Producing an enhanced millennium-length temperature reconstruction from tree-ring density for the European Alps

我将开发一个新的和改进的千年长度的树轮最大晚材（MXD）为欧洲阿尔卑斯山的温度重建。熟练的，每年解决代理记录，跨越整个过去的千年，迫切需要把最近的变暖到一个历史背景下，并与不同的强制中世纪温暖期（MWP）进行比较。Büntgen等人（2006年）制作了欧洲阿尔卑斯山的MXD年表，导致了高度引用和有影响力的千年温度重建。然而，这种重建有关键的局限性，将在本项目中加以解决和消除：（i）欧洲阿尔卑斯山的活树没有达到千年的年龄，因此Büntgen等人（2006年）使用历史建筑的木材来延长年表。然而，木材材料的确切来源是未知的，来自林木线和非林木线地点的树木之间的气候信号可能有所不同。我将执行一个活树多站点采样沿着海拔断面和应用一个活树为基础的种源模型的历史材料，估计其起源，并获得强大的气候信号。(ii)Büntgen等人（2006年）记录的底层样本来自瑞士不同的亚高山山谷，所有1200年前的样本都来自Simplon地区的建筑物，而最近的数据来自Lötschental的建筑物和活树。这些山谷之间的生态差异尚未评估，但很可能影响年表和派生的温度重建，这是反映在记录的统计差异。在这个项目中，我将根据Simplon山谷的生态同质数据制作MXD年表，以匹配覆盖整个MWP的现有数据。(iii)Büntgen等人（2006年）年表中的样本复制在公元1200年左右很低，强调了个体树的反应，削弱了年表信号的强度。我已经获得了涵盖这一关键时期的其他样本，并将开发一个复制良好且时间上可靠的MXD年表，可以追溯到中世纪。(iv)由于Büntgen等人的重建工作于2004年结束，因此无法将最近最温暖的几十年置于长期背景下。我将制作一个更新的千年温度重建，延长到2018年，并提供可靠的估计回到中世纪。我与Büntgen et al.（2006）论文的原作者保持密切联系，并将有权访问进行该项目所需的所有数据和Meta信息，以及MXD设备（DFG Großgeräte资助），该设备以与原始数据完全相同的方式进行测量，允许直接整合所有数据。新的千年尺度温度重建和基础数据将在出版后在适当的平台（NOAA和ITRDB）上提供。

I will develop a new and improved millennium-length tree-ring maximum latewood (MXD) based temperature reconstruction for the European Alps. Skillful, annually resolved proxy records, spanning the entire past millennium, are urgently needed to place recent warming into a historical context and compare with the differently forced Medieval Warm Period (MWP). Büntgen et al. (2006) produced a MXD chronology for the European Alps, resulting in a highly cited and influential millennium-length temperature reconstruction. However, this reconstruction has crucial limitations which will be addressed and eliminate within this project: (i) Living trees do not reach millennial age in the European Alps, thus timbers from historical buildings were used by Büntgen et al. (2006) to extend the chronology back into time. The exact provenance of the timber material is, however, unknown and climate signals may vary between trees from treeline and non-treeline sites. I will perform a living tree multiple-site sampling along elevational transects and apply a living tree-based provenance model to the historical material for estimating its origin and to gain robust climate signals. (ii) The underlying samples in the Büntgen et al. (2006) record originate from different subalpine valleys in Switzerland, with all pre-1200 samples exclusively originating from buildings in the Simplon region, while the recent data is from buildings and living trees in the Lötschental. The ecological differences among these valleys have not been assessed, but very likely influence the chronology and derived temperature reconstruction, which is reflected by statistical discrepancies in the record. Within this project, I will produce a MXD chronology based on ecological homogenous data from the Simplon valley to match the existing data covering the entire MWP. (iii) Sample replication in the Büntgen et al. (2006) chronology is low around 1200 AD emphasizing individual tree responses and weakening the chronology signal strength. I already have access to additional samples covering this crucial period and will develop a well replicated and temporally robust MXD chronology back to Medieval times. (iv) As the Büntgen et al. reconstruction ends in 2004, it cannot be used to place the recent warmest decades into a long-term context. I will produce an updated millennium-length temperature reconstruction extended until 2018 and providing robust estimates back to Medieval times. I am in close contact to the original authors of the Büntgen et al. (2006) paper and will have access to all data and meta information needed to conduct this project and to a MXD device (DFG Großgeräte funding) that measures in the exact same way as the original data, allowing a direct integration of all data. The new millennial scale temperature reconstruction and the underlying data will be made available on appropriate platforms (NOAA and ITRDB) upon publication.