August to July Precipitation from Tree Rings in the Forest-Steppe Zone of Central Siberia (Russia)
The goal of this research report is to describe annual precipitation reconstruction from Pinus sylvestris trees on three sites in the Abakan region, located in the Minusinsk Depression, at the confluence of the Yenisei and Abakan Rivers, Russia. The study was performed during the 4th annual international summer course “Tree Rings, Climate, Natural Resources and Human Interaction” held in Abakan, 5-19 August 2013. The reconstruction, for the 12-month total precipitation ending in July of the growth year, is based on a reliable and replicable statistical relationship between precipitation and tree-ring growth, and shows climate variability on both interannual and interdecadal time scales. The regional tree-ring chronology accounts for 56% of the variance of observed annual precipitation in a linear regression model, with the strongest monthly precipitation signal concentrated in May and June of the current growing season. Composite 500 mb height-anomaly maps suggest that the tree-ring data from this site, supplemented by other regional tree-ring data, could yield information on long-term atmospheric circulation variability over the study area and surrounding region.ABSTRACT
Locations of tree-ring sites (▴) and climate station (•).
(A) Tree-ring residual chronology of Pinus sylvestris along with number of trees; (B) Time series plot of reconstructed PA-CJ precipitation; (C) Five-year moving average of reconstructed PA-CJ precipitation. Values are plotted at the center of each 5-year period. Uncertainty values are shown at 80% confidence interval.
Program Seascorr summary of seasonal climatic signal in the residual chronology data. Climatic variables are monthly precipitation and temperature of Minusinsk meteorological station. (Top) Correlation of tree-ring variable with monthly, 3-month total, 6-month total, and 12-month total precipitation for ending months from August preceding the growth year through September of the growth year. (Bottom) Partial correlations (controlling for precipitation) of tree-ring variable with monthly average temperature. Colors indicate Monte-Carlo-derived significance of correlation or partial correlation (Meko et al. 2011) for α-levels 0.01 and 0.05. Analysis period is tree-ring years 1937–2012.
Composite map of difference in May-June 500 mb height anomalies in dry years and wet years. Years for composites are among driest (or wettest) ten years both in the precipitation reconstruction and in May-June observed precipitation at Minusinsk. Dry years are 1965, 1964 and 2012. Wet years are 1970, 1995 and 2003. Anomalies (color bar) are departures (m) from 1981–2010 climatology. Map drawn with online mapping tool from the NOAA Earth System Research Laboratory (http://www.esrl.noaa.gov/psd/cgi-bin/data/getpage.pl).
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