REGULATION AND AUTOMATION OF CROSS DATING OF TREE-RING CHRONOLOGIES IN DENDROCHRONOLOGICAL STUDIES
V. A. Oskolkov, R. S. Moritz, V. I. Voronin, N. N. Michurin
Siberian Institute of Plant Physiology and Biochemistry, Russian Academy of Sciences, Siberian Branch, Irkutsk, Russian Federation
Keywords: tree-ring chronology, cross-dating, regulation, automation, verification
Abstract
The article discusses an approach to regulating and automating cross-dating, which is an integral stage in obtaining tree-ring chronologies. The process of cross-dating the width of annual rings, although it is widely used and can be produced using software tools, is still not fully regulated and depends on subjective factors. The classical approach to cross-dating is based on the selection of one or more individual tree-ring chronologies (ITRC) as reference, and sequential dating of the remaining series relative to the selected ones. This approach has a number of restrictions. Our approach actually repeats the classical cross-dating technique, but with the only difference that the main bias is towards automating the process. In this case, all ITRCs can act as references and be dated among themselves, combining into separate selections based on the correlation level. Thus, upon completion of the process, we will have many selections of well-dated ITRCs, despite the fact that the selections themselves will most likely correlate poorly with each other. The initial selection will contain ITRCs that do not correlate with each other. Analysis of correlation links within the finished selections can reveal individual ITRCs that spoil the overall signal. Such chronologies should be removed one by one, repeating the analysis of links within the selection. The simplest solution is to evaluate the correlation of each ITRC with the generalized tree-ring chronologies (GTRC) and remove the least correlating ITRC, reconstruct the GTRC and repeat the process. Verification of the “automated cross-dating” method was carried out when creating the GTRCs Мuy 1510-2015AD; Muy1 107BC-2015AD and Muy2 3919-2053BC (Muya-Kuandinskaya Basin, Buryatia). The automated cross-dating method also made it possible to significantly improve the statistical marks and quality of the generalized tree-ring chronologies.
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