date: Mon, 12 Apr 1999 13:06:05 -0400 (EDT) from: mann@snow.geo.umass.edu subject: perspectives to: k.briffa@uea.ac.uk Dear Keith, THanks for your message--I will look forward to receiving it (tell Tim to FAX it to the FAX below ASAP. I leave also for a week for EGS April 16-21st, and will be busy for a couple days upon my return, so the sooner the better). I have, as mentioned in previous message, incorporate the correct re-worked version of your n. hem density series into the featured IPCC plot comparing the different estimates, and the comparison is indeed much better. Will let you know where you can download the revised figure for your own inspection... With regard to the question you asked, the composite of all of the series which make up Gordon's NOrthern treeline was used. Admittedly, only a handfull go back before 1500, and only one all the way back to AD 1400. So the "sampling" contributing to the NT composite does decrease back in time. What is remarkable is that, even with this limiation, the similarity between the low-frequency signal in the NT composite and the ITRDB PC #1 is stunning---until the 19th century. This is telling us something profound, I believe... Anyways, will look forward to seeing the piece and the sooner Tim can get it to me, the more likely I can return some comments before I have to leave for 1 week+ on friday morning. Thanks again, mike _______________________________________________________________________ Michael E. Mann ________Current_____________________________Starting Fall 1999_________ Adjunct Assistant Professor | Assistant Professor Department of Geosciences | Dept. of Environmental Sciences Morrill Science Center | Clark Hall University of Massachusetts | University of Virginia Amherst, MA 01003 | Charlottesville, VA 22903 _________________________________|_____________________________________ e-mail: mann@geo.umass.edu; memann@titan.oit.umass.edu (attachments) Phone: (413) 545-9573 FAX: (413) 545-1200 http://www.geo.umass.edu/climate/mike