DOI: 10.25921/0y81-tt67
title: NOAA/WDS Paleoclimatology - Southern-Central England 1000 Year March-July Precipitation Reconstruction

description: We present a millennial long dendroclimatic reconstruction of spring/summer precipitation for southern-central England. Previous research identified a significant moisture stress signal in ring-width data measured from oak trees growing in southern England. In this study, we build upon this earlier work, specifically targeting south-central England, to derive a well replicated oak ring-width composite chronology using both living and historical material.  The data-set includes 352 living trees (AD 1629-2009) and 1540 individual historical series (AD 663-1925). The period expressed by at least 50 trees in any year is AD 980-2009.  Calibration experiments identify the optimal seasonal predictand target as March-July precipitation (1901-2007: r2 = 0.33). However, comparison with the long Kew Gardens precipitation record indicates a weakening in tree-growth/climate response from ~1800 to 1920 which we speculate may be related to smoke and sulphur dioxide (SO2) emissions at that time which may have also contributed to a decrease in tree productivity. The time-series derived using the regional curve standardisation method to capture lower frequency information shows a mediaeval period with alternating multi-decade-long dry and wet periods, with AD 1153-1172 being the wettest reconstructed 20-year period in the whole record. Drier conditions are prevalent from ~1300 to the early sixteenth century followed by a period of increasing precipitation levels. The most recent four centuries of the record appear similar to the mediaeval period with multiple decade-long dry and wet periods. The late twentieth century is the second reconstructed wettest period. These centennial hydroclimatic trends are in broad agreement with independent regional scale hydroclimatic reconstructions from tree-ring (East Anglia), historical, speleothem and peat water level proxy archives in the United Kingdom and appear coupled with reconstructed sea surface temperature changes in the North Atlantic which in turn influence the Atlantic meridional overturning circulation and westerly airflow across the UK.
description: May-July precipitation reconstruction for southern-central England 
covering the last millennium, based on Oak ring width chronologies. 
Two chronology versions were developed for the full south-central 
England composite oak data-set.  To maximise high-mid frequency 
common variability, the ringwidth data were initially detrended 
using 100-year splines (SPL100).  Ring-width data were reprocessed 
using the regional curve standardisation (RCS) method, which can 
potentially capture secular-scale variability at frequencies 
greater than the mean length of the samples. The RCS chronology 
is referred to as RCSsf, and is utilized for the May-July 
precipitation reconstruction. 


Summary information for the individual living ring-width chronologies

Site name            Code        SOURCE    County         Region   #Series   FullLength     Lat.°N  Long.°E   Elev.(m)   RBAR      EPS     N(EPS 0.85)
Ludlow               BRIT010     ITRDB     Shropshire     CENT        15      1823-1978      52.21    -2.44      185    0.485     0.93        6
Stoneleigh Abbey     STO         Oxford    Warwickshire   CENT        16      1701-1998       52.2    -1.32       70    0.241     0.84     17.8
Bradfield            BRIT031     ITRDB     Warwickshire   CENT        10      1879-1984      52.15    -1.15      130     0.42     0.88      7.8
Charlbury            BRIT059     ITRDB     Oxfordshire    SE          17      1828-1979      51.52     -1.3      130    0.473     0.94      6.3
Yanworth             BRIT060     ITRDB     Gloucestshire  SE          24      1738-1979      51.49    -1.54      180    0.427     0.95      7.6
Oakley               BRIT4       ITRDB     Oxfordshire    SE          16      1847-1978      51.48    -1.07       70    0.455     0.93      6.8
Wytham Woods         WYT         Oxford    Oxfordshire    SE          22      1766-1999      51.46     -1.2      130    0.396     0.94      8.7
Brasenose Wood       BSN         Oxford    Oxfordshire    SE          41      1757-2009      51.44    -1.11      100    0.348     0.96     10.6
Radley               BRIT061     ITRDB     Oxfordshire    SE          18      1812-1979      51.42    -1.13       70    0.531     0.95        5
Hardwick Estate      HWK         Oxford    Oxfordshire    SE          21      1764-1999       51.3    -1.02      140    0.301      0.9     13.2
Mapledurham Estate   MPL         Oxford    Oxfordshire    SE          73      1751-2009      51.29    -1.01      100    0.252     0.96     16.8
Savernake            BRIT063     ITRDB     Wiltshire      SW          23      1725-2006      51.24    -1.42      170    0.301     0.91     13.2
Salisbury            BRIT062     ITRDB     Wiltshire      SW          10      1797-1968      51.24    -1.42      170    0.457     0.89      6.7
Bath                 BRIT2       ITRDB     Somerset       SW          14      1754-1979      51.22    -2.19       45    0.373     0.89      9.5
Crabwood             BRIT064     ITRDB     Hampshire      SE          31      1629-2009      51.04    -1.23      120    0.315     0.93     12.3

RBAR = mean inter-series correlation 
EPS = expressed population signal 
N (EPS 0.85) is the theoretical number of trees needed to acquire an EPS value of 0.85
ITRDB - International Tree Ring Data Bank, http://www.ncdc.noaa.gov/paleo/treering.html 
Oxford - Oxford University tree-ring laboratory. Not publicly archived at this time