Of or pertaining to the air, atmosphere, or aviation. Also, same as antenna.

A line drawn through all points on a map having the same amount of cloudiness.

An Instrument used to determine dew point.

Abbreviation for mean sea level.

A halo phenomenon consisting of a horizontal circle passing through the moon, corresponding to the parhelic circle through the sun. Produced by reflection of moonlight from ice crystals.

That horizontal wind velocity at which the Coriolis acceleration exactly balances the horizontal pressure force. It is directed along contour lines or isobars.

An evaluation, according to set procedures, of those weather elements which are most important for aircraft operations. Always includes cloud height or vertical visibility, sky cover, visibility, obstructions to vision, certain atmospheric phenomena, and ...

A thermometer using transducing elements which deform with temperature. Examples are the bimetallic thermometer and the Bourdon tube type of thennometer.

An instrument which indicates the presence of precipitation. The ombroscope consists of a heated, water-sensitive surface which indicates by mechanical or electrical techniques the occurrence of precipitation.

A general term for instruments which sample atmospheric suspensoids by impaction. Same as impactometer.

A clock-driven device for recording the time of occurrence of an event or the time interval between the occurrence of events.

Readily taking up and retaining moisture.

The maximum rate at which precipitation can pass through the surface into the soil, for a given soil in a given condition.

The study of waters (including oceans, lakes, and rivers) embracing either: (a) their physical characteristics, from the standpoint of the oceanographer or limnologist; or (b) the elements affecting safe navigation, from the point of view of the mariner. ...

A small balloon used to determine the height of the cloud base. The height can be computed from the ascent velocity of the balloon and the time required for its disappearance into the cloud.

A temperature telemeter.

A motorlike device containing a rotor and a stator and capable of converting an angular position into an electrical signal, or an electrical signal into an angular position. When several synchros are correctly connected, all of the rotors will align thems ...

Abbreviation for the pressure, temperature, and humidity data obtained by a radiosonde observation.

A remote indicator for wind speed and direction used in conjunction with a contact anemometer and a wind vane. The indicator consists of a center light, connected to the contact anemometer, surrounded by eight equally spaced lights which are individually ...

An up slope wind due to local surface heating. Opposite of katabatic wind.