I n s t r u m e n t s

a n d

M e t h o d s

Figure 6. Hourly snow depth measurements from Beaver Mountaian, Utah.

depth readings are the result of hourly average data based
ononeminutereadings.Furthermore,thesnowwould
tend to have a greater density and be less subject to wind
scouring anderosion.However, in this situation, the snow
depth also gradually decreases afterthe initial snow fall,
probably as a result of settling andcompaction of the snow.

SUMMARY

The evolution of automatic snow depth measurement sen-
sors based on ultra sonic measurements is discussed.Data
arepresentedfromthetwomostrecentversionsofthe
sensorsandshowhow themeasurement ofsnowdepth
has become more reliable undervarious conditions.Meas-
urement quality indicator numbers are also now available
from the sensorand are discussed.

REFERENCES

Caillet, A., F.G. D'Aillon and I. Zawadzki, 1979. An ultrasound
low power sonar for snow thickness measurements. Proceed-
ingsEasternSnowConference,June1979,AlexandriaBay,
N.Y., pp 108-116.

Goodison,B.E.,R. Wilson,K.Wu andJ.Metcalfe,1984.An
inexpensiveremote snow-depthgauge:anassessment.Pro-
ceedings Western Snow Conference, Sun Valley, Idaho, USA.
April 1984, pp 188-191.

Goodison, B.E., J.R. Metcalfe and R.A. Wilson, 1988. Perform-
anceofaCanadianautomaticsnowdepthsensor.Proceed-
ings,W.M.O.Technical Conference,TECO-88,Leipzig,Ger-
man Democratic Republic.May1988.W.M.O. Geneva,Swit-
zerland.

Gubler,H.1981.Aninexpensiveremotesnowdepthgauge
basedonultrasonicwavereflectionfromthesnowsurface.
Journal of Glaciology,Vol. 27, No.95, pp.157-163.

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