General term for an instrument used to make direct measurements of visual range or measurements of the physical characteristics of the atmosphere which determine the visible range.

In general, any object that reflects incident energy. Usually it is a device designed for specific reflection characteristics.

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

A unit of signaling speed representing the number of code elements sent per second; often, bits per second.

An anemometer which measures wind speed in terms of the drag which the wind exerts on a solid body. See bridled-cup anemometer, normal-plate anemometer, pendulum anemometer.

An instrument for measuring the pressure of gases and vapors. A mercury barometer is a type of manometer.

The closeness of agreement among a number of consecutive output values measuring the same input value under the same operating conditions, approaching from the same direction. Usually measured as nonrepeatability but expressed as repeatability, a percenta ...

In general, solar radiation received at the earth's surface. Contracted from incoming solar radiation.

The unit of force in the centimeter-gram-second system of physical units, i.e. one gm cm per sec2, equal to 7.233 x 10-5 poundal.

Sir Napier Shaw's name for the approximate absolute temperature scale,

The writing component of a recording instrument.

A severe weather condition characterized by low temperatures and strong winds bearing a great amount of snow, either falling or picked up from the ground.

A photometric unit of illuminance or illumination equal to one lumen per square centimeter.

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

check chamber-A chamber use to check the sensing elements of radiosonde equipment.

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

That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

Balance of the water resources of a region, comparing precipitation and inflow with outflow, evaporation, and accumulation.

Precipitation falling from a cloud, usually in wisps or streaks, but evaporating before it reaches the ground.

A protocol similar to RS232 which permits data interchange on multidrop networks of up to 32 nodes using a single twisted pair cable. In order for this protocol to be used, each device on a network must have some level of intelligence in order establish o ...