatures has been overestimated by up to a factor of 10. The researchers used a model to simulate the effects of a doubling of atmospheric carbon dioxide (CO2) concentration on the global mean surface temperature over the 21st century.
Their results showed that, on average, the observed increase in global temperature is likely to be between 0.5 and 1.0 degrees Celsius, rather than the 2-3 degrees predicted by climate models.
This finding is consistent with the results of other studies, which have shown that global warming may be less than 1 degree Celsius per decade, according to the Intergovernmental Panel on Climate change (IPCC), the United Nations body that assesses the science of climate change.
What type of radiation does a greenhouse gas absorb?
Greenhouse gases are responsible for the warming of the planet’s surface. In addition to carbon dioxide, methane, nitrous oxide and water vapor are also known to be greenhouse gasses. In fact, all of these gases contribute to the greenhouse effect, but methane is the most potent greenhouse gas.
Do greenhouse gases reflect thermal energy shortwave radiation?
The heat from Earth’s surface is re-radiated from high clouds. The incoming sunlight is reflected back into space by low clouds. As a result, the amount of heat absorbed by a cloud is directly proportional to the temperature of the surrounding air. The higher the cloud’s albedo (reflectivity), the more heat is absorbed and the lower its temperature will be.
This is why clouds are often referred to as “thermometers” or “indicators of climate change” because they can be used to measure changes in temperature. In the case of clouds, however, it is important to note that they do not reflect all incoming solar radiation back to space, but only a portion of it.
For example, clouds can absorb up to 90% of incoming shortwave (infrared) radiation, while the remaining 10% is reflected by the ground. Thus, cloud cover is not a perfect indicator of global warming, because it does not take into account the fact that clouds absorb a small fraction of solar energy, and that some of that energy is lost as heat.
Do greenhouse gases transmit shortwave or longwave radiation?
This is called the greenhouse effect, and it is a major contributor to global warming. Greenhouse gas concentrations are measured in parts per million (ppm). CO2 is the most common greenhouse gas, but other gases, such as methane and nitrous oxide, also contribute to warming the planet. The higher a concentration is of a particular greenhouse gaseous gas (e.g., methane), the greater the warming effect.
Does methane absorb shortwave radiation?
The new study, published in the journal Geophysical Research Letters, found that the warming effect of methane on the surface of the planet is much larger than previously thought. The study also shows that methane is a much more potent greenhouse gas than carbon dioxide, which has been widely assumed to be the primary driver of global warming.
What is the difference between shortwave and longwave radiation?
The amount of radiation absorbed by the human body is directly proportional to the wavelength of the radiation. For example, if you are standing in a room with a white wall and a black wall, you will absorb more radiation from the white walls than the black walls.
This is because white light is absorbed more easily than black light. The same is true for radio waves, microwaves, X-rays, ultraviolet light, visible light and other forms of electromagnetic radiation, which are all absorbed differently by different types of cells in the body.
What wavelength does CO2 absorb?
The range in which carbon dioxide absorbs energy is between 2,000 and 15,000 nanometers, which is the same as the range in which infrared energy is absorbed. CO2 soaks up the infrared energy, it vibrates and re-emits it in the form of visible light. In the new study, the researchers used a technique called fluorescence spectroscopy to measure the absorption of light by carbon dioxide molecules.
The researchers found that the amount of energy absorbed by a molecule depends on the wavelength of the light it absorbs. In other words, light from a blue light bulb absorbs more energy when it is absorbed at longer wavelengths than when the same light is emitted at shorter wavelengths.
Does CO2 absorb longwave radiation?
The greenhouse gas and water vapor absorb the radiation from different parts of the spectrum. The researchers found that the greenhouse effect is strongest in the infrared region, which is dominated by methane and carbon dioxide. The researchers that this is because methane is a more efficient greenhouse than other gases, such as water vapour, because it absorbs more energy than water does.
