A spring which is designed to achieve a fixed spring constant over a wide temperature range. Usually, this involves an alloy with high nickel content such as Ni-Span C. It is common for these springs to be stress relieved at elevated temperature after for ...

An early and once universal name for the mercury barometer.

modulated radiosonde-A radiosonde which transmits the indications of the meteorological sensing elements in the form of pulses spaced in time. The meteorological data are evaluated from the intervals between the pulses. Also called timeinterval radiosonde ...

See hurricane beacon.

A thermograph in which ventilation is provided by a suction fan.

Overflowing by water of the normal confines of a stream or other body of water, or accumulation of water by drainage over areas which are not normally submerged.

The volume of water required to cover one acre to a depth of one foot: 43,560 cubic feet.

Programmable Read-Only Memory. Read-only memory which can be programmed by the user using a special hardware programmer.

A class of rain gauge in which the level of the collected rain water is measured by the position of a float resting on the surface of the water.

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

A unit of energy per unit area commonly employed in radiation theory. Equal to one gram-calorie per square centimeter.

A plastic molding component formed by the reaction of phenol and formaldehyde. It can be heavily reinforced or "filled" with glass fibers or other materials. Phenolics are known for their high impact strength, excellent wear characteristics, and dimension ...

The total of direct solar radiation and diffuse sky radiation received by a unit horizontal surface. Global radiation is measured by pyranometers.

A measurement of atmospheric conditions aloft, above the effective range of a surface weather observation. Elements evaluated include temperature, humidity, pressure, wind speed, and wind direction.

An instrument designed to measure quantities of heat. Sometimes used in meteorology to measure solar radiation.

The outer, solid portion of the earth: the crust of the earth.

A hygrometer in which the sensitive element is a strand or strands of human hair, the length of which is a function of the relative humidity of the air.

An absolute temperature scale with the degree of the Fahrenheit scale and the zero point of the Kelvin scale. The freezing point of water equals 491.69

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

A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.