Tree-Ring-Based Summer Temperature Minimum Reconstruction for Taboshar, Sogd Province, Tajikistan, Since AD 1840: Linkages to the Oceans

Abstract

Despite the ecological importance of forest tree species, our study was motivated by scarce data on dendrochronology studies limited to the northwestern part of Tajikistan due to lack of access to such a part of the country which is difficult to access. Current studies on Junipers in the northwestern part of Tajikistan identified that tree ring-based climate reconstruction is possible.Cores of Juniperus Turkestanica from Taboshar area, Sogd province were developed into 176-year tree-ring width chronology. In the current study a summer (June-September) minimum temperature reconstruction spanning AD 1840-2016 was developed, which can explain 30.0% of the instrumental variableness for the period of 1940 . Five warmest (1856 -1866 , 1869 -1871 , 1907 -1916 , 1923 -1935 , 1988 and four coldest time periods (1840-1855, 1872-1906, 1917-1922, 1940-1984) were identified. The developed reconstruction coincides with cold and warm periods with prior investigations from tree-rings in China, Mongolia, Kyrgyzstan, Kazakhstan and Tajikistan. Spatial correlation analysis with the gridded minimum temperature data shows that the temperature reconstruction covers geographical representation over High Asia. Significant correlation was found between temperature reconstruction with summer SST, which suggests strong linkages of regional temperature variability with IndianOcean climate system. The obtained spectral peaks from the spectral analysis of the summer temperature reconstruction were significantly at 84.7-year (90%), 2.9-year (99%), 2.6-year (99%), 2.5-year (99%), 2.4-year (99%) and 2.2-year (99%).

Understanding the Representativeness of Tree Rings and Their Carbon Isotopes in Characterizing the Climate Signal of Tajikistan

“…In addition, the MS and Std. Dev of the TRW chronology were similar to other TRW chronologies near these seven sample sites in Tajikistan [74]. Besides MS and EPS, the common variance of all the detrended series accounted for 40.6% of the total variance, indicating that juniper tree growth at the seven sites was influenced by similar factors.…”