Stable isotopes of oxygen (δ 18 O) and hydrogen (δ 2 H) in precipitation are widely employed tracers of the global hydrologic cycle, and are frequently inferred from lake-water-derived proxies in sediments of high-latitude lakes. Lake-water isotope proxies archive precipitation δ 18 O and δ 2 H values, modulated by lake hydrological processes, which may be functionally classified into processes that affect source water isotope values (i.e. inflow δ 18 O and δ 2 H) and catchment-integrated evaporation. Respectively, these controls form the basis of interpretations of precipitation isotope and effective precipitation signals from lake-water isotope proxy records. Conventionally, a single control on lake water isotope variability is assumed for a given record. Yet sensitivity to these controls depends on regional hydroclimate and local hydrology, which may change through time. We quantified the relative impacts of variations in inflow δ 18 O and evaporative 18 O enrichment on lake water δ 18 O in response to spatially variable aridity, using measurements of lake water δ 2 H and δ 18 O from 140 western Greenland lakes located between the Labrador Sea and western Greenland Ice Sheet margin. We calculated source water δ 18 O of lake waters (δI) using a recently developed Bayesian method and quantified evaporation-to-inflow ratios (E/I) using a modified Craig-Gordon model. δI varied by 11.1‰ across the study region, superimposed by evaporative 18 O enrichment of up to 20.0‰ and E/I ranging from nearly no evaporative loss (E/I < 0.10) to desiccation (E/I > 1). Lakes can be broadly classified as predominantly sensitive to inflow or evaporation, corresponding to their location along the aridity gradient, and there are significant trends in both δI and E/I across the study area. Substantial local variability in δI and E/I suggests catchment hydrology determines the sensitivity of δI and E/I to changes in aridity, and implies that hydrological end-member lakes within a small region may provide complementary records of seasonal precipitation isotope values and ice-free-season evaporation. Deconvolving modern controls on lake water isotope values provides essential support for quantitative and seasonal paleoclimate inferences from paleolimnological isotope data, which will improve constraints on the long-term variability of the Arctic hydrologic cycle.

中文翻译：

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解决流入和蒸发对格陵兰西部湖水同位素的综合影响，为古气候推断提供信息

降水中氧 (δ 18 O) 和氢 (δ 2 H) 的稳定同位素是广泛使用的全球水文循环示踪剂，并且经常从高纬度湖泊沉积物中的湖水衍生代用品中推断出来。湖水同位素代表档案降水 δ 18 O 和 δ 2 H 值，受湖泊水文过程调制，在功能上可分为影响源水同位素值的过程（即流入 δ 18 O 和 δ 2 H）和集水区整合蒸发。这些控制分别构成了解释降水同位素和来自湖水同位素替代记录的有效降水信号的基础。通常，对于给定的记录，假设对湖水同位素变异性进行单一控制。然而，对这些控制的敏感性取决于区域水文气候和当地水文，这可能会随着时间而改变。我们量化了流入 δ 18 O 和蒸发 18 O 富集变化对湖水 δ 18 O 的相对影响，以响应空间可变干旱，使用来自位于格陵兰岛之间的 140 个西部格陵兰湖泊的湖水 δ 2 H 和 δ 18 O 的测量值。拉布拉多海和格陵兰岛西部冰盖边缘。我们使用最近开发的贝叶斯方法计算了湖水的源水 δ 18 O (δI)，并使用改进的 Craig-Gordon 模型量化了蒸发流入比 (E/I)。整个研究区域的 δI 变化为 11.1‰，叠加了高达 20.0‰ 的蒸发 18 O 富集和 E/I，范围从几乎没有蒸发损失 (E/I < 0.10) 到干燥 (E/I > 1)。湖泊可以大致分为对流入或蒸发主要敏感，对应于它们沿干旱梯度的位置，并且整个研究区域的 δI 和 E/I 都存在显着趋势。δI 和 E/I 的大量局部变异表明流域水文决定了 δI 和 E/I 对干旱变化的敏感性，并暗示小区域内的水文端元湖泊可以提供季节性降水同位素值和冰-自由季节蒸发。对湖水同位素值的现代控制进行解卷积为从古湖泊学同位素数据进行定量和季节性古气候推断提供了必要的支持，这将改善对北极水文循环长期变异性的限制。δI 和 E/I 的大量局部变异表明流域水文决定了 δI 和 E/I 对干旱变化的敏感性，并暗示小区域内的水文端元湖泊可以提供季节性降水同位素值和冰-自由季节蒸发。对湖水同位素值的现代控制进行解卷积为从古湖泊学同位素数据进行定量和季节性古气候推断提供了必要的支持，这将改善对北极水文循环长期变异的限制。δI 和 E/I 的大量局部变异表明流域水文决定了 δI 和 E/I 对干旱变化的敏感性，并暗示小区域内的水文端元湖泊可以提供季节性降水同位素值和冰-自由季节蒸发。对湖水同位素值的现代控制进行解卷积为从古湖泊学同位素数据进行定量和季节性古气候推断提供了必要的支持，这将改善对北极水文循环长期变异性的限制。