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55-437: With an elevation of around 4,200 metres (14,000 ft), Qumarlêb County has an alpine climate ( Köppen ETH ), with long, very cold winters, and short, cool and rainy summers. Average low temperatures are below freezing from mid September to late May; however, due to the wide diurnal temperature variation , average highs are only below freezing from mid/late November until early March. Despite frequent rain during summer, when

110-596: A majority of days sees rain, no month has less than 50 percent of possible sunshine; with monthly percent possible sunshine ranging from 51 percent in June to 78 percent in November, the county seat receives 2,782 hours of bright sunshine annually. The monthly 24-hour average temperature ranges from −14.5 °C (5.9 °F) in January to 8.9 °C (48.0 °F) in July, while the annual mean

165-491: A mountain is roughly equivalent to moving 80 kilometres (50 miles or 0.75° of latitude ) towards the pole. This relationship is only approximate, however, since local factors, such as proximity to oceans , can drastically modify the climate. As the altitude increases, the main form of precipitation becomes snow and the winds increase. The temperature continues to drop until the tropopause , at 11,000 metres (36,000 ft), where it does not decrease further. This

220-582: A planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Surface heating can happen from an internal heat source as in the case of Jupiter , or from its host star as in the case of the Earth . In the case of Earth, the Sun emits shortwave radiation ( sunlight ) that passes through greenhouse gases to heat the Earth's surface. In response, the Earth's surface emits longwave radiation that

275-410: A rate that is directly proportional to the fourth power of its temperature . Some of the radiation emitted by the Earth's surface is absorbed by greenhouse gases and clouds. Without this absorption, Earth's surface would have an average temperature of −18 °C (−0.4 °F). However, because some of the radiation is absorbed, Earth's average surface temperature is around 15 °C (59 °F). Thus,

330-434: A state of radiative equilibrium , in which the power of outgoing radiation equals the power of absorbed incoming radiation. Earth's energy imbalance is the amount by which the power of incoming sunlight absorbed by Earth's surface or atmosphere exceeds the power of outgoing longwave radiation emitted to space. Energy imbalance is the fundamental measurement that drives surface temperature. A UN presentation says "The EEI

385-448: A surface temperature of 5,500 °C (9,900 °F), so it emits most of its energy as shortwave radiation in near-infrared and visible wavelengths (as sunlight). In contrast, Earth's surface has a much lower temperature, so it emits longwave radiation at mid- and far- infrared wavelengths. A gas is a greenhouse gas if it absorbs longwave radiation . Earth's atmosphere absorbs only 23% of incoming shortwave radiation, but absorbs 90% of

440-478: Is an associated effective emission temperature (or brightness temperature ). A given wavelength of radiation may also be said to have an effective emission altitude , which is a weighted average of the altitudes within the radiating layer. The effective emission temperature and altitude vary by wavelength (or frequency). This phenomenon may be seen by examining plots of radiation emitted to space. Earth's surface radiates longwave radiation with wavelengths in

495-440: Is because their molecules are symmetrical and so do not have a dipole moment.) Such gases make up more than 99% of the dry atmosphere. Greenhouse gases absorb and emit longwave radiation within specific ranges of wavelengths (organized as spectral lines or bands ). When greenhouse gases absorb radiation, they distribute the acquired energy to the surrounding air as thermal energy (i.e., kinetic energy of gas molecules). Energy

550-465: Is because when these molecules vibrate , those vibrations modify the molecular dipole moment , or asymmetry in the distribution of electrical charge. See Infrared spectroscopy .) Gases with only one atom (such as argon, Ar) or with two identical atoms (such as nitrogen, N 2 , and oxygen, O 2 ) are not infrared active. They are transparent to longwave radiation, and, for practical purposes, do not absorb or emit longwave radiation. (This

605-454: Is being measured. Strengthening of the greenhouse effect through additional greenhouse gases from human activities is known as the enhanced greenhouse effect . As well as being inferred from measurements by ARGO , CERES and other instruments throughout the 21st century, this increase in radiative forcing from human activity has been observed directly, and is attributable mainly to increased atmospheric carbon dioxide levels. CO 2

