Same as wind sock.

Federal Aviation Administration.

A self-recording psychrometer.

Wind with a speed between 48 and 55 knots (55 and 63 mph), Beaufort scale number 10.

Same as rain gauge.

Capacity of a soil or other surface to be penetrated by water sinking into the ground under the force of gravity. It thus expresses the rate of percolation.

The array of indicating marks and figure in relation to which the position of an index is observed, i.e. a scale plate on a recorder.

Wind with a speed between 22 and 27 knots (25 and 31 mph); Beaufort scale number 6.

A radiosonde whose carrier wave is modulated by audio-frequency signals whose frequency is controlled by the sensing elements of the instrument.

The interval between the lower and upper measuring limits of an instrument, i.e. a thermometer with a range of -35 to 50

The water portion of the earth as distinguished from the solid part, called the lithosphere, and from the gaseous outer envelope, called the atmosphere.

Fine dust or salt particles dispersed through a portion of the atmosphere; a type of lithometer. The particles are so small they cannot be felt or seen with the naked eye. Many haze formations are caused by the presence of an abundance of condensation nuc ...

General name for an instrument designed to measure the vertical component of the wind speed. See anemoclinometer.

Phase Shift Keying. A form of phase modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.

Generally, a measure of the departure of the mean daily temperature from a given standard, one degree day for each degree (

A systematic observational error due to the characteristics of the observer. The uncertainty in a reading made by an observer may be acertained by a statistical analysis of his or her readings.

The stage, on a fixed river gauge, corresponding to the top of the lowest banks within the reach for which the gauge is used as an index. Compare to flood stage.

In a radiosonde observation, a level (other than a standard level) for which values of pressure, temperature, and humidity are reported because temperature and/or humidity data at that level is sufficiently important or unusual to warrant the attention of ...

Rain gauge which registers precipitation that is too light to be registered by ordinary recording of the depth of water from precipitation. Same as ombrometer.