- 行业: Weather
- Number of terms: 60695
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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, ...
The addition of agents (aerosol, small ice particles) that will alter the phase and size distribution of cloud particles, with the intent of influencing precipitation. The most frequently used agents are granulated solid carbon dioxide (dry ice), silver iodide aerosol for initiation of the ice phase, and salt (sodium chloride) for initiation of larger cloud droplets. Many other agents (e.g., organic materials, bacteria) have been tested and proposed for use. The intent of cloud seeding is to modify or alter the natural development of the cloud so as to enhance or redistribute precipitation, suppress hail formation, dissipate fog or stratus cloud, or suppress lightning. Cloud seeding may involve different techniques. Particles may be released from the ground, from aircraft, or from rockets. The goal of ice phase cloud seeding is to induce the phase transition from a supercooled water cloud to one composed partially or entirely of ice. The goal of dynamic cloud seeding is to stimulate or enhance vertical air motions in the cloud through increased buoyancy derived from the release of latent heat of freezing. Hygroscopic seeding utilizes hygroscopic salt aerosols that readily condense water and may grow large enough to become centers for coalescence growth of precipitation.
Industry:Weather
The action by which the surface of a liquid in contact with a solid (as in a capillary tube) is elevated or depressed depending on the relative attraction of the molecules of the liquid for each other and for those of the solid (e.g., the meniscus of a liquid column). See capillary action, capillary depression.
Industry:Weather
The acceleration on a particle moving in a curved path, directed toward the instantaneous center of curvature of the path, with magnitude V2/R, where V is the speed of the particle and R the radius of curvature of the path. This acceleration is equal and opposite to the centrifugal force per unit mass.
Industry:Weather
The absorption of electromagnetic radiation within a cloud. With some exceptions, clouds typically absorb ≈10% of the (broadband) shortwave radiation and ≈95% of the longwave radiation incident on their boundaries. Thin clouds, notably thin cirrus, may absorb considerably less. The dominant absorber tends to be the water droplets or ice crystals making up the cloud, with water vapor playing a matching role only for shortwave absorption by upper tropospheric clouds.
Industry:Weather
Term used loosely to denote the right conical space with apex at some ground target and within which an aircraft must be located if the pilot is to be able to discern the target while flying at a specified altitude. Because the aircraft's altitude must be specified before this term can be given definite meaning, it might better be replaced by some such term as “circle of visibility. ”
Industry:Weather
That portion of the earth where natural materials (water, soil, etc. ) occur in frozen form. Generally limited to the polar latitudes and higher elevations.
Industry:Weather
That portion of the microclimate that is directly attributable to the small- scale variations of ground level. A great many microclimatic variations are caused by small differences in elevation, steepness of slope, and direction of slope exposure and direction of curvature. These influence the total amount of heat absorbed from solar radiation, the heat loss by outgoing radiation, the small- scale (gravity) airflow in the boundary layer near the soil, and the runoff of precipitation. Such microclimatic differences can be observed even on as small a scale as the ridges and furrows of plowed fields or mounded flower beds.
Industry:Weather
Term applied to schemes for artificially altering or controlling the climate of a region. See climatic control; compare weather modification.
Industry:Weather
Studies that attempt to evaluate or predict the impact of climate change on physical and ecological systems, human health, and socioeconomic sectors. The potential sensitivity, adaptability, and vulnerability of these systems and sectors to climate change can be estimated.
Industry:Weather
Structure of small-scale cloud features (cells, billows, wisps, etc. ) resulting from the distribution of cloud particles on a scale larger than the particles themselves but smaller than the scale of the visual cloud. Such features may result from local motions, organized or turbulent, and be preferred sites for the development of cloud hydrometeors.
Industry:Weather