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660-435: Is essential to the greenhouse effect. If the lapse rate was zero (so that the atmospheric temperature did not vary with altitude and was the same as the surface temperature) then there would be no greenhouse effect (i.e., its value would be zero). Greenhouse gases make the atmosphere near Earth's surface mostly opaque to longwave radiation. The atmosphere only becomes transparent to longwave radiation at higher altitudes, where

715-422: Is expressed in units of W/m , which is the number of joules of energy that pass through a square meter each second. Most fluxes quoted in high-level discussions of climate are global values, which means they are the total flow of energy over the entire globe, divided by the surface area of the Earth, 5.1 × 10  m (5.1 × 10  km ; 2.0 × 10  sq mi). The fluxes of radiation arriving at and leaving

770-979: Is higher than the highest summit . Although this climate classification only covers a small portion of the Earth's surface, alpine climates are widely distributed. They are present in the Himalayas , the Tibetan Plateau , Gansu , Qinghai and Mount Lebanon in Asia ; the Alps , the Urals , the Pyrenees , the Cantabrian Mountains and the Sierra Nevada in Europe ; the Andes in South America ;

825-453: Is known as the adiabatic lapse rate , which is approximately 9.8 °C per kilometer (or 5.4 °F per 1000 feet) of altitude. The presence of water in the atmosphere complicates the process of convection. Water vapor contains latent heat of vaporization . As air rises and cools, it eventually becomes saturated and cannot hold its quantity of water vapor. The water vapor condenses (forming clouds ), and releases heat, which changes

880-517: Is mostly absorbed by greenhouse gases. The absorption of longwave radiation prevents it from reaching space, reducing the rate at which the Earth can cool off. Without the greenhouse effect, the Earth's average surface temperature would be as cold as −18 °C (−0.4 °F). This is of course much less than the 20th century average of about 14 °C (57 °F). In addition to naturally present greenhouse gases, burning of fossil fuels has increased amounts of carbon dioxide and methane in

935-482: Is produced by fossil fuel burning and other activities such as cement production and tropical deforestation . Measurements of CO 2 from the Mauna Loa Observatory show that concentrations have increased from about 313 parts per million (ppm) in 1960, passing the 400 ppm milestone in 2013. The current observed amount of CO 2 exceeds the geological record maxima (≈300 ppm) from ice core data. Over

990-445: Is sometimes called thermal radiation . Outgoing longwave radiation (OLR) is the radiation from Earth and its atmosphere that passes through the atmosphere and into space. The greenhouse effect can be directly seen in graphs of Earth's outgoing longwave radiation as a function of frequency (or wavelength). The area between the curve for longwave radiation emitted by Earth's surface and the curve for outgoing longwave radiation indicates

1045-424: Is the most critical number defining the prospects for continued global warming and climate change." One study argues, "The absolute value of EEI represents the most fundamental metric defining the status of global climate change." Earth's energy imbalance (EEI) was about 0.7 W/m as of around 2015, indicating that Earth as a whole is accumulating thermal energy and is in a process of becoming warmer. Over 90% of

1100-444: Is the process of convection . Convection comes to equilibrium when a parcel of air at a given altitude has the same density as its surroundings. Air is a poor conductor of heat, so a parcel of air will rise and fall without exchanging heat. This is known as an adiabatic process , which has a characteristic pressure-temperature curve. As the pressure gets lower, the temperature decreases. The rate of decrease of temperature with elevation

1155-503: Is the typical climate for elevations above the tree line , where trees fail to grow due to cold. This climate is also referred to as a mountain climate or highland climate . There are multiple definitions of alpine climate. In the Köppen climate classification , the alpine and mountain climates are part of group E , along with the polar climate , where no month has a mean temperature higher than 10 °C (50 °F). According to

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1210-404: Is transferred from greenhouse gas molecules to other molecules via molecular collisions . Contrary to what is sometimes said, greenhouse gases do not "re-emit" photons after they are absorbed. Because each molecule experiences billions of collisions per second, any energy a greenhouse gas molecule receives by absorbing a photon will be redistributed to other molecules before there is a chance for

