Nested Grid Model generated every 12 hours by NCEP.

The energy of any type of electromagnetic radiation. Also called radiation.

A recording hair hygrometer.

An instrument which indicates the presence of precipitation. The ombroscope consists of a heated, water-sensitive surface which indicates by mechanical or electrical techniques the occurrence of precipitation.

A device, similar to a potometer, for measuring transpiration, consisting of a vessel containing soil in which one or more plants are rooted and sealed so that water can escape only by transpiration from the plant.

The play or loose motion in an instrument due to the clearance existing between mechanically contacting parts.

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.

See ceilometer.

An instrument used for measuring the specific gravity of a liquid.

That part of an audio-modulated radiosonde consisting of the baroswitch, the sensing elements, the reference elements, and the relay.

Amount of water, expressed as a depth or as a mass, which would be obtained if all the water vapor in a specified column of the atmosphere were condensed and precipitated.

See bimetallic thermometer.

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

A type of pressure-tube anemometer, named after the inventor.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

The nautical mile is closely related to the geographical mile which is defined as the length of one minute of arc on the earth's equator. By international agreement, the nautical mile is now defined as 1852 meters.

Same as instrument shelter.

A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume, and pressure is the thermometric property, and (b) a type in which the gas is kept at constant pres ...

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.

An automatic, recording cloud height indicator.