Nuclear weapon design The Trinity test of the Manhattan Project was the first detonation of a nuclear weapon, which lead J.
General[ edit ] "Nuclear winter," or as it was initially termed, "nuclear twilight," began to be considered as a scientific concept in the s, after it became clear that an earlier hypothesis, that fireball generated NOx emissions would devastate the ozone layerwas losing credibility. It was within this context that the climatic effects of soot from fires was "chanced upon" and soon became the new focus of the climatic effects of nuclear war.
Once the quantity of soot is decided upon by the researchers, the climate effects of these soot clouds are then modeled. Turco in reference to a 1-dimensional computer model created to examine the "nuclear twilight" idea, this 1-D model output the finding that massive quantities of soot and smoke would remain aloft in the air for on the order of years, causing a severe planet-wide drop in temperature.
Turco would later distance himself from these extreme 1-D conclusions. More recently, the same team of prominent modellers from the s have begun again to publish the outputs of computer models, these newer models produce the same general findings as their old ones, that the ignition of firestorms, each comparable in intensity to that observed in Hiroshima incould produce a "small" nuclear winter.
Robock has not modeled this, but has speculated that it would have global agricultural losses as a consequence. The only phenomenon that is modeled by computer in the nuclear winter papers is the climate forcing agent of firestorm-soot, a product which can be ignited and formed by a myriad of means.
These were speculated to be a possible result of any large scale employment of counter-value airbursting nuclear weapon use during an American-Soviet total war.
This larger number of firestorms, which are not in themselves modeled,  are presented as causing nuclear winter conditions as a result of the smoke inputted into various climate models, with the depths of severe cooling lasting for as long as a decade.
Independent of the team that continue to publish theoretical models on nuclear winter, inMike Fromm of the Naval Research Laboratoryexperimentally found that each natural occurrence of a massive wildfire firestorm, much larger than that observed at Hiroshima, can produce minor "nuclear winter" effects, with short-lived, approximately one month of a nearly immeasurable drop in surface temperatures, confined to the hemisphere that they burned in.
A suite of satellite and aircraft-based firestorm-soot-monitoring instruments are at the forefront of attempts to accurately determine the lifespan, quantity, injection height, and optical properties of this smoke. Presently, from satellite tracking data, stratospheric smoke aerosols dissipate in a time span under approximately two months.
Pyrocumulonimbus cloud Picture of a pyrocumulonimbus cloud taken from a commercial airliner cruising at about 10 km. Invarious sensing instruments detected 17 distinct pyrocumulonimbus cloud events in North America alone. At 10—15 kilometres 6—9 miles above the Earth's surface, the absorption of sunlight could further heat the soot in the smoke, lifting some or all of it into the stratospherewhere the smoke could persist for years if there is no rain to wash it out.
This aerosol of particles could heat the stratosphere and prevent a portion of the sun's light from reaching the surface, causing surface temperatures to drop drastically.
In this scenario it is predicted[ by whom? The modeled stable inversion layer of hot soot between the troposphere and high stratosphere that produces the anti-greenhouse effect was dubbed the "Smokeosphere" by Stephen Schneider et al.
Prior to the previously mentioned solar heating effect, the soot's injection height is controlled by the rate of energy release from the firestorm's fuel, not the size of an initial nuclear explosion. Despite the separation in time, ferocity and area burned, leading modelers of the hypothesis state that these five fires potentially placed five percent as much smoke into the stratosphere as the hypothetical nuclear-ignited fires discussed in modern models.
The exact timescale for how long this smoke remains, and thus how severely this smoke affects the climate once it reaches the stratosphere, is dependent on both chemical and physical removal processes. The chemical processes that affect the removal are dependent on the ability of atmospheric chemistry to oxidize the carbonaceous component of the smoke, via reactions with oxidative species such as ozone and nitrogen oxidesboth of which are found at all levels of the atmosphere,   and which also occur at greater concentrations when air is heated to high temperatures.
Historical data on residence times of aerosols, albeit a different mixture of aerosolsin this case stratospheric sulfur aerosols and volcanic ash from megavolcano eruptions, appear to be in the one-to-two-year time scale,  however aerosol—atmosphere interactions are still poorly understood. Tihomir Novakov and Aethalometer Sooty aerosols can have a wide range of properties, as well as complex shapes, making it difficult to determine their evolving atmospheric optical depth value.
These partially burnt "organics" as they are known, often form tar balls and brown carbon during common lower-intensity wildfires, and can also coat the purer black carbon particles. It depicts the findings of Soviet 3-D computer model research on nuclear winter fromand although containing similar errors as earlier Western models, it was the first 3-D model of nuclear winter.
The three dimensions in the model are longitude, latitude and altitude. The top image shows effects after 40 days, the bottom after days.
A co-author was nuclear winter modelling pioneer Vladimir Alexandrov. As ofthere remains ongoing speculation by friend, Andrew Revkinof foul play relating to his work. In a regional nuclear conflict scenario where two opposing nations in the subtropics would each use 50 Hiroshima -sized nuclear weapons about 15 kiloton each on major population centers, the researchers estimated as much as five million tons of soot would be released, which would produce a cooling of several degrees over large areas of North America and Eurasia, including most of the grain-growing regions.
The cooling would last for years, and, according to the research, could be "catastrophic". Nuclear summer[ edit ] A "nuclear summer" is a hypothesized scenario in which, after a nuclear winter has abated, a greenhouse effect then occurs due to carbon dioxide released by combustion and methane released from the decay of the organic matter that froze during the nuclear winter.
Ozone reaches its maximum concentration at about 25 km c. According to a document by the Defense Threat Reduction Agency ", this report was the initial study of the "nuclear winter" concept that was popularized by others decades later.
It indicated no appreciable chance of explosion-induced climate change. Further, solar radiation records reveal that none of the nuclear explosions to date has resulted in any detectable change in the direct sunlight recorded on the ground. Batten, while primarily analysing potential dust effects from surface bursts,  it notes that "in addition to the effects of the debris, extensive fires ignited by nuclear detonations might change the surface characteristics of the area and modify local weather patternsOccupational Employment and Wages, May Nuclear Medicine Technologists.
Prepare, administer, and measure radioactive isotopes in therapeutic, diagnostic, and tracer studies using a variety of radioisotope equipment. THIS MONTH IN JNM. FEATURED ARTICLE OF THE MONTH: Development of a SPECT Tracer to Image c-Met Expression in a Xenograft Model of Non–Small Cell Lung Cancer.
The "Journal of Cancer Research and Clinical Oncology" publishes significant and up-to-date articles within the fields of experimental and clinical oncology.
The journal, which is chiefly devoted to Original papers, also includes. The Nuclear Safety and Control Act provides for the appointment of not more than seven permanent Commission members by Order in Council and of temporary members.
One permanent member of the Commission is designated as the Canadian Nuclear Safety Commission's (CNSC's) President and Chief Executive Officer. Providing researchers with access to millions of scientific documents from journals, books, series, protocols and reference works.
Occupational Employment and Wages, May Nuclear Medicine Technologists. Prepare, administer, and measure radioactive isotopes in therapeutic, diagnostic, and tracer studies using a variety of radioisotope equipment.