SSF FORCING - Temporal dynamics and land use effects of SSF - Irrigation experiments combined with ERT measurements

在样地尺度上对不同强迫对地下暴雨流的影响进行实验和数值评估，为斜坡和流域尺度上的地下暴雨流模拟提供支持。该图被视为在这些不同尺度上评估SFF的最小公分母。我们讨论了不同的初始和边界条件，以及不同的土壤和土地利用特征，这些都会影响SFF的产生和时间动态。目的是推导阈值，从而参数化来描述过程动力学。我们将通过分析人工降雨模拟（ARS）和本项目内进行的ARS的现有数据来达到这些目标。计划进行的测试将包括定量流量测量以及对四个具有不同特征的研究集水区的流量和状态进行定性评估。具体的研究问题包括：(1)如何在样地尺度上检测SSF垂直和横向流动分量的通量和路径？哪些示踪剂和测量方法（如TDR、稳定同位素、ERT）可用于识别它们？(2)事件间动态如何影响地表径流与土壤土壤融资量的比例？(3)土地利用和覆被的季节变化如何影响可持续森林资源？前提条件的时间动态如何影响SSF？(4)在样地尺度上启动SSF的阈值是什么？场地和集水区之间的阈值（与其他集水区/场地的链接）的可变性和可转移性如何？(5)在自然降雨期间和之后，利用稳定水同位素或ERT检测优先SSF的空间变异性的效果如何？什么空间范围（面积/流量长度）对可持续水动力有贡献？工作计划的重点是SSF的驱动力和对SSF时间动态影响的识别，结合创新的喷洒实验和涉及不同示踪剂方法的永久性和基于运动的测量。WP1和WP2包含地块尺度的洒水试验，计划并应用于沟槽地块，研究降雨、径流或地下流入等不同初始和边界条件的影响。灌溉试验将结合应用不同的示踪剂方法（项目A、C、D、F）、安装土壤湿度测量（项目A、H）、ERT测量（项目A、B）和超高频雷达(等。项目A)在所有四个测试地点。WP3处理分析、评估和不确定性评估，将WP 1和WP 2的输出结合起来，以建立强迫、边界条件和SSF动力学之间的联系。WP4解决了在样地尺度和小集水区水平处理驱动力分布的建模区域化问题，以便更好地确定用于改进建模的参数设置。在WP 5中，使用不同复杂度的模型对样地尺度上的过程进行数值模拟。

We are focusing on the experimental and numerical assessment of the effects of different forcing on subsurface stormflow (SSF) at the plot scale, which will support the modeling of SSF on the hillslope and catchment scales. The plot is seen as the least common denominator to assess SFF over these different scales. We address varying initial and boundary conditions as well as different soil and land use characteristics which affect the generation and the temporal dynamics of SFF.Aims are to derive thresholds and consequently a parameterization to describe the process dynamics. We will reach these aims by means of analysis of pre-existing data from artificial rainfall simulations (ARS) and from ARS conducted within this project. The planned tests will comprise quantitative flow measurements as well as qualitative assessment of fluxes and states in four research catchments with different characteristics.Specific research questions include: (1) How can fluxes and pathways of vertical and lateral SSF flow components be detected at the plot scale? Which tracers and measurement methods (e.g. TDR, stable isotopes, ERT) can be used to identify them? (2) How are inter-event dynamics affecting the proportion between surface runoff and SSF? (3) How are seasonal changes of land use and cover affecting SSF? How do temporal dynamics of precondition affect SSF? (4) What are the thresholds to initiate SSF on the plot scale? How variable and transferable are thresholds among sites and catchments (link to other catchments/sites)? (5) How well can we detect the spatial variability of preferential SSF using stable water isotopes or ERT during and after natural rainfall events? What is the spatial extent (area/flow length) contributing to SSF?The work program focuses on the driving forces of SSF and the identification of impacts on SSF temporal dynamics combining innovative sprinkling experiments with permanent, and campaign-based measurements involving different tracer methods. WP1 and WP2 contain the plot scale sprinkling experiments, planned and applied at the trenched plots studying the effect of different initial and boundary conditions such as rainfall, runon or subsurface inflow. The irrigation experiments will be combined with the application of different tracer methods (projects A, C, D, F), installed soil moisture measurements (projects A, H), ERT measurements (projects A, B), and UHF radar (ext. coop. project A) in all four test sites. WP3 deals with the analysis, evaluation and the uncertainty assessment, were the outputs of WP 1 and 2 are combined to establish links between forcing, boundary conditions and SSF dynamics. WP4 addresses regionalization for modelling dealing with the distribution of driving forces among plot scales and at sub catchment level, in order to better identify parameter settings used for an improved modelling. In WP 5, numerical modeling of the processes on the plot scale is performed with models of different complexity.