ABSTRACT The mid-latitude coastal area at the western South-Atlantic out of the tropics is under the combined effect of different atmospheric circulation patterns at different temporal scales, which can be shown by the isotope composition of precipitation. This pattern effect is more changing and complex than that for the well-studied tropical areas, the isotope studies being an interesting proxy for identifying major processes. This study is focused on the isotope composition of precipitation at a mid-latitude zone, in the western South-Atlantic coastal area of Argentina. δ18O and d-excess were analysed in a data series of 14 years, obtained from the integration of three neighbouring rain collectors at 38°S. A seasonality is observed in both parameters, but with some differences in the extreme months. δ18O showed a seasonality according to the temperature effect, but with a displacement of high values to spring months. Significant linear links between δ18O and Southern Annular Mode (SAM) index and Southern Oscillation Index (SOI) were recognised for the summer and spring seasons, respectively.

中文翻译：

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西南大西洋地区中纬度降水中δ18O和d-excess的大气约束

摘要 热带外南大西洋中纬度沿海地区处于不同时间尺度的不同大气环流模式的综合作用下，这可以通过降水的同位素组成来表现。这种模式效应比经过充分研究的热带地区更具变化性和复杂性，同位素研究是识别主要过程的有趣代表。这项研究的重点是阿根廷南大西洋西部沿海地区中纬度地区降水的同位素组成。δ18O 和 d-excess 在 14 年的数据系列中进行了分析，这些数据是从 38°S 的三个相邻雨水收集器的整合中获得的。在两个参数中都观察到了季节性，但在极端月份存在一些差异。δ18O 根据温度效应表现出季节性，但在春季月份有较高值的​​位移。δ18O 与南方环模 (SAM) 指数和南方涛动指数 (SOI) 之间的显着线性联系分别在夏季和春季被确认。