0897669409 - From Keith Briffa To...

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From: Keith Briffa <[email protected]> To: [email protected] Subject: Re: report- edit this and send an email Date: Fri Jun 12 12:36:49 1998 >Return-path: <[email protected]> >Envelope-to: [email protected] >Delivery-date: Tue, 12 May 1998 17:42:11 +0100 >X-Sender: [email protected] >Date: Tue, 12 May 1998 16:42:31 +0000 >To: Keith Briffa <[email protected]> >From: Mike Baillie <[email protected]> >Subject: Re: report- edit this and send an email > >Keith, here are some thoughts on belfast work. Come back to me on this. >Cheers Mike > >10K Belfast Report. > >All the remaining long chronology (prehistoric) oak data from Ireland, >England, north and south Germany (including the major Hohenhein holdings >(2827 tree series spanning 8239 BC to 841 AD) and the Netherlands (667 >series spanning 6025 BC with gaps to 1721 AD) has now been centralised and >screened. >Work has been progressing on calculating running statistics on and between >these data sets and their constituent ring patterns. Additional attention >has been paid to attempting to understand/interpret the data in various >ways. During the year, three principal work packages have been explored >with respect to assessing the oak data. > >work package i) >signatures >With such a wide grid of chronologies it is possible to review the >occurrence of years of common growth trend. Signatures are normally >defined as those years in which 80% or more of all trees in a 'region' >exhibit the same trend towards wider or narrower growth. All sub-regional >and overall European signatures have been isolated and the intention is to >re-do the 1985 analysis of Kelly et al. comparing rainfall, temperature and >drought index data with the ocurrence of widespread signatures. > >work package ii) >Stepped windows of correlation >With the availability of the raw data from each laboratory all regional >chronologies for Ireland, Britain, North Germany and South Germany have >been reconstructed by standard means (initially fitting a 30-year spline to >each individual tree-ring pattern). Using these standardised chronologies, >stepped windows of correlation have been run comparing all regions across >time back to 5000 BC. Notable changes are observed indicating periods of >consistent, north-European-wide similarity and dis-similarity. The >availability of the raw data then allows interrogation of anomalies. For >example, there is a notable fall-off in correlation between the >standardised Irish and English chronologies at AD 775 to 825. In the past
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0897669409 - From Keith Briffa To...

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