Snow depth sensor
The snow depth sensor is a measuring device for determining the height of a snow cover .
Formation of snow cover
The detection of the snow depth is an important parameter for the detection of the snow cover in the terrain. Their training is subject to strong spatial and temporal fluctuations. Influencing factors are the development of the snow cover under the influence of other weather conditions (air temperature, wind, radiation ...), the nature of the terrain and the spatial distribution of precipitation in an area. Due to these factors, the selection of the suitable measuring point is largely responsible for whether it is representative of a location.
Measuring principle and accuracy
Ultrasonic snow depth sensor
The measuring principle of the sensor is mostly based on the transit time measurement of an ultrasonic pulse . The sensor sends several high-energy impulses to the snowpack and then receives the signals it reflects. The sensor calculates the current snow depth based on the required transit time of the ultrasonic signals. The air temperature has an enormous influence on the transit time of the ultrasonic pulse. The snow depth sensor should therefore have temperature compensation. This includes the influence of the air temperature on the transit time of the ultrasonic signals in the calculation of the snow depth. It should also be noted that the sensor has an intelligent processing of measured values that filters snow or rain precipitation in order to eliminate interfering reflections , so that reliable measurement is guaranteed even in bad weather.
Laser snow depth sensor
Another method of measuring snow depths is based on laser distance measurement . In comparison to the ultrasonic measurement, this is not temperature-dependent.
Selection of the measuring point
The correct selection and placement of the measuring point is of great importance. The measuring field to be recorded should be as flat as possible, protected from the wind and safe from avalanches. Steep slopes, hollows, edges of terrain or large rocks in the immediate vicinity of the measuring point should be avoided. A steep incline of the snow field harbors the risk that the snow cover can slide and thus the measurement result is falsified. To ensure a perfect measurement, the sensor must be aligned parallel to the ground. Slight slopes of the ground can be compensated for by correctly aligning the sensor using the bracket supplied. Furthermore, the expected snow depth at the measuring point should be estimated in advance in order to ensure the appropriate mounting height of the sensor.
Web links
- The problem of determining the snow depth , topic of the day on Wetterdienst.de
- Characteristics and circuits of an SHS