Cloud Temp: °C
Grass Temp: °C
Soil Temp (10cm): °C
Cloud, Grass & Soil Temps.
Cloud, grass and soil temperature are common temperature measurements recorded by personal weather stations.
Cloud Temperature
The Cloud temperature is obtained using a metal plate held within a small sealed area, with a clear view of the sky. During the day time the plate will heat up. The degree to which is warms will be dependent on the amount of cloud present. At night the effect of blackbody radiation will cool the plate to below ambient when the sky is clear. These measurements allow us to determine the cloud state.
Grass Temperature
Grass temperature is recorded at 5cm above the ground, in-between blades of grass. This location prevents mixing of air due to wind, resulting in a cooler temperature at night and potentially a warmer temperature during the day. The grass temperature is particularly useful for determining whether there is a frost present.
Soil Temperature
The Soil temperature is obtained using temperature sensors at various depths. Soil is a very good insulator, so the temperature stays relatively constant throughout the day. Due to the proximity to the surface, the 10cm deep sensor will show more response to surficial conditions than the sensor placed at 30cm. At depths of approximately 1.5 meters, the insulating properties of the soil mean it takes an extended period for surficial changes in temperature to have an impact. Therefore at this depth it is normally warmer in winter and cooler in summer.