Adsiz Cihat, Skrzypek Grzegorz, McCallum James
General Directorate of Water Management, Republic of Türkiye Ministry of Agriculture and Forestry, Alparslan Türkeş Street No:71, Ankara, Turkiye.
Middle East Technical University, Üniversiteler Mahallesi, Dumlupınar Bulvarı No:1, Çankaya, Ankara 06800, Turkiye.
MethodsX. 2023 Jul 3;11:102265. doi: 10.1016/j.mex.2023.102265. eCollection 2023 Dec.
Accurate estimation of evaporative losses from a water body, using the Craig-Gordon model and the stable hydrogen and oxygen isotope composition of water, requires knowledge of the stable isotope composition of ambient air moisture. This is rarely measured in the field, and it is usually estimated assuming that recent rainfall remains in isotopic equilibrium with atmospheric moisture. However, the ambient air moisture stable isotope composition may vary significantly at different heights above the water body. In this study, we set up outdoor pan evaporation experiments and simultaneously measured the stable isotope composition of ambient moisture in the atmosphere at three different heights. Using these measurements, we calculated evaporative losses, compared them with the observed losses in the pan, and assessed the uncertainty introduced by differences in ambient moisture measurements. Three main steps in the experimental method:•Daily water sampling from the evaporation pan for analysis of stable hydrogen and oxygen isotope compositions.•Recording the stable isotope composition of ambient air moisture at three different heights using the Picarro L2130-i system over a period of experiments.•Calculating evaporative losses from the pan using the Craig-Gordon model and ambient air stable isotope composition measured at three different levels and comparing to the observed losses.
利用克雷格 - 戈登模型以及水体中稳定氢氧同位素组成精确估算水体蒸发损失，需要了解环境空气湿度的稳定同位素组成。这在野外很少测量，通常是在假设近期降雨与大气湿度保持同位素平衡的情况下进行估算。然而，水体上方不同高度处的环境空气湿度稳定同位素组成可能会有显著变化。在本研究中，我们开展了室外蒸发皿蒸发实验，并同时测量了三个不同高度处大气中环境湿度的稳定同位素组成。利用这些测量数据，我们计算了蒸发损失，将其与蒸发皿中观测到的损失进行比较，并评估了环境湿度测量差异所带来的不确定性。实验方法的三个主要步骤：
• 每天从蒸发皿采集水样，分析稳定氢氧同位素组成。
• 在一段实验期间，使用Picarro L2130 - i系统记录三个不同高度处环境空气湿度的稳定同位素组成。
• 利用克雷格 - 戈登模型以及在三个不同高度测量的环境空气稳定同位素组成计算蒸发皿的蒸发损失，并与观测到的损失进行比较。
