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Exterior of a Stevenson screen

Interior of a Stevenson screen

A Stevenson screen or Instrument shelter is a meteorological screen to shield instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them.^[1] It forms part of a standard weather station. The screen creates, as near possible, a uniform environment in relation to the air outside. The Stevenson screen is usually designed to hold various instruments including thermometers (ordinary, maximum and minimum), a hygrometer, a dewcell, a psychrometer, a barometer and a thermograph. Stevenson screens may also be known as a cotton region shelter, an instrument shelter, a thermometer shelter, a thermoscreen or a thermometer screen. The use of a standard screen allows temperatures to be compared accurately with those measured in earlier years and at different places. Image File history File linksMetadata Download high resolution version (1232x1632, 631 KB) Exterior shot of a Stevenson screen. ... Image File history File linksMetadata Download high resolution version (1232x1632, 631 KB) Exterior shot of a Stevenson screen. ... Image File history File linksMetadata Download high resolution version (1632x1232, 660 KB) Interior of a Stevenson screen showing (from left to right) the dewcell, wet bulb with wick attached to water supply, dry bulb and dry thermistor. ... Image File history File linksMetadata Download high resolution version (1632x1232, 660 KB) Interior of a Stevenson screen showing (from left to right) the dewcell, wet bulb with wick attached to water supply, dry bulb and dry thermistor. ... Meteorology is the scientific study of the atmosphere that focuses on weather processes and forecasting. ... A technician examines a weather stations anemometer. ... A clinical mercury thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. ... The interior of a Stevenson screen showing a motorized psychrometer Hygrometers are instruments used for measuring humidity. ... Dew cells are instruments used for determining the dew point. ... Hygrometers are instruments used for measuring humidity. ... A barometer is an instrument used to measure atmospheric pressure. ... A thermograph is a recording thermometer. ...

History

It was designed by Thomas Stevenson (1818-1887), a British civil engineer and father of the author Robert Louis Stevenson. Thomas Stevenson, 1880 Thomas Stevenson (1818-1887) was a pioneering lighthouse designer, who designed over thirty lighthouses in and around Scotland, as well as the Stevenson screen used in meteorology. ... A civil engineer is a person who practices civil engineering. ... Robert Louis (Balfour) Stevenson (November 13, 1850–December 3, 1894), was a Scottish novelist, poet and travel writer, and a representative of neo-romanticism in English literature. ...

Composition

The traditional Stevenson screen is a box shape, constructed of wood, in a double-louvered design. However, it is possible to construct a screen using other materials and shapes, such as a triangle. The World Meteorological Organization (WMO) agreed standard for the height of the thermometers is between 1.25 m (4 ft 1 in) and 2 m (6 ft 7 in) above the ground. A louver (or louvre in British English, from French louvert; the open one) is a frame with horizontal and vertical slats, which are angled to admit light and air, but to keep out rain and sun shine. ... WMO flag The World Meteorological Organization (WMO, French: , OMM) is an intergovernmental organization with a membership of 188 Member States and Territories. ...

Size

The interior size of the screen will depend on the number of instruments that are to be used. A single screen may measure 765 mm high by 610 mm wide by 593 mm deep (30.1 in by 24.0 in by 23.3 in) and a double screen 765 mm high by 1050 mm wide x 593 mm deep (30.1 in by 41.3 in by 23.3 in). The unit may be mounted on a wooden stand or a metal pipe.

The top of the screen was originally composed of two asbestos boards with an air space between them. These asbestos boards have generally been replaced by a laminate due to health and safety reasons. The whole screen is painted with several coats of whitewash to reflect radiation and will usually require repainting every two years. For other uses, see Asbestos (disambiguation). ... Laminate flooring Laminated core transformer A laminate is a material constructed by uniting two or more layers of material together. ... Occupational safety and health is the discipline concerned with preserving and protecting human and facility resources in the workplace. ... For other uses, see Radiation (disambiguation). ...

Siting

The siting of the screen is very important to minimise the effects of buildings and trees. Environment Canada for example recommends that the screen be placed at least twice the distance of the height of the object (e.g. 20 m from any tree that is 10 m high, or 40 ft from one 20 ft high). In the northern hemisphere, the door of the screen should always face north so as to prevent direct sunlight on the thermometers. However, in Polar regions with twenty-four hour sunlight the observer must take care to shield the thermometers from the sun and at the same time avoiding a rise in temperature being caused by the observer’s body heat. Environment Canada is the department of the government of Canada with responsibility for coordinating environmental policies and programs as well as preserving and enhancing the natural environment and conservation of wildlife. ... Location of the polar regions Northern Hemisphere permafrost (permanently frozen ground) in purple. ...

