The Stevenson's screen is raised about one meter above the ground in order to avoid

The Stevenson's screen is a box used to house weather instruments that measure temperature, humidity, and other meteorological variables. It is raised about one meter above the ground to avoid the heat from the ground. When the screen is placed on the ground, it can absorb and radiate heat from the ground, which can affect the accuracy of temperature measurements. By raising it one meter above the ground, the screen is more exposed to the free atmosphere and less affected by the heat from the ground. Additionally, raising the screen helps to reduce the impact of raindrops entering the instruments during heavy rainfall. The height also helps to avoid the effects of nearby trees and other obstacles that could affect wind flow around the instruments and affect the measurements. Therefore, the main reason for raising the Stevenson's screen one meter above the ground is to ensure that the weather instruments inside are measuring the temperature and other meteorological variables accurately and without interference from external factors.