Altocumulus Lenticularis (Cm4) clouds photographed over the Moray Firth on the 30 th August 2016
How does the Aurora Cloud Sensor work? This system works by comparing the cloud base temperature with the air temperature 2m above ground. Under clear skies the system senses the upper atmosphere temperature (which is very cold). However if the sky is cloudy the base temperature is only slightly colder than the air temperature. The system comprises of sensors for cloud, rain, light and sensor temperature. The Cloud Sensor III also incorporates heaters to prevent false alerts due to dew / frost / light snow.
Cloud base height shown takes account of the station elevation at 18 meters (59ft) above MSL.