The process-based Biome-BGC (Biome Biogeochemical Cycles) model is widely used to simulate the fluxes of carbon and water of terrestrial ecosystems. While exhibiting excellent performance in simulating carbon cycle processes, this model provides a relatively simple simulation of the water cycle processes, particularly in canopy interception, which may result in significant errors in evapotranspiration (ET) and soil moisture estimations. This study initially refined the temporal scale of the original Biome-BGC model from a daily scale to an hourly scale, and then incorporated a theoretical interception module into the hourly-scale model for correcting canopy interception algorithm, to enhance the accuracy of hydrological processes simulations. The modified model was tested using the half-hourly observed meteorological and eddy covariance flux data at the Qianyanzhou subtropical coniferous forest site. In comparison with the original daily-scale model, simulations from the hourly-scale model showed better agreement with measurements at Qianyanzhou forest site, with 30.61 % and 40.92 % lower annual average gross primary productivity (GPP) and ET simulations. Although the accuracy of GPP and ET simulations did not show a significant improvement after canopy interception correction, it notably enhanced the accuracy of canopy interception and soil moisture simulations. The canopy interception rates were 55.8 % and 44.1 % for the original daily-scale and hourly-scale model, obviously overstimated compared with canopy correction simulation (31.1 %), leading to a significant underestimation of runoff. The canopy interception and runoff simulations after interception correction were proven relatively more reasonable. Additionally, the coefficient of determination () for measured vs simulated soil water content (SWC) were 0.38, 0.51 and 0.60 for the original daily-scale, hourly-scale, and canopy interception correction simulations respectively, with a notable improvement in accuracy. This study suggested that improvements in temporal scale and canopy interception for process-based biogeochemical model can provide a better understanding of the carbon and water exchanges in response to instantaneous meteorological conditions and support improved water resource management.

中文翻译：

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生物地球化学模型中改进的冠层拦截方案，用于精确模拟亚热带针叶林碳和水通量


基于过程的Biome-BGC（Biome生物地球化学循环）模型广泛用于模拟陆地生态系统的碳和水通量。该模型在模拟碳循环过程方面表现出优异的性能，但对水循环过程的模拟相对简单，特别是在冠层拦截方面，这可能会导致蒸散量（ET）和土壤湿度估计出现显着误差。本研究首先将原始Biome-BGC模型的时间尺度从日尺度细化为小时尺度，然后在小时尺度模型中引入理论拦截模块来修正冠层拦截算法，以提高水文过程模拟的准确性。利用千烟洲亚热带针叶林场每半小时观测的气象和涡流协方差通量数据对修改后的模型进行了测试。与原始的日尺度模型相比，小时尺度模型的模拟结果与千烟洲林区实测结果吻合较好，年平均总初级生产力（GPP）和蒸散量模拟值分别降低了30.61%和40.92%。虽然冠层拦截校正后GPP和ET模拟的精度没有表现出明显的改善，但它显着提高了冠层拦截和土壤湿度模拟的精度。原始日尺度和小时尺度模型的冠层拦截率为55.8%和44.1%，与冠层修正模拟（31.1%）相比明显高估，导致径流明显低估。截流修正后的冠层截流和径流模拟相对更为合理。 此外，原始日尺度、小时尺度和冠层截留修正模拟的实测土壤含水量与模拟土壤含水量（SWC）的决定系数分别为0.38、0.51和0.60，精度显着提高。这项研究表明，基于过程的生物地球化学模型的时间尺度和冠层拦截的改进可以更好地了解响应瞬时气象条件的碳和水交换，并支持改进水资源管理。