TREE-RING RECORDS OF DROUGHT AND WETNESS VARIATIONS IN SOUTHEASTERN UZBEKISTAN SINCE 1780
Determining the controlling mechanisms of drought and wet conditions will enhance our understanding of climate change over the past century and is of great significance for studying climate and environmental changes in the arid regions of Uzbekistan.This study is based on 38 tree core samples collected from 25 Juniperus turkestanica trees in southeastern Uzbekistan,establishing a reliable chronology from 1780 to 2014.It analyzes the correlation between the tree-ring width index of Juniperus turkestanica and the monthly Standardized Precipitation Evapotranspiration Index(SPEI)in the study area.The results indicate that during the growing season,precipitation and temperature are the main limiting factors for radial tree growth,with precipitation promoting growth and temperature inhibiting it.Correlation analysis between the standard chronology(STD)and combined meteorological factors of multiple months showed a highly significant correlation between the average SPEI from June of the previous year to May of the current year and the STD(R=0.643,P＜0.01).Based on this analysis,a linear regression model was established,explaining 41.3％of the variance.The reliability and stability of the reconstructed equation were validated using the leave-one-out method,with a reduction of error(RE)value greater than 0 and a product mean test(PMT)value of 7.63.The reconstructed SPEI6-5 sequence for 1780～2014 shows that the study area experienced 8 extremely dry years and 4 extremely wet years over the past 235 years.The drought and wet conditions in the study area may be influenced by atmospheric circulation factors,including the Interdecadal Pacific Oscillationt and the North Atlantic Oscillation,which regulate climate and hydrological changes through water vapor flux.This study provides data references for the management and scientific utilization of water resources in southeastern Uzbekistan in the context of climate change.
tree-ringSoutheastern UzbekistanSPEI reconstructionNAO and IPO
NETL
NSTL
万方数据
