Probing Speed and the Snow Scope Probe
One question we often get is whether the probing velocity affects the profile output. It often comes as a surprise that no, penetration rate does not significantly effect the measurement. This is an absolutely critical requirement for the Snow Scope Probe. Because the probe is manually driven into the snowpack, every profile will be driven at a different rate, so being confident that data collected at different rates is comparable is very important.
During the development of the Snow Scope Probe, we drew upon previous studies done on older snow penetrometers (like this research here and here), to gain confidence that at sufficiently high probing speeds, probing velocity would not matter. This theory was proven out once we had operational probes - when probing velocity is between about 0.3m/s and 3m/s, we see very little effect on the output.
The data shown above is an example of profiles taken at different rates in the same snowpack. The velocities (0.6 and 2.1m/s) are just average velocities, as probing speed varies significantly throughout each profile. Each line shows 2 profiles taken with the same probe at different rates, shown individually and then overlapped ontop of each other. Both hardness and depth values align well, demonstrating how velocity is not a critical factor in profile output.
Of course there are limitations eventually to probing speed (exceeding the sample rate of the sensors if you probe too fast (really really fast), or the test time limit (5sec) if you move too slow). However, these limitations are quite easy to stay within, so probing speed shouldn’t be a significant factor in your data collection with the Snow Scope Probe!
