A hygrometer which uses a transducing element whose electrical properties are a function of atmospheric water vapor content. The humidity strip and carbon-film hygrometer element are examples of such a transducer.

A large plastic constant-level balloon for duration flying (in excess of 24 hours) at altitudes above 40,000 feet, used for the determination of wind fields and the measurement of upper atmospheric parameters.

Wind with a speed between 56 and 63 knots (64 and 72 mph); Beaufort scale number 11.

A radiosonde which transmits the indication of the meteorological sensing elements in the form of a code consisting of combinations of dots and dashes.

In general, any self-recording instrument carried aloft by any means to obtain meteorological data.

In physics, any process in which the flux density (or power, amplitude, intensity, illuminance, etc.) of a "parallel beam" of energy decreases with increasing distance from the source. Attenuation is always due to the action of the transmitting medium its ...

Same as river gauge.

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.

Same as recording rain gauge.

Solar radiation scattered by particles in the atmosphere.

A forecast of the expected stage or discharge at a specified time, or of the total volume of flow within a specified Interval of time, at one or more points along a stream.

An instrument for taking photographs of an image of the sun in monochromatic light.

An instrument used to reveal but not necessarily measure the presence of an electrical quantity. It is used to display the output of a sensing element after suitable amplification and modification. Sometimes called display.

A sudden brief increase in the speed of the wind, followed by a lull or slackening. Compare to peak gust.

The direction, with respect to magnetic north, from which the wind is blowing. Distinguish from true wind direction.

The process by which small particles suspended in a medium of a different refractive index diffuse a portion of the incident radiation in all directions. In scattering no energy transformation results, only a change in the spatial distribution of the radi ...

An inert gas. An element found in the atmosphere to the extent of only 0.000114 percent by volume. Its molecular weight is 83.7.

A protective coating applied to circuits.

Old snow that has become granular and compacted as a result of melting and refreezing.

The process in which incident radiation is retained by a substance. A further process always results from absorption.