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Diathermancy
Diathermancy (from "dia" ''through'' and "thermē" ''heat'') is the property of some fluids that allows rays of light through them without itself being heated. A wikt:diathermanous, diathermanous substance is thus "permeation, permeable" by heat. Diathermancy was first described by German physicist and chemist Heinrich Gustav Magnus in the 1800s.Magnus wrote initially four papers on Diathermanc/ref> Air ''is'' diathermanous; therefore atmospheric air ''is not'' heated by sunshine. Atmospheric air is heated by long-wave thermal radiation emitted by soil, and especially, by water on the Earth's surface. Water ''is not'' diathermanous, and it ''is'' heated directly by sunshine. Atmospheric heating from oceanic waters Atmospheric heat comes from long-wave radiation from the soil and, mostly, from the water surface (oceans, lakes, rivers), because water is a not diathermanous body and covers three quarters of Earth's surface. Diathermancy cause subsidence (atmosphere), subsidence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Gustav Magnus
Heinrich Gustav Magnus (; 2 May 1802 – 4 April 1870) was a notable German experimental scientist. His training was mostly in chemistry but his later research was mostly in physics. He spent the great bulk of his career at the University of Berlin, where he is remembered for his laboratory teaching as much as for his original research. He did not use his first given name, and was known throughout his life as Gustav Magnus. Education Magnus was born in Berlin to a Jewish family, his father a wealthy merchant. In his youth he received private instruction in mathematics and natural science. At the University of Berlin he studied chemistry and physics, 1822–27, and obtained a doctorate for a dissertation on tellurium in 1827. His doctoral adviser was Eilhard Mitscherlich. He then went to Stockholm for a year as a visiting research fellow at the laboratory of Jöns Jakob Berzelius (who was a personal friend of Mitscherlich). That was followed by a year in Paris at the laboratory of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunshine
Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when the Sun is above the horizon. When direct solar radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light and radiant heat. When blocked by clouds or reflected off other objects, sunlight is diffused. Sources estimate a global average of between 164 watts to 340 watts per square meter over a 24-hour day; this figure is estimated by NASA to be about a quarter of Earth's average total solar irradiance. The ultraviolet radiation in sunlight has both positive and negative health effects, as it is both a requisite for vitamin D3 synthesis and a mutagen. Sunlight takes about 8.3 minutes to reach Earth from the surface of the Sun. A photon starting at the center of the Sun and changing direction every ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subsidence (atmosphere)
In the meteorology, study of Earth's atmosphere, subsidence is the downward movement of an air parcel as it cools and becomes density, denser. By contrast, warm air becomes less dense and moves upwards (atmospheric convection). Subsidence generally creates a high-pressure area as more air moves into the same space: the polar highs are areas of almost constant subsidence, as are the horse latitudes, and the areas of subsidence are the sources of much of the world's prevailing winds. Subsidence also causes many smaller-scale weather phenomena, such as morning fog. An extreme form of subsidence is a downburst, which can result in damage similar to that produced by a tornado. A milder form of subsidence is referred to as downdraft. Atmospheric pressure and atmospheric subsidence The Dosen barometer (pictured) clearly relates high pressure with fine weather, as seen in its dial. This is because high pressure zones are subsidence zones, with dry and cool air descending and, theref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permeation
In physics and engineering, permeation (also called imbuing) is the penetration of a permeate (a fluid such as a liquid, gas, or vapor) through a solid. It is directly related to the concentration gradient of the permeate, a material's intrinsic permeability, and the materials' mass diffusivity. Permeation is modeled by equations such as Fick's laws of diffusion, and can be measured using tools such as a minipermeameter. Description The process of permeation involves the diffusion of molecules, called the permeant, through a membrane or interface. Permeation works through diffusion; the permeant will move from high concentration to low concentration across the interface. A material can be semipermeable, with the presence of a semipermeable membrane. Only molecules or ions with certain properties will be able to diffuse across such a membrane. This is a very important mechanism in biology where fluids inside a blood vessel need to be regulated and controlled. Permeation can occ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Radiation
Thermal radiation is electromagnetic radiation generated by the thermal motion of particles in matter. Thermal radiation is generated when heat from the movement of charges in the material (electrons and protons in common forms of matter) is converted to electromagnetic radiation. All matter with a temperature greater than absolute zero emits thermal radiation. At room temperature, most of the emission is in the infrared (IR) spectrum. Particle motion results in charge-acceleration or dipole oscillation which produces electromagnetic radiation. Infrared radiation emitted by animals (detectable with an infrared camera) and cosmic microwave background radiation are examples of thermal radiation. If a radiation object meets the physical characteristics of a black body in thermodynamic equilibrium, the radiation is called blackbody radiation. Planck's law describes the spectrum of blackbody radiation, which depends solely on the object's temperature. Wien's displacement law de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convection
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convection is unspecified, convection due to the effects of thermal expansion and buoyancy can be assumed. Convection may also take place in soft solids or mixtures where particles can flow. Convective flow may be transient (such as when a multiphase mixture of oil and water separates) or steady state (see Convection cell). The convection may be due to gravitational, electromagnetic or fictitious body forces. Heat transfer by natural convection plays a role in the structure of Earth's atmosphere, its oceans, and its mantle. Discrete convective cells in the atmosphere can be identified by clouds, with stronger convection resulting in thunderstorms. Natural convection also plays a role in stellar physics. Convection is often categorised or d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenhouse Effect
The greenhouse effect is a process that occurs when energy from a planet's host star goes through the planet's atmosphere and heats the planet's surface, but greenhouse gases in the atmosphere prevent some of the heat from returning directly to space, resulting in a warmer planet. Earth's natural greenhouse effect makes life as we know it possible and carbon dioxide plays a significant role in providing for the relatively high temperature on Earth. The greenhouse effect is a process by which thermal radiation from a planetary atmosphere warms the planet's surface beyond the temperature it would have in the absence of its atmosphere.A concise description of the greenhouse effect is given in the ''Intergovernmental Panel on Climate Change Fourth Assessment Report,'' "What is the Greenhouse Effect?FAQ 1.3 – AR4 WGI Chapter 1: Historical Overview of Climate Change Science, IPCC Fourth Assessment Report, Chapter 1, p. 115: "To balance the absorbed incoming olarenergy, the Earth m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outgoing Longwave Radiation
Outgoing Long-wave Radiation (OLR) is electromagnetic radiation of wavelengths from 3–100 μm emitted from Earth and its atmosphere out to space in the form of thermal radiation. It is also referred to as up-welling long-wave radiation and terrestrial long-wave flux, among others. The flux of energy transported by outgoing long-wave radiation is measured in W/m2. In the Earth's climate system, long-wave radiation involves processes of absorption, scattering, and emissions from atmospheric gases, aerosols, clouds and the surface. Over 99% of outgoing long-wave radiation has wavelengths between 4 μm and 100 μm, in the thermal infrared part of the electromagnetic spectrum. Contributions with wavelengths larger than 40 μm are small, therefore often only wavelengths up to 50 μm are considered . In the wavelength range between 4 μm and 10 μm the spectrum of outgoing long-wave radiation overlaps that of solar radiation, and for various applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
