This paper presents and validates a novel root model which accounts for the effect of belowground biomass on dune erosion volumes in XBeach, based on a small-scale wave flume experiment that was translated to a larger scale. A 1D-XBeach model was calibrated by using control runs considering a dune without vegetation. Despite calibration, a general model–data mismatch was observed in terms of overestimated erosion volumes around the waterline. Furthermore, the prediction of overwash had to be induced by increasing the maximum nearshore wave height within the XBeach simulation. Subsequently, applying the root model resulted in a good agreement with the belowground biomass cases, and the consideration of spatially varying rooting depths further improved the results. Predictions of the root model while using locally increased friction coefficients were in line with the aboveground and belowground biomass cases. However, the effect of the root model on the erosion predictions varied among the hydrodynamic conditions, so further improvements are required. Therefore, future research should focus on quantifying the effects of land-based biomass and individual plant characteristics, such as root density, on dune erodibility at large scales, along with their influences on the temporal evolution of dune scarping and avalanching.

中文翻译：

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在大规模数值模拟中考虑陆基生物质对沙丘侵蚀量的影响

本文提出并验证了一种新的根模型，该模型解释了地下生物量对 XBeach 沙丘侵蚀量的影响，基于一个被转换为更大规模的小规模波浪水槽实验。一个 1D-XBeach 模型是通过使用控制运行来校准的，考虑到没有植被的沙丘。尽管进行了校准，但在高估了吃水线周围的侵蚀量方面观察到了一般的模型-数据不匹配。此外，必须通过增加 XBeach 模拟中的最大近岸波高来预测淹没。随后，应用根模型与地下生物量情况非常吻合，并且考虑空间变化的生根深度进一步改善了结果。使用局部增加的摩擦系数时根模型的预测与地上和地下生物量情况一致。然而，根模型对侵蚀预测的影响因水动力条件而异，因此需要进一步改进。因此，未来的研究应侧重于量化陆地生物量和个体植物特征（如根密度）对沙丘可蚀性的大规模影响，以及它们对沙丘陡坡和雪崩时间演变的影响。