Instrument for measuring the depth of water from precipitation that is assumed to be distributed over a horizontal, impervious surface and not subject to evaporation.

The maximum distance, usually horizontally, at which a given object or light source is just visible under particular conditions of transmittance and background luminance.

A reflecting type telescope with a 45

In radiometry, a measure of the intrinsic radiant intensity emitted by a radiator in a given direction.

The mean difference between the readings of a given instrument and those of a standard instrument.

Instrument which measures and records the amount of evaporation over time.

An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

Same as atmometer.

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 ...

A mercury barometer designed for use aboard ship. The instrument is of the fixed-cistern type (see Kew barometer). The mercury tube is constructed with a wide bore for its upper portion and with a capillary bore for its lower portion. This is done to incr ...

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

An area of low barometric pressure, with its attendant system of winds. Also called a depression or cyclone.

A refraction phenomenon similar to a parahelion, but occurring generally at a distance of 120

Thermodynamic change of state of a system in which there is transfer of heat across the boundaries of the system. Compare to adiabatic process.

Frozen or partly frozen rain.

A relatively small-scale, upward moving current of air.

A component of a radiosonde consisting of a series of alternate electrically conducting and insulating strips. As these are scanned by a contact the radiosonde transmits temperature and humidity signals alternately. The contact may be a baroswitch as in t ...

A self-recording psychrometer.

A type of electrical thermometer consisting of two thermocouples which are series-connected with a potentiometer and a constant-temperature bath. One couple, called the reference junction, is placed in a constant-temperature bath, while the other is used ...

Rate of wind movement in distance per unit time.