Quantitative estimation of subsurface water and ice content values is critical for the understanding and modeling of permafrost evolution in alpine regions. Geophysical methods permit the assessment of subsurface conditions in a noninvasive and quasicontinuous manner; in particular, the combination of seismic refraction tomography (SRT) and electrical resistivity tomography (ERT) through a petrophysical model can quantitatively estimate ground water and ice content values. For the Hoher Sonnblick study area (3106 m.a.s.l., Austrian Alps), we have investigated the improved estimation of water and ice content values based on SRT, ERT, and ground-penetrating radar data collected in June and October 2019. We solve for the water and ice content values following different approaches, namely, (1) the independent inversion and subsequent transformation of the imaging results to the target parameters through a petrophysical model and (2) the petrophysical joint inversion (PJI) of the data sets. Supported by a synthetic study, we determine that the incorporation of structural and porosity constraints in the PJI allows for an improved quantitative characterization of subsurface conditions. For our measurements at Hoher Sonnblick, the constrained PJI resolves a shallow debris layer characterized by high air content and porosity, on top of a layer with lower porosity corresponding to fractured gneiss, and the bedrock layer with the lowest porosity. For both time steps, we find high water content at the lower end of the investigated area. Substantial variations in the subsurface ice content resolved between June and October 2019 indicate a correlation between the high water content and the meltwater discharge within the debris layer. Our results demonstrate that the constrained PJI permits an improved characterization of subsurface hydrologic parameters in alpine permafrost environments.

中文翻译：

---

通过约束岩石物理联合反演改进对高山永久冻土中冰和水含量的估计：Hoher Sonnblick 案例研究

地下水和冰含量值的定量估计对于高山地区永久冻土演化的理解和建模至关重要。地球物理方法允许以非侵入性和准连续方式评估地下条件；特别是，地震折射层析成像 (SRT) 和电阻率层析成像 (ERT) 通过岩石物理模型相结合，可以定量估计地下水和冰含量值。对于 Hoher Sonnblick 研究区（3106 masl，奥地利阿尔卑斯山），我们研究了基于 SRT、ERT 和 2019 年 6 月和 2019 年 10 月收集的探地雷达数据对水和冰含量值的改进估计。我们求解了水和冰含量值遵循不同的方法，即，(1) 通过岩石物理模型将成像结果独立反演并随后转换为目标参数； (2) 数据集的岩石物理联合反演 (PJI)。在综合研究的支持下，我们确定在 PJI 中加入结构和孔隙度约束可以改进地下条件的定量表征。对于我们在 Hoher Sonnblick 的测量，受约束的 PJI 解析了一个以高空气含量和孔隙度为特征的浅碎屑层，位于孔隙度较低的层之上，对应于断裂的片麻岩，基岩层具有最低的孔隙度。对于这两个时间步长，我们发现调查区域下端的含水量很高。2019 年 6 月至 2019 年 10 月期间解析的地下冰含量的显着变化表明高含水量与碎片层内的融水排放之间存在相关性。我们的结果表明，受约束的 PJI 可以改进高山永久冻土环境中地下水文参数的表征。