SCOT2K: Reconstructing 2000 years of Scottish climate from tree-rings

SCOT2K项目旨在利用树木年轮数据重建苏格兰高地过去2000年的夏季温度。英国北部的这种气候重建，以及斯堪的纳维亚半岛正在开发的类似的树木年轮数据集，不仅将提供关于中世纪气候、向小冰河时代(约公元1300年)的过渡以及当前区域气候变化的重要信息，而且还将有助于确定北大西洋对欧洲西北部地区气候的影响。通过了解这些生物如何对这些因素做出反应，就有可能使用树木年轮测量来不仅重建过去的气候，而且评估管理实践可能如何影响过去的树木生长。在苏格兰高地，苏格兰松树的树龄很少超过200-300年。因此，要研究约1700年前的过去环境变化，需要使用保存下来的当地木质材料将活松树年代学延长到过去。可能有两种材料来源：来自建筑物的历史木材和保存在泥炭/湖泊沉积物中的亚化石材料。这个项目将利用这两种保存下来的松树材料，将活着的年表延长到过去。一般来说，同一物种的树木对相对较大区域的环境条件做出类似的反应。因此，同一地区同一树种的所有树木之间存在一定程度的共同生长变异性。这种常见的变异性导致了宽环和窄环的共享模式(即，就像条形码)，可以在样本之间匹配，从而允许在样本测年之间进行匹配。这种同步或模式匹配过程被称为“交叉约会”。通过交叉测年，历史或亚化石木质材料可以确定日历日期，只要与已经确定日期的参考年代学有合理的重叠(~80年)即可。初步结果表明，在拟议的SCOT2K项目的时间框架内，2000年的年表是一个可行和现实的目标，而8000年的长期年表在理论上是可能的，尽管这是一个更具挑战性的长期目标。该项目建议从苏格兰高地的历史建筑和湖泊中采集保存下来的松树材料，交叉样本，得出该地区2000年的气候敏感树轮年表。除了环宽度(RW)数据外，还将从样本中测量最大密度(MXD)和最小蓝色强度(BI)数据。MXD和BI都是衡量年轮晚材中木质素含量的指标，其含量受到夏季温度的强烈控制。利用RW、MXD和BI，可以为苏格兰高地开发一个稳健的、经过强烈校准的夏季温度重建。从SCOT2K项目获得的数据不仅将提供过去两千年来英国北部过去气温的重要信息，还将提供控制不列颠群岛十年和更长期气候变化的北大西洋可变性的关键信息。通过与在斯堪的纳维亚半岛进行类似研究的研究小组(其他树轮科学家和气候模型师)的互动，这项工作的重要性将大大增强。提议为该项目第三年举办一次合成讲习班，以促进这一重要的合作。

The SCOT2K project aims to reconstruct summer temperatures in the Scottish Highlands for the last 2000 years using tree-ring data. Such a climate reconstruction for Northern Britain, along with similar tree-ring data-sets being developed in Scandinavia, will not only provide important information on medieval climate, the transition into the Little Ice Age (~1300 AD) and current regional climate change, but will also help ascertain the influence of the North Atlantic on the climate of the NW European region.Trees respond to a variety of environmental factors. By understanding how these organisms respond to such factors, it is possible to use tree-ring measurements to not only reconstruct past climate but also assess how management practises may have influenced tree-growth in the past. In the Scottish Highlands, Scots pine trees rarely attain ages greater than ~200-300 years. Therefore, to study past environmental change prior to ~1700, living pine chronologies need to be extended back in time using preserved local woody material. There are potentially two sources of material; historic timbers from buildings and sub-fossil material preserved in peat/lake sediments. This project will utilise both sources of preserved pine material to extend the living chronologies back in time.In general, trees of the same species respond in a similar way to environmental conditions over relatively large areas. There is therefore a certain degree of common growth variability between all trees of the same species from the same region. This common variability results in a shared pattern of wide and narrow rings (i.e. like a bar code) that can be matched between samples allowing between sample dating. This synchronising or pattern matching process is termed "crossdating". Through crossdating, historical or sub-fossil woody material can be calendar dated, so long as there is reasonable overlap (~80 years) with an already dated reference chronology. Initial results indicate that a 2000 year chronology is a feasible and realistic objective within the timeframe of the proposed SCOT2K project and that an ~8000 year long chronology, an albeit more challenging long term aim, is theoretically possible in the future.This project proposes to sample preserved pine material from both historic structures and lakes in the Scottish Highlands, crossdate the samples and derive a 2000-year long climatically sensitive tree-ring chronology for the region. As well as ring-width (RW) data, maximum density (MXD) and minimum blue intensity (BI) data will also be measured from the samples. MXD and BI are both measures of lignin content in the latewood of a tree-ring, the amount of which is strongly controlled by summer temperatures. Using RW, MXD and BI, a robust, strongly calibrated summer temperature reconstruction can be developed for the Scottish Highlands. The data obtained from the SCOT2K project will not only provide important information of past temperatures over the last two millennia for northern Britain, but will also provide key information on North Atlantic variability which controls decadal and longer term climate variability over the British Isles. The importance of this work will be greatly enhanced by interaction with research groups (other tree-ring scientists and climate modellers) undertaking similar research across Scandinavia. A synthesis workshop is proposed for Year 3 of the project to facilitate this important collaboration.