An instrument for the measurement of the net flux of downward and upward total (solar and terrestrial) radiation through a horizontal surface.

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. T ...

An elongated area of relatively low atmospheric pressure. Usually associated with and most clearly identified as an area of maximum cyclonic curvature of the wind flow. The opposite of a ridge.

A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.

The unit of acceleration in the centimeter-gram-second system of units, equal to one cm per sec2. Commonly used in gravimetry.

The number of cycles per second between the limits of a frequency band.

A direct-vision nephoscope which is constructed in the following manner: a comb consisting of a crosspiece containing equispaced vertical rods is attached to one end of a column eight to ten feet long and is supported on a mounting that is free to rotate ...

A type of atmometer. It is a pan used in the measurement of the evaporation of water into the atmosphere. The NWS Class A pan is a cylindrical container 48 inches in diameter and 10 inches deep.

A type of directional antenna used on some types of radar and radio equipment consisting of an array of elemental, single- wire dipole antennas and reflectors.

The atmospheric pressure at the level of the barometer. May or may not be the same as station pressure.

Instrument used to measure the amount of water evaporated from the soil surface during a given time interval.

A rainbow of angular radius of about 50

An instrument of the aspiration condenser type which measures the concentration and mobility of small ions.

A protective coating applied to circuits.

An instrument for photographing the corona and prominences of the sun at times other than at solar eclipse.

The amount of moisture which, if available, would be removed from a given land area by evapotranspiration. Expressed in units of water depth.

An instrument, dropped from high attitude and carried by a stable parachute. used to measure the vertical component of turbulence aloft.

An anemometer utilizing the principle that the pitch of the aeolian tones generated by air moving past an obstacle is a function of the speed of the air. Largely a curiosity and has been put to no practical application in modem meteorology.

A recording hair hygrometer.

A very sensitive electrostatic electrometer for measuring small potential differences.