Abstract Arctic precipitation is predicted to increase in the coming century, due to a combination of enhanced northward atmospheric moisture transport and local surface evaporation from ice-free seas. However, large model uncertainties, limited long-term observations, and high spatiotemporal variability limit our understanding of these mechanisms, emphasizing the need for paleoclimate records of precipitation changes. Here we use lipid biomarkers in lake sediments to reconstruct precipitation seasonality in northern Spitsbergen, Svalbard. We measured the hydrogen isotopic ratios (δ2H) of n-alkanoic acids (C20–C30) from sedimentary leaf waxes in lake Austre Nevlingen, Spitsbergen. We interpret δ2H values of mid-chain (C22) and long-chain (C28) n-alkanoic acids to represent δ2H of lake and soil water, respectively. Austre Nevlingen lake water δ2H reflects amount-weighted mean annual precipitation δ2H. In contrast, soil water is mostly recharged by summer rainfall, and therefore reflects δ2H values of summer precipitation. Austre Nevlingen leaf wax δ2H values are 2H-depleted in the Early Holocene, suggesting high winter precipitation amounts. This coincides with high summer insolation, strong Atlantic water advection and reduced spring sea-ice cover in surrounding waters. Winter precipitation continued to dominate until c. 6 cal. kyr BP. After 6 cal. kyr BP, the trend in the biomarker record is not as clear. This could be related to colder conditions causing longer duration of seasonal lake-ice cover, thereby influencing the precipitation seasonality registered by the lake water. The Austre Nevlingen record suggests a close relationship between precipitation seasonality and regional ocean surface conditions, consistent with simulations suggesting that Arctic winter sea-ice loss will lead to increased local evaporation.

中文翻译：

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斯瓦尔巴群岛北部全新世降水季节性：海冰和区域海洋表面条件的影响

摘要 由于向北大气水分输送增强和无冰海的局部表面蒸发相结合，预计未来一个世纪北极降水将增加。然而，大的模式不确定性、有限的长期观测和高时空变异性限制了我们对这些机制的理解，强调需要对降水变化进行古气候记录。在这里，我们使用湖泊沉积物中的脂质生物标志物来重建斯瓦尔巴群岛斯匹次卑尔根岛北部的降水季节性。我们测量了斯匹次卑尔根 Austre Nevlingen 湖沉积叶蜡中正链烷酸 (C20–C30) 的氢同位素比 (δ2H)。我们解释中链 (C22) 和长链 (C28) 正链烷酸的 δ2H 值分别代表湖泊和土壤水的 δ2H。Austre Nevlingen 湖水 δ2H 反映了加权平均年降水量 δ2H。相比之下，土壤水主要由夏季降雨补给，因此反映了夏季降水的δ2H值。Austre Nevlingen 叶蜡 δ2H 值在全新世早期耗尽 2H，表明冬季降水量较高。这与夏季高日照、强烈的大西洋水平流和周围水域春季海冰覆盖减少相吻合。冬季降水继续占主导地位，直到 c。6 卡路里 基尔 BP。6 卡路里后。kyr BP，生物标志物记录中的趋势并不那么清楚。这可能与较冷的条件导致季节性湖冰覆盖持续时间更长，从而影响湖水记录的降水季节性有关。