- 行业: Weather
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The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, AMS has a membership of more than 14,000 professionals, ...
Organic compound formed in the atmosphere from the addition of nitrogen dioxide, NO<sub>2</sub>, to the peroxyacyl radical formed in the oxidation of acetaldehyde. PAN and its larger homologs are irritants to the eyes and breathing system. They are formed in dangerous levels in photochemical smogs. The PANs are thermally quite stable “reservoir” species and can transport active nitrogen from polluted to pristine regions.
Industry:Weather
A region in the lower stratosphere (approximately 15–25 km in altitude and worldwide) where submicrometer-sized particles composed of aqueous sulfuric acid are present. Oxidation of sulfur compounds (primarily carbonyl sulfide, OCS, and sulfur dioxide, SO<sub>2</sub>) is believed to be the source of sulfuric acid (H<sub>2</sub>SO<sub>4</sub>). Volcanic eruptions directly inject large quantities of H<sub>2</sub>S or SO<sub>2</sub> into the stratosphere, causing large increases in the amount of particulate sulfuric acid. The particles undergo a slow falling-out process (timescale of years) into the lower atmosphere. Because these sulfuric acid particles are present in the ozone layer, heterogeneous chemical reactions that occur on them can have a significant effect on ozone by influencing the abundance of trace species that affect ozone concentrations.
Industry:Weather
A region in the lower stratosphere (approximately 15–25 km in altitude and worldwide) where submicrometer-sized particles composed of aqueous sulfuric acid are present. Oxidation of sulfur compounds (primarily carbonyl sulfide, OCS, and sulfur dioxide, SO<sub>2</sub>) is believed to be the source of sulfuric acid (H<sub>2</sub>SO<sub>4</sub>). Volcanic eruptions directly inject large quantities of H<sub>2</sub>S or SO<sub>2</sub> into the stratosphere, causing large increases in the amount of particulate sulfuric acid. The particles undergo a slow falling-out process (timescale of years) into the lower atmosphere. Because these sulfuric acid particles are present in the ozone layer, heterogeneous chemical reactions that occur on them can have a significant effect on ozone by influencing the abundance of trace species that affect ozone concentrations.
Industry:Weather
A zone of sorted soil particles oriented as one of several alternating bands of coarse and fine material appearing on the soil surface and commonly aligned parallel to downslope transport on hillslopes.
Industry:Weather
1. The probability distribution specifying the exceedance probability of different rainfall depths for a given duration (such as 1 hour, or a 24-hour day). The exceedance frequency is often reported as a return period (in years), which is the reciprocal of the annual exceedance frequency. 2. The expected number of times, during a specified time period, that a given precipitation depth will be exceeded.
Industry:Weather
Strong straight-line winds associated with nontornadic outflow from strong thunderstorms. Used by Canadian meteorologists, particularly in Manitoba; no longer used in the United States. See'' also'' derecho, downburst.
Industry:Weather
(In meteorology, also called barometric gradient. ) The rate of decrease (gradient) of pressure in space at a fixed time. The term is sometimes loosely used to denote simply the magnitude of the gradient of the pressure field.
Industry:Weather
Designation for the study of those phenomena that lie wholly or in part outside the earth's atmosphere. The term is analogous to terrestrial meteorology in that it includes the study of planetary atmospheres and solar–weather relationships.
Industry:Weather
A thermodynamic process in which a substance changes from one phase to another. A phase change entails discontinuity. At a given temperature, two phases of a pure, homogeneous substance are characterized by different enthalpies (and entropies), and the enthalpy difference is called latent heat. The phase transitions of greatest importance to meteorology are those between water vapor, liquid water, and ice.
Industry:Weather
