Measuring Snow Depth. Assignment 5. Due June 8

Discussion: Review the information from the Snow Booklet on measuring snow and precipitation. Review also the information on the Judd Communications depth sensor.

An ultrasonic pulse travels from the transducer (sensor) to a surface and back again. The length of time that the pulse takes can be converted to a distance, when the temperature of the air is known.

Evaluation of sensor beam width. Major obstacle. The beam width of the sensor is reported to be 22 degress. Tape has been placed on the floor to mark the approximate region that should be detected by the sensor. Stand the metal bar at various locations within this area and determine the beam width over which a major obstacle is detected. Does the sensor take the average of the distance to the major obstacle and the rest of the floor?

Evaluation of sensor beam width. minor obstacle. Lay the metal pipe on the floor in the marked area. At what angular distance does the sensor detect the pipe? At what angular distance does the sensor measure the actual width of the pipe?

Impact of wind on sensor. Turn on the fan and record the wind speed.What impact does the wind have measuring the distance to the floor?

Impact of moisture on temperature sensor. Spray some water on the thermistor so that the temperature will be the wet bulb temperature. Turn on the fan. What impact does the change in temperature measured by the sensor have on the distance to the floor? Explain what is happening.

Irregular surface.Play around with the styrofoam and simulate different distributions of snowfall. How does the sensor respond to the different distributions?

Discuss other sources of error in measuring snow depth.