A thermoelectric thermometer used for measuring air temperature. The name is derived from the fact that the reference thermocouple is placed in an insulated bottle.

A thermometer consisting of a clock mechanism the speed of which is a function of temperature.

A rain gauge or array of rain gauges designed to measure the inclination and direction of falling rain.

The atmospheric pressure at mean sea level either directly measured by stations at sea level or empirically determined from the station pressure and temperature by stations not at sea level. Used as a common reference for analyses of surface pressure patt ...

A instrument designed to study small fluctuations of some quantity. The microbarograph is an example of a recording pressure variometer.

Air in motion relative to the surface of the earth. Almost exclusively used to denote the horizontal component.

A type of cloud height indicator which uses a searchlight to project vertically a narrow beam of light onto the cloud base. The height of the cloud is determined using a clinometer, located at a known distance from the ceiling light, to measure the angle ...

Situated on the side from which the wind blows.

See feed.

General name for an instrument which measures the earth's magnetic field intensity.

Generally, an instrument designed to measure or estimate the blueness of the sky. See Linke-scale.

A decrease in the central pressure of a pressure system. Usually applied to a low rather than to a high.

A device for measuring sea-surface waves. It consists of a weighted pole below which a disk is suspended at a depth sufficiently deep for the wave motion associated with deepwater waves to be negligible. The pole will then remain nearly as if anchored to ...

See radiosonde commutator.

The height of the cloud base above the local terrain.

A very sensitive electrostatic electrometer for measuring small potential differences.

Any sudden and heavy rain, almost always of the shower type.

An absolute pyhrliometer, developed by C.G. Abbott, in which the radiation-sensing element is a blackened water-calorimeter.

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

An instrument which determines the black-body temperature of a substance by measuring its thermal radiation.