Using light, gas, and pressure to quantify distributed snowpack temperature and interstitial flow dynamics

Snowpack heterogeneity in terms of surface geometry, microstructure, physical and thermal properties constitutes a major challenge for measurements and distributed quantification of various snow variables. We present three innovative and novel techniques for in-situ measurements in the snowpack suitable to characterize small-scale temperature variability and flow dynamics of air and water vapor in the snow pack pore space. (1) Fiber-optic distributed temperature sensing is used for the measurement of temperature in the snow at spatial resolutions of 1m in the horizontal and 0.1m in the vertical direction. Together with collocated density measurements these observations are used for the calculation of distributed conductive heat fluxes. (2) High-frequency fluctuations in wind components are measured and correlated to barometric pressure fluctuations at multiple depths in the snow pack. Results may allow discriminating heat and moisture fluxes within the snow as a result of atmospheric forcing. (3) An in-situ trace gas system has been developed and is proposed for advection-dispersion studies in the snow. An array of sensors installed in the snow measures the spread of a trace gas plume at high temporal resolution.