Reconstructing North Atlantic marine climate variability using an absolutely-dated sclerochronological network

D.J Reynolds,C.A Richardson,J.D Scourse,P.G Butler,P Hollyman,A Román-González,I.R Hall

doi:10.1016/j.palaeo.2016.08.006

D.J Reynolds, C.A Richardson + Show 5 more

Open Access

https://doi.org/10.1016/j.palaeo.2016.08.006

Copy DOI

Abstract

Reconstructing regional to hemispheric-scale climate variability requires the application of spatially representative and climatically sensitive proxy archives. Large spatial networks of dendrochronologies have facilitated the reconstruction of atmospheric variability and inferred variability in the Atlantic Ocean system. However, the marine environment has hitherto lacked the direct application of the spatial network approach because of the small number of individual absolutely-dated marine archives. In this study we present the first analyses of a network of absolutely-dated annually-resolved growth increment width chronologies from the marine bivalves Glycymeris glycymeris and Arctica islandica. The network contains eight chronologies spanning >500km along the western British continental shelf from the southern Irish Sea to North West Scotland. Correlation analysis of the individual chronologies and a suite of climate indices, including the Atlantic Multidecadal Oscillation (AMO), Central England surface air temperature (CET), northeast Atlantic sea surface temperatures (SST's) and the winter North Atlantic Oscillation (wNAO), demonstrates that, despite the large geographical distances been sites and the heterogeneous nature of the marine environment, the increment width variability in these series contains an element of coherence likely driven by a common response to changing environmental forcing. A nested Principal component analysis (PCA) was used to construct five composite series which explain between 31% and 74% of the variance across the individual chronologies. Linear regression analyses indicate that the composite series explain up to 41% of the variance in Northeast Atlantic SSTs over the calibration period (1975–2000). Calibration verification (reduction of error [RE] and coefficient of efficiency [CE]) statistics indicate that the composite series contains significant skill at reconstructing multi-decadal northeast Atlantic SST variability over the past two centuries (1805–2010). These data suggest that composite series derived from sclerochronology networks can facilitate the robust reconstruction of marine climate over past centuries to millennia providing invaluable baseline records of natural oceanographic variability.

Highlights

Developing a detailed understanding of the role the North Atlantic Ocean plays in the wider climate system is essential for developing precise predictions of future climate variability
The presence of a regional signal in the composite series we examine supports evidence derived from the analyses of multiple geoduck chronologies (Black et al, 2009), otolith chronologies (Matta et al, 2016; Black et al, 2011) and cross-species otolith, molluscan and tree growth increment analyses (Black, 2009; Black et al, 2008) that sclerochronological networks contain coherent growth signals even if the individual chronologies they contain are separated by large distances
The results presented here suggest that composite series derived from sclerochronological networks potentially contain comparable levels of skill with the best performing reconstructs of mean annual Atlantic Multidecadal Oscillation (AMO), SSTs, Central England surface air temperature (CET) and the winter North Atlantic Oscillation (wNAO) derived from individual chronologies (Table 6)

Summary

Introduction

Developing a detailed understanding of the role the North Atlantic Ocean plays in the wider climate system is essential for developing precise predictions of future climate variability. The integration of chronologies covering such a wide geographic range allows purely local variability to be averaged out, resulting in a stronger broad scale (regional to hemispheric) climate signal to be deconvolved (Wilson et al, 2010). Such networks have hitherto facilitated the reconstruction of hemispheric surface air temperatures A few recent studies (Cunningham et al, 2013; McGregor et al, 2015) have made use of networks of marine sedimentary archives, dated by means of radiocarbon derived age models. The recent increase in the development of absolutely-dated climatically sensitive sclerochronological records (e.g. Brocas et al, 2013; Butler et al, 2013; Reynolds et al, 2013), derived from the annually resolved growth increments contained in long-lived marine bivalve molluscs, presents the first opportunity for the development of annually resolved marine spatial networks directly analogous to the dendrochronological networks

Methods

Results

Discussion

Conclusion