Shen Zhichao, Yang Yan, Fu Xiaojing, Adams Kyra H, Biondi Ettore, Zhan Zhongwen
Seismological Laboratory, California Institute of Technology, Pasadena, CA, USA.
Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Nat Commun. 2024 Aug 5;15(1):6432. doi: 10.1038/s41467-024-50690-6.
Vadose zone soil moisture is often considered a pivotal intermediary water reservoir between surface and groundwater in semi-arid regions. Understanding its dynamics in response to changes in meteorologic forcing patterns is essential to enhance the climate resiliency of our ecological and agricultural system. However, the inability to observe high-resolution vadose zone soil moisture dynamics over large spatiotemporal scales hinders quantitative characterization. Here, utilizing pre-existing fiber-optic cables as seismic sensors, we demonstrate a fiber-optic seismic sensing principle to robustly capture vadose zone soil moisture dynamics. Our observations in Ridgecrest, California reveal sub-seasonal precipitation replenishments and a prolonged drought in the vadose zone, consistent with a zero-dimensional hydrological model. Our results suggest a significant water loss of 0.25 m/year through evapotranspiration at our field side, validated by nearby eddy-covariance based measurements. Yet, detailed discrepancies between our observations and modeling highlight the necessity for complementary in-situ validations. Given the escalated regional drought risk under climate change, our findings underscore the promise of fiber-optic seismic sensing to facilitate water resource management in semi-arid regions.
在半干旱地区，包气带土壤水分通常被视为地表水与地下水之间的关键中间水库。了解其对气象强迫模式变化的动态响应，对于增强我们生态和农业系统的气候适应能力至关重要。然而，无法在大时空尺度上观测高分辨率的包气带土壤水分动态，阻碍了定量表征。在此，我们利用现有的光纤电缆作为地震传感器，展示了一种光纤地震传感原理，以稳健地捕捉包气带土壤水分动态。我们在加利福尼亚州里奇克莱斯特的观测结果揭示了包气带的亚季节降水补给和长期干旱，这与零维水文模型一致。我们的结果表明，通过实地蒸散每年有0.25米的显著水分流失，附近基于涡度相关的测量结果验证了这一点。然而，我们的观测与建模之间的详细差异凸显了进行补充原位验证的必要性。鉴于气候变化下区域干旱风险的加剧，我们的研究结果强调了光纤地震传感在促进半干旱地区水资源管理方面的前景。
