UTLIZING TREE RING CHRONOLOGIES TO RECONSTRUCT 200 YEARS' MOISTURE INDEX IN YISHAN, SHANDONG PROVINCE
1998, 17 (2):
Tree ring chronologies are a major source of paleoclimatic information in China, especially in Northwest China. For some reasons, there are seldom studies about the tree ring in eastern China.In this paper the major tree ring chronology (1750~1992) in Yishan, Shandong Province, was analyzed by running program ARSTAN. The response surfaces of tree ring and climate indicate that growth of tree ring in Yishan mountain is nonlinear correlated with precipitation and temperature.It is unreasonable to reconstruct climatic variables separately using traditional methods. The reconstructed moisture index (
P/T) during May to August, in which both temperature and precipitation influence the tree ring growth, was estimated from response function and regression model. The relationship between tree ring and moisture index (May to August) is obvious. The predictive equation (
X+5.65) was obtained from a linear regression model, where
Y is predicted value of moisture index,
X is tree ring width index. As a result, the local moisture index in 1750 AD at Yishan, Shandong Province, was reconstructed based on tree ring chronologies.For verification of the reliability of the reconstructed moisture index in Yishan area, the dry years were selected from document data, which were used to compare with the years with the small reconstructed moisture index.From 1750 to 1960, there are 32 dry years in document data, which were coincided with the 24 small moisture index years (1758,1768,1774,1778,1786,1805,1814,1825,1837,1838,1856,1860,1876,1877,1878,1899,1907,1917,1920,1925,1927,1948,1952,1959). There are 75 percent correct predictions, which indicates that the reconstructed results were reliable.
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