A Thermometer screen (Stevenson screen) is an enclosure to shield meteorological instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them. It forms part of a standard weather station. The Stevenson screen holds instruments that may include thermometers (ordinary, maximum/minimum), a hygrometer, a psychrometer, a barometer and a thermograph. Its purpose is to provide a standardised environment in which to measure temperature, humidity, dew point and atmospheric pressure. It is manufactured from teakwood material as dimensions strictly as per IS:5948-1970 specifications. All the four sides are double louvered, roof is double and the floor consists of overlapping boards seperated by an air space. The front door is hinged at
bottom and provided with two chains so that it comes to rest in an approximately horizontal position when opened to its full extent. The screen itself supported on four legs.
Thermometer screen comes with steel stand height such that the floor of thermometer screen will be exactly 117.5 cm above the ground ( at the eye site level). The steel legs are made from MS angles duly coloured & marked with different colour for foundation level.
There are two types of Screen available :
(1) Small size (Single) Thermometer Screen
(Internal size between louvers : 560 x 315 x 412 mm)
Generally it is used for placing separate glass thermometers :
(a) Maximum (b) Minimum (c) Dry Bulb & (d) Wet Bulb thermometers.
There is vertical wooden platform for mounting these four thermometers on it.
(2) Big size (Double) Thermometer Screen (Internal size : 1355 x 355 x 345 mm)
Generally it is used for placing Thermograph, Hygrograph or Barograph inside it.
