date: Tue, 4 Jul 2000 10:24:01 +0700
from: "Sukachev Forest Institute" <institute@forest.akadem.ru>
subject: from Prof.Vaganov
to: "Briffa Keith" <K.Briffa@uea.ac.uk>

   Dear Keith
        Draft of paper : Briffa K.R. et al. <Tree-ring width and density data around the
   Northern
   Hemisphere: part 1, local and regional climate signal>
        I have no significant remarks over this rich of statistical analysis and complicated
   paper. Only one
   short note to page 7-8 where in first paragraph telling about weaker TRW climatic signal.
   There are
   some earlier publications (for example, Hughes et al, 1999) where the highest correlation
   (0,84)
   between TRW and temperature is shown. The weakness, probably, related to heterogeneity of
   sites
   (northern timberline and more southern) for large sectors you used and shifting the highest
   response to
   earlier summer (spring) month towards to south. TRW is highly correlated (R=0,97-99) to
   tracheid
   production, and in high latitudes the most of tracheids are produced by cambial zone in
   first part of a
   season, so mainly response to the starting date of beginning of a season (Vaganov,
   Shashkin, 2000).
   Towards to the south, the starting dates are shifting to early date - it is obvious.



   Draft of paper: Briffa et al. <Low-frequency temperature variations from a northern
   tree-ring-density
   network> (sorry, too many formal statistics for me).
        Only some minor notes could be made.
   1.  Third paragraph in part 2 (page 5). Concerning Fig.3. - what is the differences between
   thin and
   dashed smoothed lines in individual curves (one is age, another is?). Maybe indicate it in
   text rather
   in figure captions.
   2.  Last paragraph in part 3. You may mentioned the similar results about warm 15-th and
   coolest late
   17-th centuries which are shown in temperature reconstruction based on supra-long Taymir
   chronology (Naurzbaev, Vaganov, 2000).
   3.   Last paragraph in part 4. The main similar cycles were revealed in analysis of Taymir
   two-millennia
   chronology (ibid).



   There are some relevant references (only ours):
   1.  Vaganov E.A., Shiyatov S.G., Mazepa V.S. Dendroclimatic Study in Ural-Siberian
   Subarctic.
   Novosibirsk, Nauka, 1996, - 246 pp. (in Russ.).
             Annual maps of June-July temperature anomalies over Siberian Subarctic were
   constructed
   based on 61 local tree-ring chronologies. There is an increasing of frequency of warm
   summers for the
   whole Siberian Subarctic in 20-th century.



   2.  Vaganov E.A., Shiyatov S.G., Hantemirov R.M., Naurzbaev M.M. Summer temperature
   variations
   in high latitudes of Northern Hemisphere during last 1,5 millennia: a comparison analysis
   of tree-ring
   and ice core data. Doklady AN, 1998, 338(5): 681-684 (in Russ. and Engl.).
             Coincidence of long-term summer temperature changes in different regions of
   Siberian Subarctic
   during last 1,5 thousand years is shown. These changes agree well with Greenland's ice core
   data.



   3.  Vaganov E.A., Hughes M.K. Tree rings and global carbon cycle. Problems of Ecological
   Monitoring and Ecosystem Modelling, 2000, 17: 36-48 (in Engl.).
           A review of application of various tree-ring data (width, density, fire scars,
   isotopic ratio etc.) to
   evaluate of certain parameters of carbon cycle in forest ecosystems.



   4.  Naurzbaev M.M., Vaganov E.A. Variations of early summer and annual temperature in the
   East
   Taymir and Putoran over last two millennia inferred from tree-rings. J.Geophy.Res., 2000,
   105(6):
   7317-7327 (in Engl.).
           Reconstructed temperature variations agree well with other indirect proxy data and
   reveal that
   warmth of Medieval Warm Period is closely to warmth in last century. Some cyclic components
   are
   significantly exist in temperature variations: double secular (around 180 years), secular
   (78-90 years)
   and intrasecular (44, 28, 11 and 6,7-6,9 years). Long coolest periods were in the end of 13
   century and
   in 16-17 centuries.



   5.  Vaganov E.A., Briffa K.R., Naurzbaev M.M., Schweingruber F.H., Shiyatov S.G., Shishov
   V.V.
   Long-term temperature changes in Arctic region. Doklady AN, 2000, (accepted) (in Russ. and
   Engl.).
            Similarity of long-term summer temperature changes in high latitudes of Northern
   America and
   Asia over last 600 years, and significant correlation of its variations to volcanic sulfur
   components
   (negative) and solar irradiation (positive). Some disagreement between two large sector of
   Arctic
   region revealed for cool period in 19-th century: in Asian sector cool period occur earlier
   than in North
   America and Greenland.



   6.  Vaganov E.A., Shashkin A.V. Tree-ring Growth and Structure in Conifers. Novosibirsk,
   Nauka,
   2000, - 238 pp. (will be published in September) (in Russ.).



   Thanks, Gene.