Sampling of a snowstorm by a 2D-C probe with and without aspiration

A 2D-C probe was mounted on the front of a truck for operation in a horizontal orientation, as on an aircraft, and also in a vertical orientation using an aspirator. A snowstorm with calm conditions was sampled by alternatively driving the truck through the snow, using a calibrated anemometer to control the strobe rate, and then sampling with an aspirator while parked. The concentration measurements made by using an aspirator were similar to 2.4 times larger than those made by using the standard aircraft orientation mode. There was little size dependence in this factor for the dendrite /aggregate snow sampled. It is not yet known what causes the aspirator concentration measurements to be larger than those from other techniques.