In this study, a two-year experiment in an irrigated vineyard was conducted to investigate the variations in energy fluxes (net radiation, ; latent heat flux, LE; sensible heat flux, ; and soil heat flux, ) and quantify the influence of arid advection and environmental factors (vapor pressure deficit (VPD), , air temperature, wind speed, precipitation, and volumetric soil water content) on energy partitioning in arid Northwest China. For the diurnal variation, the peak values of the energy fluxes appeared at approximately 14:00, except for (which appeared at approximately 16:00). LE was the main consumer of daytime (>0) energy during the growing season (average LE/(–) was 87% and 89% in the two years), even during the shooting and leaf-fall stages. Arid advection, which affects energy partitioning mainly by increasing atmospheric evaporative demand and providing heat energy, contributed 6–60% and 1–56% of the average daytime LE during the two growing seasons, especially at the fruiting stage. Moreover, advection accounted for more than half of average daytime energy imbalances. We found that the arid advection induced by irrigation could be attenuated by selecting a reasonable irrigation time. According to the structural equation modeling (SEM) analysis, had the strongest direct and positive regulation effect on LE at the half-hourly and daily scales, indicating that LE was limited by energy rather than water in the study area. The influence of on LE gradually weakened with an increase in the time scale, whereas the effect of VPD increased, which may have been due to the smaller time-lag effect between VPD and LE. The diurnal variations in LE at approximately 08:00–19:30 and 19:30–08:00 were mainly controlled by the direct positive effects of and VPD, respectively. The results obtained in this study will provide a better understanding of surface processes and help improve water resource management in arid agricultural areas.

中文翻译：

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西北干旱地区灌溉葡萄园能量分配：变化特征、影响程度及影响因素路径

在这项研究中，在灌溉葡萄园中进行了为期两年的实验，以研究能量通量的变化（净辐射；潜热通量，LE；感热通量；和土壤热通量），并量化干旱的影响。平流和环境因素（水汽压差（VPD）、气温、风速、降水量和土壤体积含水量）对西北干旱地区能量分配的影响。对于日变化，能量通量的峰值出现在大约14:00，除了（出现在大约16:00）。 LE 是生长季节白天 (>0) 能量的主要消耗者（两年平均 LE/(–) 分别为 87% 和 89%），甚至在抽芽和落叶阶段也是如此。干旱平流主要通过增加大气蒸发需求和提供热能来影响能量分配，在两个生长季，特别是在结果期，贡献了平均白天LE的6%~60%和1%~56%。此外，平均白天能量失衡的一半以上是由平流造成的。我们发现，通过选择合理的灌溉时间可以减弱灌溉引起的干旱平流。根据结构方程模型（SEM）分析，在半小时和日尺度上，对LE具有最强的直接和正向调节作用，表明研究区LE受到能量而非水的限制。随着时间尺度的增加， LE 对 LE 的影响逐渐减弱，而 VPD 的影响逐渐增强，这可能是由于 VPD 和 LE 之间的时滞效应较小。约 08:00–19:30 和 19:30–08:00 LE 的日变化主要分别受 和 VPD 的直接正效应控制。本研究获得的结果将有助于更好地了解地表过程，并有助于改善干旱农业地区的水资源管理。