Surface renewal (SR) is a biometeorological technique that uses high-frequency air temperature measurements above a plant canopy to estimate sensible heat flux. The sensible heat flux is then used to estimate latent heat flux as the residual of a surface energy balance equation. SR previously relied on calibration against other methods (e.g., eddy covariance) to obtain accurate measurements of sensible heat flux, and this need for calibration limited the use of SR to research applications. Our group recently showed that compensating for the frequency response characteristics of SR thermocouples causes the calibration factor to converge near the theoretically predicted value of 0.5 (Shapland et al., Agric For Meteorol 189:36–47, 2014). This led to the development of an inexpensive, stand-alone SR system to measure sensible heat flux without the need for calibration, and here we evaluated the SR system in a mature vineyard containing a weighing lysimeter. Vineyard evapotranspiration (ET) measured with SR was strongly and positively correlated with that from the lysimeter, eddy covariance, and a soil water budget approach. ET measured with the various techniques responded similarly to changes in the microclimatic conditions (i.e., day to day variability) and when water was withheld from the entire vineyard for an extended period. A stress index, calculated using reference and actual ET from SR and lysimetry, was correlated to leaf water potential, stomatal conductance, and volumetric soil water content measurements, but some of these relationships were more variable than others. Our results suggest that the new SR method could potentially be used as a low-cost tool to provide growers with field-specific estimates of crop water use and stress for irrigation management in vineyards.

中文翻译：

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比较独立的表面更新方法与称重渗透法和涡流协方差以确定葡萄园蒸发量和葡萄藤水分胁迫

表面更新 (SR) 是一种生物气象学技术，它使用植物冠层上方的高频空气温度测量来估计显热通量。然后使用显热通量来估计潜热通量作为表面能量平衡方程的残差。SR 以前依赖于其他方法（例如涡流协方差）的校准来获得显热通量的准确测量值，而这种校准需求限制了 SR 在研究应用中的使用。我们小组最近表明，对 SR 热电偶的频率响应特性进行补偿会导致校准因子收敛到理论预测值 0.5 附近（Shapland 等人，Agric For Meteorol 189:36–47, 2014）。这导致了一种廉价的、无需校准即可测量显热通量的独立 SR 系统，我们在包含称重蒸渗仪的成熟葡萄园中评估了 SR 系统。用 SR 测量的葡萄园蒸散量 (ET) 与来自蒸渗仪、涡流协方差和土壤水分收支方法的结果呈强正相关。使用各种技术测量的 ET 对小气候条件的变化（即每天的变化）以及整个葡萄园长时间停水时的反应相似。使用参考和实际 ET 计算的压力指数与叶水势、气孔导度和土壤体积含水量测量相关，但其中一些关系比其他关系更易变。