Tree ring based drought variability in Northwest Tajikistan since 1895 AD

• Published in: Journal of arid land Vol. 12; no. 3; pp. 413 - 422
• Main Authors: Yang, Meilin, Yu, Yang, Zhang, Haiyan, Wang, Qian, Gan, Miao, Yu, Ruide
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.05.2020; Springer Nature B.V; State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China%State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; School of Environment and Material Science, Yantai University, Yantai 264005, China
• Subjects: Arid regions; Arid zones; Chronology; Climate change; Climate change and environmental response in arid lands of Central Asia; Climate models; Climatic data; Correlation analysis; Drought; Earth and Environmental Science; Environmental changes; Evapotranspiration; Geography; Growth; Hydrologic data; Physical Geography; Plant Ecology; Precipitation; Reconstruction; Sequencing; Spatial analysis; Sustainable Development; Tree rings; Trees; Variance analysis; Water management; Water resources; Water resources management; Tajikistan; tree ring width; Pamir region; chronology; drought; standardized precipitation evapotranspiration index (SPEI); Juniperus turkestanica
• ISSN: 1674-6767; 2194-7783
• DOI: 10.1007/s40333-020-0062-1

Determining the mechanisms controlling the changes of wet and dry conditions will improve our understanding of climate change over the past hundred years, which is of great significance to the study of climate and environmental changes in the arid regions of Central Asia. Forest trees are ecologically significant in the local environment, and therefore the tree ring analysis can provide a clear record of regional historical climate. This study analyzed the correlation between the tree ring width chronology of Juniperus turkestanica Komarov and the standardized precipitation evapotranspiration index (SPEI) in Northwest Tajikistan, based on 56 tree ring samples collected from Shahristan in the Pamir region. Climate data including precipitation, temperature and the SPEI were downloaded from the Climate Research Unit (CRU) TS 4.00. The COFECHA program was used for cross-dating, and the ARSTAN program was used to remove the growth trend of the tree itself and the influence of non-climatic factors on the growth of the trees. A significant correlation was found between the radial growth of J. turkestanica trees and the monthly mean SPEI of February–April. The monthly mean SPEI sequence of February–April during the period of 1895–2016 was reconstructed, and the reconstruction equation explained 42.5% of the variance. During the past 122 a (1895–2016), the study area has experienced three wetter periods (precipitation above average): 1901–1919, 1945–1983 and 1995–2010, and four drier periods (precipitation below average): 1895–1900, 1920–1944, 1984–1994 and 2011–2016. The spatial correlation analysis revealed that the monthly mean SPEI reconstruction sequence of February–April could be used to characterize the large-scale dry-wet variations in Northwest Tajikistan during the period of 1895–2016. This study could provide comparative data for validating the projections of climate models and scientific basis for managing water resources in Tajikistan in the context of climate change.