I n s t r u m e n t s

a n d

M e t h o d s

AutomaticMonitoringofSnowDepth

Cl audeLabine

CampbellScientific Canada (Corp.),11564 149 Street,Edmonton, Alberta, T5M 1W7.

Tel:(403) 454-2505, Fax: (403) 454-2655

Email: campsci@freenet.edmonton.ab.ca

Key Words:Snow depth,measurement,automatic

ABSTRACT

This presentation is a review of the evolution of the meas-
urement of snow depth using an acoustic(ultra sonic) sen-
sor.OriginallydevelopedwithintheHydrometeorology
Division of the Canadian AtmosphericEnvironment Serv-
ice,the sensorhas undergone a series of design changes.
Although the transducer has remainedthe same, the pack-
agingand electronicdesign ofthesensoristodayquite
differentthan theoriginalsensor.Data fromthree sites
will be presented toassistin showing the evolution and
performance ofthe sensor.The data willshowhow the
measurements producedby the sensor have improved and
stabilized.

INTRODUCTION

Intheearly1980's,theAtmospheric EnvironmentServ-
icesofEnvironmentCanadarecognized theneed for"a
reliable,low costautomatic snowdepth sensor" and de-
veloped this sensor (Goodison et al. 1984, Goodison et al.,
1988).The ultra sonic wave reflection in airwas used as
themethodformeasuringsnowdepth,a techniqueini-
tially presented by Caillet et al.(1979),and Gubler (1981).
The sensordetermines the distance to a target by sending
out ultrasonic sound pulses and listening for the returning
echoes from a target.The time from transmit to the return
oftheechoisthebasisforobtainingthedistance
measurement. Once theinitialdesignandverificationwere
completed, a prototype sensor andtechnologywas licensed
toCampbellScientific(Canada)Corp.(CSCC)for

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