See hook gauge.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

The ratio of the actual amount of water evaporated into the atmosphere to the evaporative power. Also called relative evaporation.

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

An instrument used to measure the water vapor content of the air.

A graphical representation of a frequency distribution. The range of the variable is divided into class intervals for which the frequency of occurrence is represented by a rectangular column. The height of the column is proportional to the frequency of ob ...

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

An instrument which measures the transmissivity of the atmosphere between two points for the determination of visual range.

For a given locality and month, an empirical expression devised for the purpose of classifying climates numerically on the basis of precipitation and evaporation.

The portion of the precipitation on the land which ultimately reaches the streams. especially the water from rain or melted snow that flows over the surface.

A nephoscope in which the motion of the cloud is observed by its reflection in a mirror.

Anemometer which measures wind speed by measuring the degree of cooling of a metal film heated by an electric current. A type of cooling-power anemometer.

A system of physical units based upon the use of the meter, the metric ton (106 grams), and the second as elementary quantities of length, mass, and time, respectively.

An instrument used to measure the amount of dew formed on a given surface.

An instrument which measures the instantaneous rate at which rain is falling on a given surface. Also called a rate-of-rainfall gauge.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

Transistor-Transistor Logic.

A standard unit of atmospheric pressure, defined as the pressure exerted by a 760 mm column of mercury at standard gravity (980.665 cm/sec2 ) at O

An aviation weather forecast for a specific flight.

The center of an area of high pressure, usually accompanied by anticyclonic and outward wind flow. Also known as an anticyclone.