1265-403: Is −2.13 °C (28.2 °F). Over three-fourths of the annual precipitation of 406 mm (16.0 in) is delivered from June to September. In recent years, affected by global warming , the rate of temperature increase has increased significantly in the past 10 years. In August 2022 , the hottest month in history was recorded, with an average temperature of 13.9 °C (57.0 °F), and

1320-567: The Holdridge life zone system, there are two mountain climates which prevent tree growth : a) the alpine climate, which occurs when the mean biotemperature of a location is between 1.5 and 3 °C (34.7 and 37.4 °F). The alpine climate in Holdridge system is roughly equivalent to the warmest tundra climates (ET) in the Köppen system. b) the alvar climate, the coldest mountain climate since

1375-937: The Sierra Nevada , the Cascade Range , the Rocky Mountains , the northern Appalachian Mountains ( Adirondacks and White Mountains ), and the Trans-Mexican Volcanic Belt in North America ; the Southern Alps in New Zealand ; the Snowy Mountains in Australia ; high elevations in the Atlas Mountains , Ethiopian Highlands , and Eastern Highlands of Africa ; the central parts of Borneo and New Guinea ; and

1430-407: The thermal inertia of the climate system resists changes both day and night, as well as for longer periods. Diurnal temperature changes decrease with height in the atmosphere. In the lower portion of the atmosphere, the troposphere , the air temperature decreases (or "lapses") with increasing altitude. The rate at which temperature changes with altitude is called the lapse rate . On Earth,

1485-559: The Earth and its atmosphere emit longwave radiation . Sunlight includes ultraviolet , visible light , and near-infrared radiation. Sunlight is reflected and absorbed by the Earth and its atmosphere. The atmosphere and clouds reflect about 23% and absorb 23%. The surface reflects 7% and absorbs 48%. Overall, Earth reflects about 30% of the incoming sunlight, and absorbs the rest (240 W/m ). The Earth and its atmosphere emit longwave radiation , also known as thermal infrared or terrestrial radiation . Informally, longwave radiation

1540-420: The Earth are important because radiative transfer is the only process capable of exchanging energy between Earth and the rest of the universe. The temperature of a planet depends on the balance between incoming radiation and outgoing radiation. If incoming radiation exceeds outgoing radiation, a planet will warm. If outgoing radiation exceeds incoming radiation, a planet will cool. A planet will tend towards

1595-400: The Earth's greenhouse effect can also be measured as an energy flow change of 159 W/m . The greenhouse effect can be expressed as a fraction (0.40) or percentage (40%) of the longwave thermal radiation that leaves Earth's surface but does not reach space. Whether the greenhouse effect is expressed as a change in temperature or as a change in longwave thermal radiation, the same effect

1650-481: The Earth's greenhouse effect may be measured as a temperature change of 33 °C (59 °F). Thermal radiation is characterized by how much energy it carries, typically in watts per square meter (W/m ). Scientists also measure the greenhouse effect based on how much more longwave thermal radiation leaves the Earth's surface than reaches space. Currently, longwave radiation leaves the surface at an average rate of 398 W/m , but only 239 W/m reaches space. Thus,

1705-471: The air is less dense, there is less water vapor, and reduced pressure broadening of absorption lines limits the wavelengths that gas molecules can absorb. For any given wavelength, the longwave radiation that reaches space is emitted by a particular radiating layer of the atmosphere. The intensity of the emitted radiation is determined by the weighted average air temperature within that layer. So, for any given wavelength of radiation emitted to space, there

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1760-416: The air temperature decreases by about 6.5 °C/km (3.6 °F per 1000 ft), on average, although this varies. The temperature lapse is caused by convection . Air warmed by the surface rises. As it rises, air expands and cools . Simultaneously, other air descends, compresses, and warms. This process creates a vertical temperature gradient within the atmosphere. This vertical temperature gradient

1815-410: The amount of longwave radiation emitted by the surface: Earth's surface temperature is often reported in terms of the average near-surface air temperature. This is about 15 °C (59 °F), a bit lower than the effective surface temperature. This value is 33 °C (59 °F) warmer than Earth's overall effective temperature. Energy flux is the rate of energy flow per unit area. Energy flux

