Item: Measuring Snow Surface Temperature: Why, why Not, and How?
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Title: Measuring Snow Surface Temperature: Why, why Not, and How?
Proceedings: International Snow Science Workshop 2016 Proceedings, Breckenridge, CO, USA
Authors:
- Bruce Jamieson [ University of Calgary, Calgary, AB, Canada ] [ Snowline Associates Ltd, Calgary, AB, Canada ]
- Michael Schirmer [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
Date: 2016-10-02
Abstract: Avalanche mitigation programs measures snow surface temperature, Tss, for up to three objectives: 1) to infer near surface faceting (NSF) from Tss and the snow temperature 10 cm or 20 cm below the surface; 2) to measure change in the snow surface temperature over time (e.g. days) usually at study plots; 3) to determine the point-in-time surface temperature. We review the surface properties of snow and the energy exchange at the snow surface and identify the low albedo of contact thermometers as problematic for measuring snow surface temperature. Using field studies with contact thermometers, hand-held IR thermometers and an IR camera, we show that a contact thermometer on a shaded part of the snow surface can be up to 6°C above the surface temperature. While hand-held IR thermometers are promising for measuring Tss, some units are more accurate than others and some units are slow to adjust to the ambient temperature. Since the true snow surface temperature varies widely within hours and the near surface temperature gradient usually reverses twice per day, a point-in-time measurement of the surface temperature – even with an accurate handheld IR thermometer - is less indicative of NSF than observations of the sky cover. We recommend observations or measurement methods for each of the three objectives of avalanche mitigation programs
Language of Article: English
Presenters:
Keywords: surface temperature measurement, snow surface, infrared thermometers, contact thermometers, temperature gradient, near surface faceting
Page Number(s): 254-261
Subjects: snow surface temperature temperature gradient near surface facets
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Digital Abstract Not Available
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