date: Tue Mar 4 14:47:10 2008 from: Keith Briffa subject: Re: JQS-08-0020 - reviewing to: pcoxon@tcd.ie Dear Pete I will review this - hopefully within your deadline. Please forward the pdf best wishes KeithAt 10:25 04/03/2008, you wrote: Dear Professor Briffa Manuscript # JQS-08-0020 entitled "Summer temperature variations in Lapland during the Medieval Warm Period and the Little Ice Age relative to natural instability of thermohaline circulation" has been submitted to the Journal of Quaternary Science. As an acknowledged expert in this field I am inviting you to review this manuscript. The abstract appears at the end of this letter, along with the names of the authors. Please let me know within 5 days if you will be able to review this paper and if you can I will attach a PDF file of the manuscript. I would ask that you complete your review within 3 weeks and no longer than 4 weeks from receipt. If you are unable to review this paper, would you take a moment to please recommend one or two other possible referees with expertise in this area. Sincerely, Prof. Pete Coxon Journal of Quaternary Science MANUSCRIPT DETAILS TITLE: Summer temperature variations in Lapland during the Medieval Warm Period and the Little Ice Age relative to natural instability of thermohaline circulation AUTHORS: Helama, Samuli; Timonen, Mauri; Holopainen, Jari; Ogurtsov, Maxim; Mielikäinen, Kari; Eronen, Matti; Lindholm, Markus; Meriläinen, Jouko ABSTRACT: New tree-ring based analysis for climate variability at regional scale is presented for high altitudes of Europe. Our absolutely dated temperature reconstruction seeks to characterize the summer temperatures since AD 750. The warmest and coolest reconstructed 250-year periods occurred AD 931-1180 and AD 1601-1850, respectively. These periods owe significant temporal overlap with the general hemispheric climate variability due to the Medieval Warm Period (MWP) and the Little Ice Age (LIA). Further, we detect an approx. 50-60-year rhythm, attributable to instability of the North Atlantic deep water, in the regional climate during the MWP but not during the LIA. Intensified formation of the North Atlantic deep water further appeared coincident to the initiation and continuation of MWP, the mid-LIA transient warmth occurring during the period AD 1391-1440, and to recent warming. Our results suggest that the internal climate variability (i.e. thermohaline circulation) could have played a role behind the earlier start of the MWP in several proxy reconstructions compared to the externally forced model simulations. ========================== Sign up for e-mail alerts to Journal of Quaternary Science and receive the latest tables of contents immediately upon publication [1]http://www.interscience.wiley.com/journal/jqs ==========================