Ecohydrological processes in arid and semi-arid regions play a critical role in shaping regional climate dynamics. This study focused on sand dunes and meadows, which are typical ecosystems in the Horqin Sandland, using meteorological, soil, environmental, and eddy covariance (EC) observational data for 10 years (2013–2022). An ecohydrological model (T&C model) was developed for community-scale sandy landscapes to comprehensively simulate ecohydrological processes across different time scales. The results indicated the following: (1) The T&C model effectively simulated the energy, hydrological, and biomass components, including net radiation (Rn), sensible heat flux (H), latent heat flux (LE), soil water content (SWC), gross primary productivity (GPP), and leaf area index (LAI), in sand dunes and meadows, with the R2 values ranging from 0.41 to 0.93 and from 0.66 to 0.92, respectively. The model accurately captured the seasonal dynamics of ecohydrological processes using well-parameterized and portable settings. (2) Energy balance analysis revealed that the energy transport at the dune site was dominated by H from 2013 to 2016, with H/Rn and LE/Rn becoming comparable in 2017–2018 and an increasing proportion of Rn allocated to LE after 2019. At the meadow site, H dominated in the early growing season, whereas LE dominated during the mid-growing season. (3) Water balance analysis showed an average annual rainfall of 395.94 mm. At the dune site, the average annual evapotranspiration was 247.4 mm, with evapotranspiration and deep seepage accounting for over 97 % of the total water consumption. The meadow site had an average annual evapotranspiration of 620.78 mm, and the meadow belongs to groundwater-dependent ecosystems (GDEs). This study provides a theoretical framework and technical support for water resource management and prevention of desertification in desertified regions.

中文翻译：

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半干旱沙丘和草甸生态系统中季节性和年际生态水文过程动态的综合分析

干旱和半干旱地区的生态水文过程在塑造区域气候动态方面起着关键作用。本研究使用为期 10 年（2013-2022 年）的气象、土壤、环境和涡度相关差 （EC） 观测数据，重点关注科尔沁沙地的典型生态系统沙丘和草甸。为社区规模的沙地景观开发了一个生态水文模型（T&C 模型），以全面模拟不同时间尺度的生态水文过程。结果表明：（1）T&C 模型有效地模拟了沙丘和草甸的能量、水文和生物量成分，包括净辐射（Rn）、感热通量（H）、潜热通量（LE）、土壤含水量（SWC）、总初级生产力（GPP）和叶面积指数（LAI），R2 值范围为 0.41—0.93 和 0.66—0.92， 分别。该模型使用参数化良好且可移植的设置准确捕捉了生态水文过程的季节性动态。（2） 能量平衡分析显示，2013—2016 年沙丘场地的能量传输以 H 为主，H/Rn 和 LE/Rn 在 2017—2018 年变得相当，2019 年后分配给 LE 的 Rn 比例增加。在草甸现场，H 在生长季节早期占主导地位，而 LE 在生长季节中期占主导地位。（3） 水平衡分析显示年平均降雨量为 395.94 毫米。在沙丘现场，年平均蒸散量为 247.4 毫米，蒸散和深层渗流占总用水量的 97% 以上。草甸场地的年平均蒸散量为 620.78 mm，属于依赖地下水的生态系统 （GDE）。 本研究为荒漠化地区水资源管理和防治荒漠化提供了理论框架和技术支持。