atmosphere
A widespread body of air in which its homogeneous properties were established while that air was over a particular region of the earth's surface and that undergoes specific modifications while moving away from its source region.
What is air mass ?
The heights above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as "broken," "overcast," or "obscuration," and not classified as "thin" or "partial."
What is ceiling ?
A precautionary procedure that provides protection against the formation of frost and/or ice and the accumulation of slush and/or snow on treated surfaces of an aircraft for a period of time during active frost, frozen precipitation, and freezing precipitation.
What is anti-icing ?
Any rapid, horizontal, or vertical change in wind direction or speed.
What is wind shear ?
The speed of an aircraft relative to its surrounding air mass.
What is airspeed ?
A boundary between air masses of different temperatures and moisture.
What is front ?
Large clouds in which smaller droplets continue to collide and join together until a significantly larger droplet is formed.
What are cumulous clouds ?
Any frost, ice, slush or snow that adheres to the critical surfaces of an aircraft.
What is contamination ?
Precipitation consisting of small balls or pieces of ice with a diameter ranging from 5 mm to greater than 50 mm falling either separately or agglomerated.
What is hail ?
Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling less than the minima specified for visual meteorological conditions.
What is IMC ?
Atmospheric condition where temperature increases with altitude.
What is inversion ?
Clouds of extensive horizontal development and a stable air mass.
What are stratus clouds ?
The growth of ice on aircraft surfaces in flight as a result of the collision with supercooled liquid water cloud droplets.
What is accretion ?
These are a type of precipitation consisting of transparent or translucent pellets of ice, 5 mm or less in diameter. They may be spherical, irregular, or (rarely) conical in shape.
What are ice pellets ?
The continuous broadcast of recorded noncontrol information in selected terminal areas. Its purpose is to improve controller effectiveness and to relieve frequency congestion by automating the repetitive transmission of essential but routine information;
What is ATIS ?
The ratio, expressed as a percentage, of water vapor present compared with the maximum amount possible at the present temperature.
What is relative humidy ?
The temperature at which water vapor will begin to condense.
What is dew point ?
Ice crystals that form from ice saturated air saturated with vapor at temperatures below 0°C (32°F) by direct sublimationdeposition on the ground or other exposed objects.
What is frost ?
Fairly uniform precipitation composed exclusively of fine drops (diameter less than 0.5 mm [0.02in]) very close together which freezes upon impact with the ground or other exposed objects.
What is freezing drizzle ?
Water that remains in the liquid state even though temperatures are below 0°C. Cloud droplets can exist as a liquid at temperatures down to about -40°C.
What is supercooled water ?
The property of an air mass to resist vertical displacement from its initial position. Then an outside force is required to raise it for cloud formation.
What is stability ?
The ice type that appears rough, milky and opaque.
What is rime ice ?
Snow that has a water content exceeding its freely drained condition such that it takes on fluid properties (e.g., f lowing and splashing).
What is slush ?
A report of meteorological phenomena encountered by aircraft in flight.
What is PIREP ?