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Global Dimming
Global dimming is the reduction in the amount of global direct irradiance at the Earth's surface that has been observed since systematic measurements began in the 1950s. The effect varies by location, but worldwide it has been estimated to be of the order of a 4–20% reduction. However, after discounting an anomaly caused by the eruption of Mount Pinatubo in 1991, a very slight reversal in the overall trend has been observed. Global dimming is thought to have been caused by an increase in particulates or aerosols, such as sulfate aerosols in the atmosphere due to human action. It has interfered with the hydrological cycle by reducing evaporation and may have reduced rainfall in some areas. Global dimming has been attributed as the leading factor in the 1984 Ethiopian famine by reducing heating at the tropics which drives the annual monsoon, or wet season. Causes It is thought that global dimming is probably due to the increased presence of aerosol particles in Earth's atmosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollution Over East China
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Although environmental pollution can be caused by natural events, the word pollution generally implies that the contaminants have an anthropogenic source – that is, a source created by human activities. Pollution is often classed as point source or nonpoint source pollution. In 2015, pollution killed nine million people worldwide (one in six deaths). This remained unchanged in 2019, with little real progress against pollution being identifiable. Air pollution accounted for of these earlier deaths. Major forms of pollution include air pollution, light pollution, litter, noise pollution, plastic pollution, soil contamination, radioacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Eruptions
Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions: * Magmatic eruptions are the most well-observed type of eruption. They involve the decompression of gas within magma that propels it forward. * Phreatic eruptions are driven by the superheating of steam due to the close proximity of magma. This type exhibits no magmatic release, instead causing the granulation of existing rock. * Phreatomagmatic eruptions are driven by the direct interaction of magma and water, as opposed to phreatic eruptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asian Brown Cloud
The Indian Ocean brown cloud or Asian brown cloud is a layer of air pollution that recurrently covers parts of South Asia, namely the northern Indian Ocean, India, and Pakistan. Viewed from satellite photos, the cloud appears as a giant brown stain hanging in the air over much of South Asia and the Indian Ocean every year between January and March, possibly also during earlier and later months. The term was coined in reports from the UNEP Indian Ocean Experiment (INDOEX). It was found to originate mostly due to Sikh farmers burning stubble in Punjab and to lesser extent Haryana. The debilitating air quality in Delhi is also due to the stubble burning in Punjab.Ramanathan, Veerabhadran ''et al.'' (2002''The Asian brown cloud climate and other environmental impacts: impact study'' Center for Clouds, Chemistry and Climate, United Nations Environment Programme, Nairobi Kenya, , accessed 8 December 2008 The term ''atmospheric brown cloud'' is used for a more generic context not speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the north; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives; its Andaman and Nicobar Islands share a maritime border with Thailand, Myanmar, and Indonesia. Modern humans arrived on the Indian subcontinent from Africa no later than 55,000 years ago., "Y-Chromosome and Mt-DNA data support the colonization of South Asia by modern humans originating in Africa. ... Coalescence dates for most non-European populations average to betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maldives
Maldives (, ; dv, ދިވެހިރާއްޖެ, translit=Dhivehi Raajje, ), officially the Republic of Maldives ( dv, ދިވެހިރާއްޖޭގެ ޖުމްހޫރިއްޔާ, translit=Dhivehi Raajjeyge Jumhooriyyaa, label=none, ), is an archipelagic state located in South Asia, situated in the Indian Ocean. It lies southwest of Sri Lanka and India, about from the Asian continent's mainland. The chain of atolls of the Maldives, 26 atolls stretches across the equator from Atolls of the Maldives#Ihavandhippolhu, Ihavandhippolhu Atoll in the north to Addu Atoll in the south. Comprising a territory spanning roughly including the sea, land area of all the islands comprises , Maldives is one of the world's most geographically dispersed sovereign states and the List of sovereign states and dependent territories in Asia, smallest Asian country as well as one of the smallest Muslim countries, Muslim-majority countries by land area and, with around 557,751 inhabitants, the 2nd List of Asian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Daily
''Science Daily'' is an American website launched in 1995 that aggregates press releases and publishes lightly edited press releases (a practice called churnalism) about science, similar to Phys.org and EurekAlert!. The site was founded by married couple Dan and Michele Hogan in 1995; Dan Hogan formerly worked in the public affairs department of Jackson Laboratory writing press releases. The site makes money from selling advertisements. As of 2010, the site said that it had grown "from a two-person operation to a full-fledged news business with worldwide contributors". At the time, it was run out of the Hogans' home, had no reporters, and only reprinted press releases. In 2012, Quantcast ranked it at 614 with 2.6 million U.S. visitors. References External links * Alexa - ScienceDaily News aggregators Internet properties established in 1995 American science websites {{sci-mag-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soot