A special type of Stevenson screen with an eye on the roof is designed to be used on ship. The unit is hung from the ceiling and remains vertical despite the movement of the vessel.

Future

In some areas the use of single unit automatic weather stations are supplanting the traditional Stevenson screen (and other stand-alone meteorological equipment). An AWS in Antarctica An automatic weather station (AWS) is an automated version of the traditional weather station, either to save human labour or to enable measurements from remote areas. ...

A hemispherical cup anemometer of the type invented in 2000 by John Thomas Romney Robinson An anemometer is a device for measuring the velocity or the pressure of the wind, and is one instrument used in a weather station. ... A barograph is a recording aneroid barometer. ... A barometer is an instrument used to measure atmospheric pressure. ... A ceiling balloon cabinet A fully inflated ceiling balloon Diagram of a filler stand Regulator valve and pressure guages attached to helium cylinder A ceiling balloon is used by meteorologists to determine the height of the base of clouds above ground level during daylight hours. ... Ceiling projector exterior Interior of a ceiling projector Alidade for use with a ceiling projector The ceiling projector or cloud searchlight is used to measure the height of the base of clouds (called the ceiling) above the ground. ... Laser Ceilometer A ceilometer is a device that uses a laser or other light source to determine the height of a cloud base. ... Dark adaptor goggles The Dark adaptor goggles are one of the lesser known tools in the field of meteorology. ... A disdrometer is an instrument used to measure the drop size distribution and velocity of falling precipitation. ... Field mill is a specialized instrument used for measuring the strength of electrical fields in the atmosphere near thunderstrom clouds. ... The interior of a Stevenson screen showing a motorized psychrometer Hygrometers are instruments used for measuring humidity. ... Standard Ice Accretion Indicator (upside down) The Ice Accretion Indicator is an L-shaped piece of aluminium 38 cm (14. ... A FASOR used at the Starfire Optical Range for LIDAR and laser guide star experiments is tuned to the sodium D2a line and used to excite sodium atoms in the upper atmosphere. ... Lightning detector at the Kennedy Space Center in Florida. ... A nephelometer is an instrument for measuring suspended particulates in a liquid. ... Nephoscope is instrument for measuring the altitude, direction, and velocity of movement of clouds. ... Pan evaporation is a measurement that combines or integrates the effects of several climate elements: temperature, humidity, solar radiation, and wind. ... A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface. ... radiosonde with measuring instruments A radiosonde (Sonde is German for probe) is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. ... Standard Rain Gauge Tipping Bucket Rain Gauge Recorder Close up of a Tipping Bucket Rain Gauge Recorder chart A rain gauge (also known as an udometer or a pluviometer[fluviograph] or a cup) is a type of instrument used by meteorologists and hydrologists to gather and measure the amount of... Snow Gauge A snow gauge is a meteorological instrument used to record the depth of snowfall at a specific location. ... SODAR (sonic detection and ranging) - meteorological instrument which priciple of operation is based on sound waves scattering by atmosheric turbulence. ... A solarimeter is a pyranometer used to measure combined direct and diffuse solar radiation. ... A sounding rocket, sometimes called an elevator research rocket, is an instrument-carrying suborbital rocket designed to take measurements and perform scientific experiments during its flight. ... Sunshine Recorders are used to indicate the amount of sunshine at a given location. ... A thermograph is a recording thermometer. ... A clinical mercury thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. ... Rawinsonde weather balloon just after launch. ... Weather radar in Norman, Oklahoma with rainshaft (Source: NOAA) Environment Canada King City (CWKR) weather radar station. ... Weather vane Weather cock Aerovane A weather vane, also called a wind vane, is a movable device attached to an elevated object such as a roof for showing the direction of the wind. ... A windsock is a large, conical, open-ended tube designed to indicate wind direction and relative wind speed. ... A wind profiler is a piece of weather observing equipment that uses sound waves to detect the wind speed and direction at various elevations above the ground. ...

See also

• Thermometer
• Hygrometer

A clinical mercury thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. ... The interior of a Stevenson screen showing a motorized psychrometer Hygrometers are instruments used for measuring humidity. ...

External links

Wikimedia Commons has media related to:

Stevenson screen

• Article - Temperature measurement and the Stevenson screen
• Example of a non-traditional home built Stevenson screen

References