TY - Generic T1 - Instantaneous measurements of snowdrifts in small-scale modeling T2 - 62nd Annual Western Snow Conference Y1 - 1994 A1 - Schmidt, R.A. A1 - Jairell, R.L. KW - Computer imaging, Models, Small scale models, Snowdrifts AB -

Side-by-side comparisons of small-scale models in drifting snow can quickly answer questions about efficient drift control. However, measuring snowdrifts simultaneously as they accumulate near paired models requires a faster method than probing each drift with a ruler. We explored computer imaging for a possible alternative. Analyzing photographs of a 'rake' of vertical pinjs pressed in to the drift produced promising results. Usint the method, we compared trapping efficiency of model tree rows with model snow fences, as an example.

JF - 62nd Annual Western Snow Conference T3 - Proceedings of the 62nd Annual Western Snow Conference PB - Western Snow Conference CY - Sante Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1994SchmidtA.pdf ER - TY - Generic T1 - Snowdrifts and the aerodynamic drag on scaled-model shelterbelts T2 - 62nd Annual Western Snow Conference Y1 - 1994 A1 - Schmidt, R.A. A1 - Jairell, R.L. A1 - Tabler, R.D. KW - Aerodynamics, Scale models, Snow drifting AB -

This paper reports the design and initial testing of a device that measures the wind force model windbreaks. Our objective is to improve understanding of the relationship between shelterbelt porosity, aerodynamic drag, and snowdrift formation. Two identical drag-boards allow simultaneous comparison of drag on a model shelterbelt with drag of a snow fence model for which the prototype drag coefficient is known.

JF - 62nd Annual Western Snow Conference T3 - Proceedings of the 62nd Annual Western Snow Conference PB - Western Snow Conference CY - Sante Fe, New Mexico UR - sites/westernsnowconference.org/PDFs/1994SchmidtB.pdf ER - TY - Generic T1 - Sublimation of intercepted snow as a global source of water vapour T2 - 60th Annual Western Snow Conference Y1 - 1992 A1 - Schmidt, R.A. A1 - Troendle, C.A. KW - Global water balance, Redistribution, Sublimation AB - Considering the vapor loss from grains on the snow surface produced a model to predict the sublimation rate of snow intercepted on conifer branches. Experiments to test this model showed that the controlling environmental factors, temperature, humidity, radiation, and wind speed, were properly accounted for. These results, combined with other experiments on the redistribution of snow by wind, show that most of the water increase associated with timber harvest in snow country may be attributed to reduced sublimation losses. If so, then up to a third of snowfall may return directly to the atmosphere from forest canopies. The paper compares the significance of timber harvest with climate change in influencing the magnitude of this component of the global water balance. JF - 60th Annual Western Snow Conference T3 - Proceedings of the 60th Annual Western Snow Conference PB - Western Snow Conference CY - Jackson Hole, Wyoming UR - sites/westernsnowconference.org/PDFs/1992Schmidt.pdf ER - TY - Generic T1 - Measuring snow interception and loss from an artificial conifer T2 - 56th Annual Western Snow Conference Y1 - 1988 A1 - Schmidt, R.A. A1 - Jairell, R.L. A1 - Pomeroy, J.W. KW - Snow, Snow evaporation, Snow interception AB - A 1-m high artificial christmas tree and the snow held on its branches is weighed by an electronic balance that transfers values to a computer in a nearby mobile laboratory. An insulated box provides a stable environment for the balance, and plastic bushings in a metal tripod gave low-friction support to the vertical shaft supporting the tree. Measurements are sufficiently accurate that evaporation of intercepted snow could be correlated with environmental factors during periods as short as 10-15 min, for mid-winter conditions in a lodgepole pine stand. JF - 56th Annual Western Snow Conference T3 - Proceedings of the 56th Annual Western Snow Conference PB - Western Snow Conference CY - Kalispell, Montana UR - sites/westernsnowconference.org/PDFs/1988Schmidt.pdf ER - TY - Generic T1 - Swiss improvements of the FMCW radar for snow measurements T2 - 52nd Annual Western Snow Conference Y1 - 1984 A1 - Schmidt, R.A. A1 - Gubler, H. A1 - Hiller, M. KW - FMCW radar, Snow measurements, Snow water equivalent, Snowpack AB - Low-power electronic circuits that produce greater sweep stability, improve signal-to-noise ratio, and permit remote operation from batteries have enhanced snow measurements with a swept-frequency, X-band radar. If snow depth is determined with 1% accuracy, the system predicts water equivalent of a dry snowpack within 5% of gravimetric measurements. Snow depths up to 6 m, determined by radar, compared well with probed depths. When density was estimated from an empirical depth-density relationship. JF - 52nd Annual Western Snow Conference T3 - Proceedings of the 52nd Annual Western Snow Conference PB - Western Snow Conference CY - Sun Valley, Idaho UR - sites/westernsnowconference.org/PDFs/1984Schmidt.pdf ER - TY - Generic T1 - A new device for sampling mass flux of blowing snow T2 - 50th Annual Western Snow Conference Y1 - 1982 A1 - Schmidt, R.A. A1 - Tabler, R.D. A1 - Jairell, R.L. KW - Blowing snow, Hydrologic measurements, Instruments, Snow, Snowdrift AB - Snow blown through a sharp-edged frame, 5 cm wide and extending 50 cm above the ice on a frozen lake, is trapped by a porous fabric bag. Wind shakes the snow from the bag into a 100-liter container in a steel casement beneath the surface, where it is weighed by an electronic balance. Connection to a remote computer allows 15 second readings of drift flux. The device provided excellent measurements during 236 runs of 5-min duration, in blizzards with transport rates as high as 300 g/m-s. JF - 50th Annual Western Snow Conference T3 - Proceedings of the 50th Annual Western Snow Conference PB - Western Snow Conference CY - Reno, Nevada UR - sites/westernsnowconference.org/PDFs/1982Schmidt.pdf ER - TY - Generic T1 - Predicting deposition of blowing snow in trenches from particle trajectories T2 - 49th Annual Western Snow Conference Y1 - 1981 A1 - Schmidt, R.A. A1 - Randolph, K.L. KW - Blowing snow, Contour trenches, Snow drifts, Snow trapping efficiency AB - The paper presents a computational procedure that estimates the location of deposition behind backward-facing steps, assuming blowing snow particles have streamwise velocities equal to the wind speed and vertical velocities equal to partical fall velocities. Results suggest that the efficiency with which snow is trapped in contour trenches is independent of height, for the range 1 to 2 m. Predicted efficiency is much smaller if the windward slope is uphill approaching the trench. JF - 49th Annual Western Snow Conference T3 - Proceedings of the 49th Annual Western Snow Conference PB - Western Snow Conference CY - St. George, Utah UR - sites/westernsnowconference.org/PDFs/1981Schmidt.pdf ER -