Tritium, the radioactive isotope of hydrogen, has been used to understand groundwater recharge processes for decades. The current variation of tritium in the atmosphere is largely attributed to stratospheric production and fall out rates as well as global circulation phenomena controlling the hydrological cycle. Global controls on the variability in atmospheric tritium activity are poorly suited to explain local variation and tritium activities in precipitation are often assumed to be uniform over both local and regional catchments and watersheds. This assumption can result in both over and under estimation of modern recharge within an aquifer when using tritium as the recharge proxy. In order to minimize the inherent prediction residuals associated with tritium based recharge investigations, the variability of tritium in precipitation was modelled from 127 spatial precipitation samples taken over a two year period, combined with a 76 precipitation sample group-set taken over a one year period in a single location. Precipitation events were traced backward in time, from the point of collection, using HYSPLIT modelling to ascertain the origins of moisture content as well as the altitudes of moisture origin reached along the particle track. Tritium activities, collected over a one year period in Paarl, range from 0.45 to 4.16 TU and have a mean of 1.59 TU. Spatial storm events in the Western Cape in 2017 and 2018 had a range from 0 to 2.2 and 0.37 to 3.27 TU, respectively, with mean activities of 1.18 (n = 34) and 1.25 TU (n = 32). Both storm events had similar tritium variability (σ = 0.5 n = 35 and 0.48 n = 32). Regional precipitation events had the largest range of tritium activities (0.55–12.2 TU). Although not all tritium activities can be explained by interrogating the water mass origin, this study suggests that approximately 90% of events can be completely or partially attributed to the origin of the water mass. The variability of tritium, both spatially and temporally, was higher than expected, confirming that when uniform tritium inputs are used, the groundwater system would provide inaccurate modern recharge estimates. Higher spatial resolution of tritium variation in precipitation for a particular region will improve our ability to relate tritium activities in groundwater to local precipitation.

hydrogen是氢的放射性同位素，几十年来一直用于了解地下水的补给过程。大气中of的当前变化在很大程度上归因于平流层的生产和沉降速率以及控制水文循环的全球环流现象。大气中activity活动性变化的全球控制措施不适合用来解释局部变化，并且assumed在降水中的活动通常被认为在地方和区域集水区和流域都是一致的。当使用tri作为补给代理时，该假设可能导致含水层中现代补给的估计过高和估计不足。为了最小化与基于based的补给调查相关的固有预测残差，precipitation的变异性是根据两年内采集的127个空间降水样本和一个地点一年内采集的76个降水样本组模拟的。从收集点开始，使用HYSPLIT模型追溯了降水事件的发生时间，从而确定了水分含量的来源以及沿着颗粒径迹达到的水分高度。一年中在Paarl收集的活动范围为0.45至4.16 TU，平均值为1.59 TU。2017年和2018年，西开普省的空间风暴事件的范围分别为0至2.2和0.37至3.27 TU，平均活动为1.18（n = 34）和1.25 TU（n = 32）。两种风暴事件的similar变化都相似（σ= 0.5 n = 35和0.48 n = 32）。区域降水事件中had的活动范围最大（0.55-12.2 TU）。尽管并非所有tri活动都可以通过询问水团的来源来解释，但这项研究表明，大约90％的事件可以全部或部分归因于水团的来源。tri的时空变异性在空间和时间上都高于预期，这证实了当使用统一的inputs输入时，地下水系统将提供不准确的现代补给估算。特定地区降水中variation变化的更高空间分辨率将提高我们将地下水中tri活动与局部降水联系起来的能力。尽管并非所有tri活动都可以通过询问水团的来源来解释，但这项研究表明，大约90％的事件可以全部或部分归因于水团的来源。tri的时空变异性在空间和时间上都高于预期，这证实了当使用统一的inputs输入时，地下水系统将提供不准确的现代补给估算。特定地区降水中variation变化的更高空间分辨率将提高我们将地下水中tri活动与局部降水联系起来的能力。尽管并非所有tri活动都可以通过询问水团的来源来解释，但这项研究表明，大约90％的事件可以全部或部分归因于水团的来源。tri的时空变异性在空间和时间上都高于预期，这证实了当使用统一的inputs输入时，地下水系统将提供不准确的现代补给估算。特定区域中precipitation变化的更高空间分辨率将提高我们将地下水中ground活动与局部降水联系起来的能力。确认使用统一的tri输入时，地下水系统将提供不准确的现代补给估算。特定地区降水中variation变化的更高空间分辨率将提高我们将地下水中tri活动与局部降水联系起来的能力。确认使用统一的ium输入时，地下水系统将提供不准确的现代补给估算。特定地区降水中variation变化的更高空间分辨率将提高我们将地下水中tri活动与局部降水联系起来的能力。