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The international definition of fog is a visibility of less than 1 km (3,300 ft); mist is a visibility of between 1 km (0.62 mi) and 2 km (1.2 mi) and haze from 2 km (1.2 mi) to 5 km (3.1 mi). Fog and mist are generally assumed to be composed principally of water droplets, haze and smoke can be of smaller particle size.
Prevailing visibility in aviation is a measurement of the greatest distance visible throughout at least half of the horizon, not necessarily continuously. To take the prevailing visibility, controllers reference a number of visual reference points: usually buildings, hills, or other geographic features. The value obtained is usually reported on ...
Weather radar in Norman, Oklahoma with rainshaft Weather (WF44) radar dish University of Oklahoma OU-PRIME C-band, polarimetric, weather radar during construction. Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.).
The difference between the forecast and the actual weather outcome for forecasts 3, 5, 7, and 10 days in advance. It was not until the 20th century that advances in the understanding of atmospheric physics led to the foundation of modern numerical weather prediction .
Also actiniform. Describing a collection of low-lying, radially structured clouds with distinct shapes (resembling leaves or wheels in satellite imagery), and typically organized in extensive mesoscale fields over marine environments. They are closely related to and sometimes considered a variant of stratocumulus clouds. actinometer A scientific instrument used to measure the heating power of ...
Radar is a system that uses radio waves to determine the distance (ranging), direction (azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method [ 1 ] used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain.
A trough is the result of the movements of the air in the atmosphere. In regions where there is upward movement near the ground and divergence at altitude, there is a loss of mass. The pressure becomes lower at this point. At upper levels of the atmosphere, this occurs when there is a meeting of a mass of cold air and another hot one along a ...
Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not begin until the 18th century. The 19th century saw modest progress in the field after weather ...