A pressure-plate anemometer consisting of a plate which is free to swing about a horizontal axis in its own plane above its center of gravity. The angular deflection of the plate is a function of the wind speed. This instrument is not used for station mea ...

The stage on a fixed river gauge at which it is necessary to begin issuing warnings or river forecasts if adequate precautionary measures are to be taken before flood stage is reached.

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 ...

The statement that the viscosity of air is independent of the density of air.

An instrument for recording global solar radiation.

Same as fogbow.

A method of winds aloft observation accomplished by tracking a balloon-borne radar target or radiosonde with either radar or a radio theodolite.

A point (or line) on a scale used for reference or comparison purposes. In calibration of meteorological thermometers, for example, the fiducial points are 100

Electromagnetic radiation of shorter wavelength than visible radiation but longer than x-rays, between 0.02 and 0.4 micron (200 and 4000 angstrom).

The minimum temperature shown by a minimum thermometer exposed in an open situation with its bulb at the level of the tops of the grass blades of short turf.

The distance or length of flow of the air past a point during a given interval of time.

NEXt Generation RADar. A NWS network of about 140 Doppler radars operating nationwide.

A thermometer with a muslin-covered bulb which is moistened. used to measure wet-bulb temperature.

A common unit used in measurement of atmospheric pressure. Defined as that pressure exerted by a one-inch column of mercury at standard gravity and a temperature of 0'C.

A type of pressure-plate anemometer in which the plate, restrained by a stiff spring, is held perpendicular to the wind. The wind-activated motion of the plate is measured electrically. The natural frequency of this system can be made high enough so that ...

An instrument which measures the effective terrestrial radiation. See Angstrom pyrgeometer.

Extended Binary Coded Decimal Interchange Code. A standard code used to represent data using 8 bits per character.

A device, similar to a potometer, for measuring transpiration, consisting of a vessel containing soil in which one or more plants are rooted and sealed so that water can escape only by transpiration from the plant.

An instrument for determining the direction from which radio waves approach a receiver. It may consist of a manually operated direction indicator, or it may use a servo system to position the antenna automatically in the direction of the incident waves.

Same as instrument shelter.