Miscellaneous

What are the components of Stevenson screen?

What are the components of Stevenson screen?

The Stevenson screen holds instruments that may include thermometers (ordinary, maximum/minimum), a hygrometer, a psychrometer, a dewcell, a barometer and a thermograph.

What is the Stevenson screen features?

Stevenson screens are always painted white to better reflect the sun’s rays. The louvered sides allow outside air to flow around the thermometers. At some locations, the airflow is assisted by a psychrometer motor that pumps outside air across the instruments inside.

What is a Stevenson screen in simple words?

A Stevenson screen or instrument shelter is a shelter or an enclosure to meteorological instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them.

Why is Stevenson screen made of wood?

The box is made of wood to prevent absorption and conduction of heat. The four sides of the box are louvered so that the air will still be able to enter and circulate freely.

How is a Stevenson screen used to measure temperature?

To take temperature measurements, thermometers are placed inside instrument enclosures known as a Stevenson screen. A Stevenson screen is basically a box with louvres that allow air to circulate around the thermometer inside while protecting it from outside elements like rain and direct sunlight.

Why is the Stevenson screen made of wood?

Why does a Stevenson screen have a double roof?

It has a double roof which is insulated to create a bad conductor of heat. This is done by creating an air space between the two layers of the roof. This will prevent the box from overheating. The roof is also slanting to avoid the accumulation of water.

Why does the Stevenson screen have metal stands?

It allows for the free circulation of air around the thermometer thus creating a uniform temperature in the screen. The base of the screen is position at about 1.25 –2metres above the ground on a metal stand. Thermometers which indicate the actual temperature are known as ordinary thermometers.

What is the unit of measurement for a Stevenson screen?

It is kept 1.25m/4.1ft (UK standard) above the ground by legs to avoid strong temperature gradients at ground level, has louvred sides to encourage the free passage of air, and is painted white to reflect heat radiation, since what is measured is the temperature of the air in the shade, not of the sunshine.

Why Stevenson screen is facing north?

The front panel is hinged at the bottom to form a door, which allows for maintenance and reading of the thermometers. The door of Stevenson screen is always towards the north in the northern hemisphere and towards the south in the southern hemisphere because direct sunrays also affect mercury.

Why is Stevenson screen raised above the ground?

What are the 3 temperature scales?

The three most common temperature scales are Fahrenheit, Celsius, and Kelvin. Temperature scales are created by identifying two reproducible temperatures. The freezing and boiling temperatures of water at standard atmospheric pressure are commonly used.

Why does the Stevenson screen have a double roof?

Why is the Stevenson screen put on grass?

Its main purpose is to allow the cold and warmth of the temperature to penetrate whilst preventing direct sunshine, wind or rain. This is done by having angled slats around the sides, and a double roof. It is painted white so that it reflects the direct heat of the sun.

What is the height of Stevenson screen from ground level 1 point 1.22 meter 1.35 meter 2.00 meter any height?

Stevenson screen is used for providing shelter for meteorological instruments, particularly wet and dry bulb thermometers. It is kept 1.25 meters above the ground by legs.

Why is the Stevenson screen 1.25 m above ground?

This is because the Sun never shines from the north. It is painted white to reflect incoming radiation from the Sun and is set at a height of 1.25 metres above the ground, so as not to be affected by the Earth’s low-level radiation. The screen should be kept clean from dust and dirt.