Attenuation of wind-induced pressure perturbations in alpine snow

Windpumping has been identified as a process that could potentially enhance sublimation of surface snow at high forcing frequency and spawn air movement deeper in firn at lower frequencies. We performed an experiment to examine the relationship between high-frequency wind and pressure measurements within the top meter of an alpine snowpack and compared experimental results with two theoretical predictions. We find that both theoretical predictions underestimate high-frequency perturbation pressure attenuation with depth in the near-surface snowpack and the discrepancy between theory and measurement increases with perturbation pressure frequency. The impact of this result for near-surface snow is that potential enhanced sublimation will occur over a shallower snow depth than these two theories predict. Correspondingly, interstitial air mixing at depth in firn will be driven by lower frequencies than these two theories predict. While direct measurement of these energy-rich lower frequencies is beyond the scope of this paper, stationary pressure measurements validate the presence of a pressure field that could drive near-surface circulation.

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风力抽吸作用已被确认为一种在强强迫频率下可能增强地表雪升华的过程，并在较低频率下激发更深层雪层中的空气流动。本研究旨在探讨高频风速与高山区雪层顶部一米范围内的压力测量之间的关系，并将实验结果与两种理论预测进行了比较。研究发现，这两种理论预测均低估了近地表雪层中高频扰动压力的深度衰减，且理论与测量之间的差异随着扰动压力频率的增加而增大。对于近地表雪层而言，这一结果意味着潜在的增强升华将在比这两种理论预测的更浅的雪深度处发生。相应地，深层雪层中的孔隙空气混合将由比这两种理论预测的更低频率驱动。尽管直接测量这些富含能量的低频率超出了本论文的研究范围，但静止压力测量验证了存在一个可能驱动近地表循环的压力场。

原始项目数据可通过联系 [e-mail] 获取。