Karst systems are characterized by a high subsurface heterogeneity, and their complex recharge processes are difficult to characterize. Experimental methods to study karst systems mostly focus on analysing the entire aquifer. Despite their important role in recharge processes, the soil and epikarst receive limited attention, and the few available studies were performed at sites of similar latitudes. In this paper, we describe a new monitoring network that allows for the improvement of the understanding of soil and epikarst processes by including different karst systems with different land-cover types in different climate regions. Here, we present preliminary data form the network and elaborate on their potential to answer research questions about the role of soil and epikarst on karstic water flow and storage. The network measures soil moisture at multiple points and depths to understand the partitioning of rainfall into infiltration, evapotranspiration, and groundwater recharge processes. We installed soil moisture probes at five different climate regions: Puerto Rico (tropical), Spain (Mediterranean), the United Kingdom (humid oceanic), Germany (humid mountainous), and Australia (dry semi-arid). At each of the five sites, we defined two 20 m×20 m plots with different land-use types (forest and grassland). At each plot, 15 soil moisture profiles were randomly selected and probes at different depths from the topsoil to the epikarst (in total over 400 soil moisture probes) were installed. Covering the spatio-temporal variability of flow processes through a large number of profiles, our monitoring network will allow researchers to develop a new conceptual understanding of evapotranspiration and groundwater recharge processes in karst regions across different climate regions and land-use types, and this will provide the base for quantitative assessment with physically based modelling approaches in the future.

中文翻译：

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一个土壤水分监测网络，用于表征全球五个代表性地点的岩溶补给量和蒸散量

岩溶系统的特征是地下非均质性高，其复杂的补给过程难以表征。研究岩溶系统的实验方法主要集中在分析整个含水层。尽管它们在补给过程中起着重要作用，但土壤和表层岩溶受到的关注有限，并且很少有研究是在相似纬度的地点进行的。在本文中，我们描述了一个新的监测网络，该网络通过包含不同气候区域中具有不同土地覆盖类型的不同喀斯特系统，可以增进对土壤和表层岩溶过程的了解。在这里，我们通过网络提供了初步数据，并详细阐述了其潜力，可以回答有关土壤和表层岩溶在岩溶水流动和存储中的作用的研究问题。该网络在多个点和深度测量土壤湿度，以了解降雨在渗透，蒸散和地下水补给过程中的分配。我们在五个不同的气候区域安装了土壤湿度探测器：波多黎各（热带），西班牙（地中海），英国（潮湿的海洋），德国（潮湿的山区）和澳大利亚（干燥的半干旱地区）。在这五个站点中，我们分别定义了两个不同土地利用类型（森林和草地）的20 m×20 m地块。在每个样地中，随机选择15种土壤水分剖面，并安装了从表土到表层岩溶不同深度的探针（总共超过400个土壤水分探针）。我们的监测网络将通过大量的资料涵盖流量过程的时空变化，我们的监测网络将使研究人员对不同气候区域和土地利用类型的喀斯特地区的蒸散和地下水补给过程有了新的概念性理解，这将为将来使用基于物理的建模方法进行定量评估提供基础。