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Lester Machta
Lester Machta (February 17, 1919 – August 31, 2001) was an American meteorologist, the first director of the Air Resources Laboratory (ARL) of the National Oceanic and Atmospheric Administration. Life Lester Machta was born in Brooklyn, New York, the son of Jewish immigrants from Russia. He attended City College and Brooklyn College, graduating in 1939. After a year of graduate study Machta entered military service as a meteorology instructor training pilots for the Army and Army Air Corps. He received an M.A. in meteorology from New York University in 1946 and a Sc.D. in meteorology from M.I.T. in 1948. He married Phyllis Margaretten in 1948; they had two children. Career In 1948 Harry Wexler hired Machta to join the United States Weather Bureau as Chief of the Special Projects Section, which later became the Air Resources Laboratory. The Special Projects Section was created to study the atmospheric effects of nuclear weapons tests. Even before the Soviet Union develope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brooklyn
Brooklyn () is a borough of New York City, coextensive with Kings County, in the U.S. state of New York. Kings County is the most populous county in the State of New York, and the second-most densely populated county in the United States, behind New York County (Manhattan). Brooklyn is also New York City's most populous borough,2010 Gazetteer for New York State . Retrieved September 18, 2016. with 2,736,074 residents in 2020. Named after the Dutch village of Breukelen, Brooklyn is located on the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Testing At Bikini Atoll
Nuclear testing at Bikini Atoll consisted of the detonation of 23 nuclear weapons by the United States between 1946 and 1958 on Bikini Atoll in the Marshall Islands. Tests occurred at 7 test sites on the reef itself, on the sea, in the air, and underwater. The test weapons produced a combined fission yield of 42.2 Mt of TNT in explosive power. The United States and its allies were engaged in a Cold War nuclear arms race with the Soviet Union to build more advanced bombs from 1947 until 1991. The first series of tests over Bikini Atoll in July 1946 was codenamed Operation Crossroads. ''Able'' was dropped from an aircraft and detonated above the target fleet. The second, ''Baker'', was suspended under a barge. It produced a large Wilson cloud and contaminated all of the target ships. Chemist Glenn T. Seaborg, the longest-serving chairman of the Atomic Energy Commission, called the second test "the world's first nuclear disaster." The second series of tests in 1954 was code ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozone Depletion
Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events. The main causes of ozone depletion and the ozone hole are manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants, and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). These compounds are transported into the stratosphere by turbulent mixing after being emitted from the surface, mixing much faster than the molecules can settle. Once in the stratosphere, they release atoms from the halogen group through photodissociation, which ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorofluorocarbon
Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon. The most common representative is dichlorodifluoromethane (R-12 or Freon-12). Many CFCs have been widely used as refrigerants, propellants (in aerosol applications), and solvents. Because CFCs contribute to ozone depletion in the upper atmosphere, the manufacture of such compounds has been phased out under the Montreal Protocol, and they are being replaced with other products such as hydrofluorocarbons (HFCs) including R-410A and R-134a. Structure, properties and production As in simpler alkanes, carbon in the CFCs bond with tetrahedral symmetry. Because the fluorine and chlorine atoms differ greatly in size and effective charge from hydrogen and from each other, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Lovelock
James Ephraim Lovelock (26 July 1919 – 26 July 2022) was an English independent scientist, environmentalist and futurist. He is best known for proposing the Gaia hypothesis, which postulates that the Earth functions as a self-regulating system. With a PhD in medicine, Lovelock began his career performing cryopreservation experiments on rodents, including successfully thawing frozen specimens. His methods were influential in the theories of cryonics (the cryopreservation of humans). He invented the electron capture detector, and using it, became the first to detect the widespread presence of chlorofluorocarbons in the atmosphere. While designing scientific instruments for NASA, he developed the Gaia hypothesis. In the 2000s, he proposed a method of climate engineering to restore carbon dioxide–consuming algae. He was an outspoken member of Environmentalists for Nuclear Energy, asserting that fossil fuel interests have been behind opposition to nuclear energy, citing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dobson Ozone Spectrophotometer
The Dobson spectrophotometer, also known as Dobsonmeter, Dobson spectrometer, or just Dobson is one of the earliest instruments used to measure atmospheric ozone. History The Dobson spectrometer was invented in 1924 by Gordon Dobson. A history of the development of the instrument is here and an example of one of Dobson's own instruments remains on display in the University of Oxford Department of Physics. Operation Dobson spectrophotometers can be used to measure both total column ozone and profiles of ozone in the atmosphere. Ozone is tri-atomic oxygen, O3; ozone molecules absorb harmful UV light in the atmosphere before it reaches the surface of the earth. No UVC radiation penetrates to the ground as it is absorbed in the ozone-oxygen cycle. However some longer-wave and less harmful UVB and most of the UVA is not absorbed as ozone is less opaque to these frequencies, so they penetrate to the ground level of Earth in higher quantities. The sources of light used may vary. Be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozone Layer
