Reconstruction and Analysis of Precipitation in the Hutubi River Basin on the Northern Slope of the Tianshan Mountains during the Last 313 Years

Abstract

In this study,several tree-ring chronologies were established based on tree-ring samples collected from the Hutubi River Basin,Xinjiang.A single correlation calculation revealed that the tree-ring chronologies were significantly correlated with the precipitation from August to the following July,and that the maximum correlation coefficient observed was 0.484.Based on the SRKt(STD),XRKt(STD) and KYSt(STD) tree-ring chronology series,the precipitation series from August to the following July during the last 313 years were reconstructed with an explained variance of 41%.A crossing-test of these data indicated that the reconstructed results were reliable.The results of the analysis of the precipitation series were as follows:(1) There were 7 rainy stages and 6 drought stages in the Hutubi River Basin during the last 313 years;(2) There were 168 normal years,67 dry years,72 damp years,5 drought years and 1 rainy year in the last 313 years.Specifically,the rainy stage occurred from 1992 to 2003,during which time the average annual precipitation was 203.3 mm,which was 15.6% higher than the average for the last 42 years.In addition,the drought stage occurred from 1785 to 1798,during which time the average annual precipitation was 160.1mm,or 8.9% lower than the average for the last 42 years;(3) The reconstructed precipitation series in the Hutubi River Basin from August to the following July for the last 313 years revealed that there were significant precipitation quasi-periods of 2.08~2.97,3.78~4.52,29.7 and 34.7 years.In addition,precipitation mutations occurred in 1722,1741,1799,1858,1886,1921 and 1957,respectively,with the most significant mutation occurring in 1886.