Among the following, which thermometer is not installed in an agro-meteorology observatory?
Show Hint
Stevenson screen thermometers must measure air temperature indirectly without direct contact with solar radiation or the ground. Hand-held sensors like IR thermometers are diagnostic field tools rather than stationary observatory station instruments.
Step 1: Understanding the Concept:
Agro-meteorological observatories house standard, permanently installed instruments inside a Stevenson screen to measure ambient climatic factors under standardized, shade-protected conditions. Step 3: Detailed Explanation:
Let us review the listed instruments:
1. Maximum temperature thermometer: A liquid-in-glass (mercury) thermometer permanently installed horizontally in a Stevenson screen to record daily peak air temperature.
2. Minimum temperature thermometer: A liquid-in-glass (alcohol) thermometer permanently installed horizontally in a Stevenson screen to record the lowest temperature, usually at dawn.
3. Wet bulb thermometer: Part of a psychrometer setup permanently installed in the Stevenson screen to measure the cooling effect of evaporation, which determines relative humidity.
4. Infrared (IR) thermometer: A portable, hand-held, non-contact sensor used directly in fields to measure crop canopy temperature or soil surface temperature. It is a remote sensing tool and is not installed in a standard Stevenson screen. Step 4: Final Answer:
The correct option is 4, which corresponds to IR thermometer.
