Influences of high reliefs on isotope hydrology and coupled climate proxies

气候代用指标，如树木年轮，依赖于稳定的同位素比值来重建古气候条件。然后，利用这些信息可以校准评估和预测全球气候变化目前和未来影响的模型。根据模型预测，西地中海是一个将面临严重气候变化的地区。因此，该地区的科西嘉岛一直是利用树木年代学和稳定同位素重建古气候的目标。然而，氧稳定同位素结果从科西嘉松还不能得到令人满意的解释。树木年轮氧稳定同位素δ 18O值主要取决于当地降水和土壤水的氧同位素比值。降水δ 18O值随温度、海拔高度和水汽源区的不同而变化。这些参数现在确定得相当精确，但在过去需要假设。一个重要的同位素效应是所谓的海拔效应，它描述了降水的δ 18 O值与海拔的关系。国际原子能机构（原子能机构）的大型全球降水同位素网络数据库可以对同位素效应进行良好的区域估计。然而，在地势高陡的地区，事情变得更加困难。一些最新的出版物表明，在特定的季节，这些地区不存在海拔梯度。观测的原因可能是大气行星边界层（PBL）的季节性高度变化。该同位素水文学提案是CorsicArchive项目包的一部分，该项目包还包括气候，树木同位素和树木生态学的相互关联提案。计划安装9个同位素降水取样器，并沿沿着东西向垂直样带定期取样。这项建议将具体探讨边界层的动力学和同位素高度效应。其他问题涉及气团的水分来源和岛屿水文循环中的局部水分循环。此外，土壤水和地表水的分析计划跟踪和量化的delta18 O值的变化沿着水的路径的树木年轮。该提案的方法旨在填补目前高起伏同位素水文学知识的空白，并最终导致对气候变化敏感区域的相关气候代用指标进行更可靠的解释。关于目前的气候变化，必须了解过去的气候变化及其触发因素，以便更好地预测未来的变化。

Climate proxies such as tree rings rely on stable isotope ratios for the reconstruction of palaeoclimatic conditions. Such information then allow the calibration of models that evaluate and predict ongoing and future effects of global climate change. According to model predictions, the western Mediterranean is a region that will face severe climatic changes. Therefore, the island of Corsica in that region has been the target for palaeoclimate reconstructions by means of dendrochronology and stable isotopes. However, the oxygen stable isotope results from Corsican pines could not yet be interpreted satisfactorily. The oxygen stable isotope values (delta18O) of tree rings mainly depend on the oxygen isotope ratio of local precipitation and soil water. The precipitation delta18O values vary according to temperature, altitude and the moisture source area. Such parameters are determined nowadays rather precise but need to be assumed for the past. An important isotope effect is the so-called altitude effect that describes the relation of the delta18O value of precipitation and altitude. The large global network of isotopes in precipitation (GNIP) database of the International Atomic Energy Agency (IAEA) allows for a good regional estimate of isotope effects. However, things become more difficult in regions with high and steep mountain reliefs. Some latest publications suggest that the altitude gradient is absent in such regions during specific seasons. The reason for that observation could be seasonal height variations of the atmospheric planetary boundary layer (PBL). This isotope hydrology proposal is part of the project package CorsicArchive that also consists of interlinking proposals for climate, dendroisotopes and dendroecology. It is planned to install and regularly sample nine isotope precipitation samplers along an east-west altitudinal transect. This proposal will specifically explore the dynamics of the PBL and the isotope altitude effect. Additional questions relate to moisture source of air masses and the local moisture recycling within the islands hydrologic cycle. Furthermore, soil water and surface water analyses are planned to trace and quantify changes of the delta18O values along the pathway of water to the tree rings. The approach of this proposal aims to fill the gaps in the current knowledge of isotope hydrology of high reliefs and will finally lead to a more robust interpretation of related climate proxies in a climate change sensitive region. With respect to the current climate change, it is essential to understand climatic variations and its triggers in the past to better predict future changes.