Accurately interpreting the stable oxygen isotopic composition (δ¹⁸O) of cave drip water is critical to the retrieval of palaeoclimatic information based on the δ¹⁸O records preserved in speleothem calcite. Substantial cave monitoring data sites of interest can make essential contributions. In this study, six speleothem drip water sites and one pool water site were selected for a five‐year (2013–2017) monitoring of O and H stable isotope ratios in Maomaotou Big Cave, Guilin, South China. The results reveal that the drip water δ¹⁸O generally inherits the signals in the precipitation but may lag behind by times ranging from 1 to 6 months. Variations in drip water δ¹⁸O are determined by climatic variables operating over several time scales. At the individual storm‐event scale, drip water δ¹⁸O is a function of rainfall amount, moisture source δ¹⁸O and hydrological processes within the vadose zone. Moisture from nearby Beibu Bay in the northwest of the South China Sea often causes the rainfall and thus drip water to be enriched in ¹⁸O at Maomaotou Cave, for example. Seasonally or annually, the higher amounts of precipitation associated with the occurrence of El Niño events (e.g. in 2015/2016) result in more depleted drip water δ¹⁸O. On the interannual scale, variations of drip water δ¹⁸O are linked to changes in the intensity of the East Asian summer monsoon (EASM), the Southern Oscillation Index (SOI) and the West Pacific Subtropical High (WPSH). An enhanced EASM coupled with La Niña‐like conditions likely results in depleted precipitation δ¹⁸O, as does a stronger WPSH that leads to more rainfall. This study illustrates the importance of understanding these complex and varying external environmental conditions that contribute to δ¹⁸O changes in drip water, when interpreting the palaeoclimatic information contained in speleothems.

中文翻译：

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华南桂林毛毛头大洞滴水δ18O值的个别事件，季节变化和年际变化及其对古气候重建的意义

准确地解释所述稳定氧同位素组成（δ ¹⁸ O）洞穴的滴水是古气候的信息基础上，δ的检索关键^18个ö记录钟乳石方解石保存。感兴趣的大量洞穴监测数据站点可以做出重要贡献。在这项研究中，我们选择了六个蛇麻草滴水站点和一个池水站点，对华南桂林毛毛头大洞穴的O和H稳定同位素比值进行了五年（2013-2017年）监测。该结果表明，该滴水δ ¹⁸ ö通常继承在沉淀的信号，而是可以通过时间从1至6个月落后。在滴水变化δ ¹⁸O由在多个时间尺度上运行的气候变量确定。在各个风暴事件的规模，滴水δ ¹⁸ O是降雨量，湿气源δ的函数^18个渗流区中O和水文过程。例如，南海西北部北部湾附近的水分经常引起降雨，因此滴水在茂茂头洞的¹⁸ O富集。季节性或每年，与厄尔尼诺事件（在例如二千零十六分之二千零十五）结果在更贫滴水δ发生相关联的更高量的沉淀的¹⁸ O.在际尺度，δ滴水的变化¹⁸O与东亚夏季风（EASM），南部涛动指数（SOI）和西太平洋副热带高压（WPSH）强度的变化有关。增强EASM加上拉尼娜样条件在耗尽沉淀δ可能结果¹⁸ O，一样更强的副高，导致更多的降雨。这项研究表明理解这些复杂和变化的，有助于δ外界环境条件的重要性，^18种在滴水Ø变化，解释当包含在洞穴堆积的古气候信息。