A pressure-plate anemometer consisting of a plate which is free to swing about a horizontal axis in its own plane above its center of gravity. The angular deflection of the plate is a function of the wind speed. This instrument is not used for station mea ...

See hydrologic accounting.

A line of equal or constant pressure.

The pressure exerted by the atmosphere as a consequence of gravitational attraction exerted upon the "column" of air lying directly above the point in question.

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

A type of instrument shelter. It is a wooden box painted white with double louvered sides and mounted on a stand four feet above the ground.

General term for an instrument which records the vertical electric current in the atmosphere.

See radiation shield.

An instrument which records the duration of sunshine and gives a quantitative measure of the amount of sunshine by the action of the sun's rays upon blueprint paper. A type of sunshine recorder.

Thermometer used for measuring the highest temperature attained during a given interval of time, for example, a day.

A cylinder installed in a body of water or an evaporation pan to hold a sensor, such as a float to measure water level or a hook gage. The stillwell is constructed so that there is free movement of water in and out of it, and it therefore provides a repre ...

Forecasting weather by the use of numerical models, run on high speed computers. Most of the NWP for the National Weather Service is done at the National Centers for Environmental Prediction (NCEP).

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

A rain gauge which indicates but does not record the amount of precipitation captured.

The temperature at which a solid substance undergoes fusion, i.e. melts, changes from solid to liquid form. All substances have their characteristic melting points. For very pure substances the temperature range over which the process of fusion occurs is ...

An instrument which automatically determines the size distribution of raindrops.

Diffuse solar radiation which has the same intensity in all directions.

Rate of flow of water past a point in a stream, expressed as volume per unit time, i.e. cubic feet per second.

Thermometer used for measuring the lowest temperature attained during a given interval of time, for example, a day.

Same as fogbow.