how to measured air temperature?

Question

because if the thermometer are put near the surface,. it will show ground temperature.
where do i put the thermometer?
and what the height to place it?

Answer 1

The measurement of true air temperature is a matter of extreme difficulty owing to the fact that a thermometer freely exposed to the air is affected by radiation of heat to and from sorrounding objects in addition to the direct radiation from the sun.It is therefore necessary to keep the thermometer in some form of enclosure or screen which will allow the air to circulate freely past the bulb of the thermometer and at the same time shield the thermometer from the radiation emitted by its sorroundings.
The usual form of screen,Known as Stevenson's screen is a wooden box painted white with louvered sides.Now the air can freely circulate inside and external radiation also is prevented.The box is raised four feet above the ground and is erected in such a way as to open towards the north in the Northern hemisphere and towards south in the southern hemisphere.This is because, the apparent movement of the sun is limited by 23.5 degrees N and S latitudes and there is less chance of the themometer bulbs getting heated by the direct sunrays while opening the door.

Answer 2

There are specific rules and regulations about the location of the thermometers meant to measure the maximum and minimum temperature and relative humidity (like the met. office). Six's maximum and minimum thermometer (one dry bulb and another wet bulb type) are used. They are kept in shade and at a height of about 5 - 6 feet. There are other conditions too.