The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately above Earth, although its thickness varies seasonally and geographically. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Measurements of the sun showed that the radiation sent out from its surface and reaching the ground on Earth is usually consistent with the spectrum of a black body with a temperature in the range of , except that there was no radiation below a wavelength of about 310 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide In Earth’s Atmosphere
Carbon dioxide in Earth's atmosphere is a trace gas that plays an integral part in the greenhouse effect, carbon cycle, photosynthesis and oceanic carbon cycle. It is one of several greenhouse gases in Earth's atmosphere that are contributing to climate change due to increasing emissions of greenhouse gases from human activities. The current global average concentration of CO2 in the atmosphere is 421 ppm as of May 2022. This is an increase of 50% since the start of the Industrial Revolution, up from 280 ppm during the 10,000 years to the mid-18th century. The increase is due to human activity. Burning fossil fuels is the main cause of these increased CO2 concentrations and also the main cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles David Keeling
Charles David Keeling (April 20, 1928 – June 20, 2005) was an American scientist whose recording of carbon dioxide at the Mauna Loa Observatory confirmed Svante Arrhenius's proposition (1896) of the possibility of anthropogenic contribution to the greenhouse effect and global warming, by documenting the steadily rising carbon dioxide levels. The Keeling Curve measures the progressive buildup of carbon dioxide, a greenhouse gas, in the atmosphere. Early life and early career Keeling was born in Scranton, Pennsylvania, to Ralph Keeling and Grace L Keeling (née Sherberne). His father, an investment banker, excited interests of astronomy in a 5-year-old Charles, while his mother instilled a lifelong love of music. He graduated with a degree in chemistry from the University of Illinois in 1948. Charles Keeling earned a PhD in chemistry from Northwestern University in 1953 under Malcolm Dole, a polymer chemist. Most of Dole's graduates were going straight into the oil industry; Kee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mauna Loa Observatory
The Mauna Loa Observatory (MLO) is an atmospheric baseline station on Mauna Loa, on the island of Hawaii, located in the U.S. state of Hawaii. The observatory Since 1958, initially under the direction of Charles Keeling, followed by his son Ralph and later Elmer Robinson, Mauna Loa Observatory (MLO) has been monitoring and collecting data relating to atmospheric change, and is known especially for the continuous monitoring of atmospheric carbon dioxide (CO2), which is sometimes referred to as the Keeling Curve. The observatory is under the Earth System Research Laboratory which is part of the National Oceanic and Atmospheric Administration (NOAA). According to the NOAA, Mauna Loa is the world's oldest continuous CO2 monitoring station, and the world's primary benchmark site for measurement of the gas. The latest observation of CO2 concentrations from MLO can be found at web sites along with data from other sites and trends at Mauna Loa. The MLO levels can be compared wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenhouse Gas
A greenhouse gas (GHG or GhG) is a gas that Absorption (electromagnetic radiation), absorbs and Emission (electromagnetic radiation), emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Atmosphere of Earth, Earth's atmosphere are water vapor (), carbon dioxide (), methane (), nitrous oxide (), and ozone (). Without greenhouse gases, the average temperature of Earth#Surface, Earth's surface would be about , rather than the present average of . The atmospheres of atmosphere of Venus, Venus, atmosphere of Mars, Mars and atmosphere of Titan, Titan also contain greenhouse gases. Human activities since the beginning of the Industrial Revolution (around 1750) have increased the Carbon dioxide in Earth's atmosphere, atmospheric concentration of carbon dioxide by over 50%, from 280 parts per million, ppm in 1750 to 421 ppm in 2022. The last time the atmospheric concentration of carbon dioxide was this high was over 3&nbs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partial Nuclear Test Ban Treaty
The Partial Test Ban Treaty (PTBT) is the abbreviated name of the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, which prohibited all test detonations of nuclear weapons except for those conducted underground. It is also abbreviated as the Limited Test Ban Treaty (LTBT) and Nuclear Test Ban Treaty (NTBT), though the latter may also refer to the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which succeeded the PTBT for ratifying parties. Negotiations initially focused on a comprehensive ban, but that was abandoned because of technical questions surrounding the detection of underground tests and Soviet concerns over the intrusiveness of proposed verification methods. The impetus for the test ban was provided by rising public anxiety over the magnitude of nuclear tests, particularly tests of new thermonuclear weapons (hydrogen bombs), and the resulting nuclear fallout. A test ban was also seen as a means of slowing nuclear proliferati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
