A wave resulting from the action of wind on a water surface.

A particular pattern of snow sampler having an internal diameter of 1.485 inches so that each inch of water in the sample weighs one ounce.

A hygrometer which includes an arrangement for the time recording of atmospheric humidity.

A line drawn through points of equal humidity on given surface.

Sustained winds greater than or equal to 40 mph or gust greater than or equal to 58 mph.

Name sometimes given to a transmissometer.

A water-temperature thermometer provided with an insulated container around the bulb. It is lowered into the sea on a line until it has had time to reach the temperature of the surface water, then withdrawn and read. The insulated water surrounding the bu ...

The ratio of the actual amount of water evaporated into the atmosphere to the evaporative power. Also called relative evaporation.

A type of photoelectric photometer used to measure high-altitude winds on the assumption that stellar scintillation is caused by atmospheric inhomogeneities being carried along by wind near the tropopause level.

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, for the recording of two or more meteorological parameters, in which the ventilation is provided by a suction fan.

National Weather Service. Administered by the U.S. Department of Commerce.

A type of cooling-power anemometer based upon the principle that the time constant of a thermometer is a function of its ventilation.

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

An instrument for measuring the pressure of the atmosphere. The two principle types are aneroid and mercurial.

A unit of distance equal to 5280 feet. It is sometimes referred to as a land mile.

A subtle, diumal component of the wind velocity leading to a diumal shift of the wind or turning of the wind with the sun, produced bv the east-to-west progression of daytime surface heating.

Operation mode of a communication circuit in which each end can transmit and receive, but not simultaneously.

A sunshine recorder of the type in which the time scale is supplied by the motion of the sun. It consists of two opaque metal semi-cylinders mounted with their curved surfaces facing each other. Each of the semi-cylinders has a short narrow slit in its fl ...

A vent used with pressure sensors to reduce the effect of wind on the pressure inlet. It is normally mounted remotely and connected to the sensor using airtight tubing.