A statistical approach to construct composite climate records of dated archives
A statistical approach to construct composite climate records of dated archives
复制标题
DOI：
10.1016/j.quageo.2012.06.007
复制
发表时间：
2012-12-01
影响因子：
2.7
通讯作者：
Fohlmeister, J.
中科院分区：
文献类型：
--
作者：
Fohlmeister, J.
石笋等年代久远的环境档案的代用记录可用于重建过去的气候，因此对古气候研究具有重要意义。然而，测年条件往往并不完美，以获得精确的年龄与小的不确定性。在这个问题上，使用的统计方法适用于复制气候信号的几个附近位于标本，如石笋从一个洞穴，可以帮助减少年龄的不确定性。在MATLAB中实现的一种新方法使用蒙特卡罗方法确定绝对年龄，以找到几个信号再现相邻档案的气候代理之间的最佳相关性。因此，该程序能够将联合收割机气候代用指标组合起来，构成一个复合记录。这种“站点内相关年龄建模”（iscam）方法提供了巨大的优势。在重叠的时间间隔内，年龄不确定性可以显著降低，并且可以测试感兴趣的信号在两个记录中是否确实相似。此外，iscam允许扩大单个记录的时间跨度，而同时在存在重复的时期内提高组合记录的信噪比。相关性的显著性水平可以从一阶自回归过程（AR 1）针对红噪声背景来计算，这允许确定足够的年龄不确定性。该方法旨在同步附近位置的时间序列，其中气候信号的变化同时发生。由于气候系统中未知的超前和滞后，将这种方法应用于地理上分散的地点可能不合适。(c)2012爱思唯尔有限公司版权所有。
Proxy records of dated environmental archives like stalagmites are used for reconstruction of past climate and therefore are of fundamental interest for the paleoclimate community. However, dating conditions are often not perfect to obtain precise ages with small uncertainties. On this matter, the use of statistical approaches applied to reproduced climate signals of several nearby situated specimens, like stalagmites from one cave, can help to reduce age uncertainties. A new method implemented in MATLAB uses a Monte Carlo approach on absolute age determinations to find the best correlation between climate proxies of several signal reproducing adjacent archives. Therefore, the program is able to combine climatic proxies to construct a composite record. This "intra-site correlation age modelling" (iscam) approach offers great advantages. The age uncertainty can be significantly reduced within the overlapping time intervals and it can be tested if the signal of interest is indeed similar in both records. Additionally, iscam allows to enlarge the time span of a single record while at the same time the signal to noise ratio of the combined record improves in periods where replicates exist. Significance levels of the correlation can be calculated against the red-noise background from a first order autoregressive process (AR1), which allows to determine adequate age uncertainties. The method was designed to synchronize time series of nearby locations, where changes in the climate signal occur simultaneously. Applying this method to geographically dispersed locations might not be appropriate due to unknown leads and lags in the climate system. (c) 2012 Elsevier B.V. All rights reserved.