1870-448: The atmosphere with greenhouse gases absorbs some of the longwave radiation being radiated upwards from lower layers. It also emits longwave radiation in all directions, both upwards and downwards, in equilibrium with the amount it has absorbed. This results in less radiative heat loss and more warmth below. Increasing the concentration of the gases increases the amount of absorption and emission, and thereby causing more heat to be retained at

1925-500: The atmosphere, with the main gases having no effect, and was largely due to water vapor, though small percentages of hydrocarbons and carbon dioxide had a significant effect. The effect was more fully quantified by Svante Arrhenius in 1896, who made the first quantitative prediction of global warming due to a hypothetical doubling of atmospheric carbon dioxide. The term greenhouse was first applied to this phenomenon by Nils Gustaf Ekholm in 1901. Matter emits thermal radiation at

1980-532: The atmosphere. As a result, global warming of about 1.2 °C (2.2 °F) has occurred since the Industrial Revolution , with the global average surface temperature increasing at a rate of 0.18 °C (0.32 °F) per decade since 1981. All objects with a temperature above absolute zero emit thermal radiation . The wavelengths of thermal radiation emitted by the Sun and Earth differ because their surface temperatures are different. The Sun has

2035-492: The atmosphere." The enhanced greenhouse effect describes the fact that by increasing the concentration of GHGs in the atmosphere (due to human action), the natural greenhouse effect is increased. The term greenhouse effect comes from an analogy to greenhouses . Both greenhouses and the greenhouse effect work by retaining heat from sunlight, but the way they retain heat differs. Greenhouses retain heat mainly by blocking convection (the movement of air). In contrast,

2090-419: The biotemperature is between 0 °C and 1.5 °C (biotemperature can never be below 0 °C). It corresponds more or less to the coldest tundra climates and to the ice cap climates (EF) as well. Holdrige reasoned that plants net primary productivity ceases with plants becoming dormant at temperatures below 0 °C (32 °F) and above 30 °C (86 °F). Therefore, he defined biotemperature as

2145-410: The decreasing concentration of water vapor, an important greenhouse gas. Rather than thinking of longwave radiation headed to space as coming from the surface itself, it is more realistic to think of this outgoing radiation as being emitted by a layer in the mid- troposphere , which is effectively coupled to the surface by a lapse rate . The difference in temperature between these two locations explains

2200-689: The difference between surface emissions and emissions to space, i.e., it explains the greenhouse effect. A greenhouse gas (GHG) is a gas which contributes to the trapping of heat by impeding the flow of longwave radiation out of a planet's atmosphere. Greenhouse gases contribute most of the greenhouse effect in Earth's energy budget . Gases which can absorb and emit longwave radiation are said to be infrared active and act as greenhouse gases. Most gases whose molecules have two different atoms (such as carbon monoxide, CO ), and all gases with three or more atoms (including H 2 O and CO 2 ), are infrared active and act as greenhouse gases. (Technically, this

2255-466: The effect is even greater with carbon dioxide. The term greenhouse was first applied to this phenomenon by Nils Gustaf Ekholm in 1901. The greenhouse effect on Earth is defined as: "The infrared radiative effect of all infrared absorbing constituents in the atmosphere. Greenhouse gases (GHGs), clouds , and some aerosols absorb terrestrial radiation emitted by the Earth’s surface and elsewhere in

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2310-421: The greenhouse effect retains heat by restricting radiative transfer through the air and reducing the rate at which thermal radiation is emitted into space. The existence of the greenhouse effect, while not named as such, was proposed as early as 1824 by Joseph Fourier . The argument and the evidence were further strengthened by Claude Pouillet in 1827 and 1838. In 1856 Eunice Newton Foote demonstrated that

2365-401: The highest temperature ever recorded was 25.6 °C (78.1 °F) on the 9th of the month. Summer has also been affected, with a 21.1 °C (70.0 °F) average high for August 2016, and August 2022. Qumarlêb County is divided to 1 town and 5 townships. This Qinghai location article is a stub . You can help Misplaced Pages by expanding it . Alpine climate Alpine climate

