Authors: Giles H F Young Neil J Loader Danny McCarroll Roderick J Bale Joanne C Demmler Daniel Miles Nigel T Nayling Katja T Rinne Iain Robertson Camilla Watts Matthew Whitney
Publish Date: 2015/03/25
Volume: 45, Issue: 11-12, Pages: 3609-3622
Abstract
United Kingdom UK summers dominated by anticyclonic circulation patterns are characterised by clear skies warm temperatures low precipitation totals low air humidity and more enriched oxygen isotope ratios δ18O in precipitation Such conditions usually result in relatively more positive enriched oxygen isotope ratios in tree leaf sugars and ultimately in the treering cellulose formed in that year the converse being true in cooler wet summers dominated by westerly air flow and cyclonic conditions There should therefore be a strong link between treering δ18O and the amount of summer precipitation Stable oxygen isotope ratios from the latewood cellulose of 40 oak trees sampled at eight locations across Great Britain produce a mean δ18O chronology that correlates strongly and significantly with summer indices of total shear vorticity surface air pressure and the amount of summer precipitation across the England and Wales region of the United Kingdom The isotopebased rainfall signal is stronger and much more stable over time than reconstructions based upon oak ring widths Using recently developed methods that are precise efficient and highly costeffective it is possible to measure both carbon δ13C and oxygen δ18O isotope ratios simultaneously from the same treering cellulose In our study region these two measurements from multiple trees can be used to reconstruct summer temperature δ13C and summer precipitation δ18O with sufficient independence to allow the evolution of these climate parameters to be reconstructed with high levels of confidence The existence of long wellreplicated oak treering chronologies across the British Isles mean that it should now be possible to reconstruct both summer temperature and precipitation over many centuries and potentially millenniaWe acknowledge support from C3W GHFY NJL DMc the Scottish Pine Project NJL early stage research funding from the University of Wales Trinity Saint David RJB and The Leverhulme Trust Grant No RPG2014327 GHFY NJL DMc DM We thank CCW now NRW for SSSI consent and the National Trust for assisting with access at Dinefwr and Allt Lanlas RJB NTN
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