Soot ( ) is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke that may become airborne during pyrolysis and that are more properly identified as cokes or char. Soot causes various types of cancer and lung disease. Sources Soot as an airborne contaminant in the environment has many different sources, all of which are results of some form of pyrolysis. They include soot from coal burning, internal-combustion engines, power-plant boilers, hog-fuel boilers, ship boilers, central steam-heat boilers, waste incineration, local field burning, house fires, forest fires, fireplaces, and furnaces. These exterior sources also contribute to the indoor environment sources such as smoking of plant matter, cooking, oil lamps, candles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Carbon
Chemically, black carbon (BC) is a component of fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter). Black carbon consists of pure carbon in several linked forms. It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass, and is one of the main types of particle in both anthropogenic and naturally occurring soot. Black carbon causes human morbidity and premature mortality. Because of these human health impacts, many countries have worked to reduce their emissions, making it an easy pollutant to abate in anthropogenic sources. In climatology, black carbon is a climate forcing agent contributing to global warming. Black carbon warms the Earth by absorbing sunlight and heating the atmosphere and by reducing albedo when deposited on snow and ice (direct effects) and indirectly by interaction with clouds, with the total forcing of 1.1 W/m2. Black carbon stays in the atmosphere for only several days to weeks, whereas potent greenhouse gas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diesel Fuel
Diesel fuel , also called diesel oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics. The most common type of diesel fuel is a specific fractional distillate of petroleum fuel oil, but alternatives that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel are increasingly being developed and adopted. To distinguish these types, petroleum-derived diesel is sometimes called petrodiesel in some academic circles. In many countries, diesel fuel is standardised. For example, in the European Union, the standard for diesel fuel is EN 590. Diesel fuel has many colloquial names; most commonly, it is simply referred to as ''diesel''. In the United Kingdom, diesel fuel for on-road use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Northwest National Laboratory
Pacific Northwest National Laboratory (PNNL) is one of the United States Department of Energy national laboratories, managed by the Department of Energy's (DOE) Office of Science. The main campus of the laboratory is in Richland, Washington. Originally named the Pacific Northwest Laboratory, PNL was established in 1965 when research and development at the Hanford Site was separated from other Hanford operations. In 1995, the laboratory was renamed the Pacific Northwest National Laboratory also known as PNNL. Facilities PNNL houses several scientific user facilities and research facilities. Scientific user facilities The Environmental Molecular Sciences Laboratory (EMSL) is a U.S. Department of Energy national scientific user facility. EMSL provides researchers around the world with integrated capabilities in oxide and mineral interface chemistry, high-performance computing and computational chemistry software, mass spectrometry, high-field magnetic resonance, and sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albedo
Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that reflects all incident radiation. Surface albedo is defined as the ratio of radiosity ''J''e to the irradiance ''E''e (flux per unit area) received by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface. These factors vary with atmospheric composition, geographic location, and time (see position of the Sun). While bi-hemispherical reflectance is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as obtained from flux measurements) t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coalescence (physics)
Coalescence is the process by which two or more droplets, bubbles or particles merge during contact to form a single daughter droplet, bubble or particle. It can take place in many processes, ranging from meteorology to astrophysics. For example, it is seen in the formation of raindrops as well as planetary and star formation. In meteorology, its role is crucial in the formation of rain. As droplets are carried by the updrafts and downdrafts in a cloud, they collide and coalesce to form larger droplets. When the droplets become too large to be sustained on the air currents, they begin to fall as rain. Adding to this process, the cloud may be seeded with ice from higher altitudes, either via the cloud tops reaching , or via the cloud being seeded by ice from cirrus clouds. Contrast-enhanced ultrasound in medicine applies microscopic bubbles for imaging and therapy. Coalescence of ultrasound contrast agent microbubbles is studied to prevent embolies or to block tumour vess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