2420-440: The lapse rate from the dry adiabatic lapse rate to the moist adiabatic lapse rate (5.5 °C per kilometre or 3 °F per 1000 feet). The actual lapse rate, called the environmental lapse rate , is not constant (it can fluctuate throughout the day or seasonally and also regionally), but a normal lapse rate is 5.5 °C per 1,000 m (3.57 °F per 1,000 ft). Therefore, moving up 100 metres (330 ft) on

2475-456: The longwave radiation emitted by the surface, thus accumulating energy and warming the Earth's surface. The existence of the greenhouse effect, while not named as such, was proposed as early as 1824 by Joseph Fourier . The argument and the evidence were further strengthened by Claude Pouillet in 1827 and 1838. In 1856 Eunice Newton Foote demonstrated that the warming effect of the sun is greater for air with water vapour than for dry air, and

2530-421: The mean of all temperatures but with all temperatures below freezing and above 30 °C adjusted to 0 °C; that is, the sum of temperatures not adjusted is divided by the number of all temperatures (including both adjusted and non-adjusted ones). The variability of the alpine climate throughout the year depends on the latitude of the location. For tropical oceanic locations, such as the summit of Mauna Loa ,

2585-427: The past 800,000 years, ice core data shows that carbon dioxide has varied from values as low as 180 ppm to the pre-industrial level of 270 ppm. Paleoclimatologists consider variations in carbon dioxide concentration to be a fundamental factor influencing climate variations over this time scale. Hotter matter emits shorter wavelengths of radiation. As a result, the Sun emits shortwave radiation as sunlight while

2640-422: The range of 4–100 microns. Greenhouse gases that were largely transparent to incoming solar radiation are more absorbent for some wavelengths in this range. The atmosphere near the Earth's surface is largely opaque to longwave radiation and most heat loss from the surface is by evaporation and convection . However radiative energy losses become increasingly important higher in the atmosphere, largely because of

2695-408: The retained energy goes into warming the oceans, with much smaller amounts going into heating the land, atmosphere, and ice. A simple picture assumes a steady state, but in the real world, the day/night ( diurnal ) cycle, as well as the seasonal cycle and weather disturbances, complicate matters. Solar heating applies only during daytime. At night the atmosphere cools somewhat, but not greatly because

2750-417: The size of the greenhouse effect. Different substances are responsible for reducing the radiation energy reaching space at different frequencies; for some frequencies, multiple substances play a role. Carbon dioxide is understood to be responsible for the dip in outgoing radiation (and associated rise in the greenhouse effect) at around 667 cm (equivalent to a wavelength of 15 microns). Each layer of

2805-655: The summits of Mount Pico in the Atlantic and Mauna Loa in the Pacific . The lowest altitude of alpine climate varies dramatically by latitude. If alpine climate is defined by the tree line, then it occurs as low as 650 metres (2,130 ft) at 68°N in Sweden, while on Mount Kilimanjaro in Tanzania, the tree line is at 3,950 metres (12,960 ft). Greenhouse effect The greenhouse effect occurs when greenhouse gases in

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2860-430: The surface and in the layers below. The power of outgoing longwave radiation emitted by a planet corresponds to the effective temperature of the planet. The effective temperature is the temperature that a planet radiating with a uniform temperature (a blackbody ) would need to have in order to radiate the same amount of energy. This concept may be used to compare the amount of longwave radiation emitted to space and

2915-403: The surface. If radiation were the only way to transfer heat from the ground to space, the greenhouse effect of gases in the atmosphere would keep the ground at roughly 333 K (60 °C; 140 °F), and the temperature would decay exponentially with height. However, when air is hot, it tends to expand, which lowers its density. Thus, hot air tends to rise and transfer heat upward. This

2970-460: The temperature is roughly constant throughout the year. For mid-latitude locations, such as Mount Washington in New Hampshire , the temperature varies seasonally, but never gets very warm. The temperature profile of the atmosphere is a result of an interaction between radiation and convection . Sunlight in the visible spectrum hits the ground and heats it. The ground then heats the air at

3025-422: The warming effect of the sun is greater for air with water vapour than for dry air, and the effect is even greater with carbon dioxide. She concluded that "An atmosphere of that gas would give to our earth a high temperature..." John Tyndall was the first to measure the infrared absorption and emission of various gases and vapors. From 1859 onwards, he showed that the effect was due to a very small proportion of

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