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Arid Land Geography ›› 2024, Vol. 47 ›› Issue (6): 909-921.doi: 10.12118/j.issn.1000-6060.2023.400

• Climatology and Hydrology • Previous Articles     Next Articles

Reconstruction of the minimum temperature over the past 202 years based on tree rings of Picea crassifolia in the Helan Mountains

ZHANG Jing(), MA Long(), LIU Tingxi, SUN Bolin, QIAO Zixu   

  1. College of Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, Inner Mongolia, China
  • Received:2023-08-03 Revised:2023-09-03 Online:2024-06-25 Published:2024-07-09
  • Contact: MA Long E-mail:zhangjing2292024@163.com;malong4444333@163.com

Abstract:

Under the influence of global warming, profound changes are occurring in the global hydroclimatic system. Understanding the long-term climate patterns in monsoon and nonmonsoon transitional zones is crucial owing to their complex and diverse climates. Utilizing 66 tree-ring cores from 36 Picea crassifolia trees, a dendrochronological chronology from 1798 to 2016 (219 years) was established for a typical area in the transitional zone (Helan Mountains region, northwest China). The Pearson correlation method was used to analyze the relationship between tree-ring widths and local climatic factors. The results show that: (1) The radial growth of Picea crassifolia closely correlates with the area’s annual average minimum temperature (R2=0.638, P<0.001). A linear regression equation was used to reconstruct the annual average minimum temperature series for Helan Mountains from 1815 to 2016, with a reduction error and coefficient of efficiency of 0.808 and 0.482, respectively. (2) The reconstructed series generally indicates lower temperatures in the 19th century, consistent with the globally recognized “Little Ice Age”. From the late 19th century, temperatures gradually increased, showing significant warm periods and extremely warm years, with three abrupt temperature shifts in the 1850s, 1890s, and 1990s. (3) Morlet wavelet analysis shows the periodic distribution characteristics of 6 a, 21 a and 46-56 a. Southern Oscillation, Pacific Decadal Oscillation, and Atlantic Multidecadal Oscillation are the driving factors behind these periodic changes. (4) Large-scale spatial correlation analysis indicates that the reconstructed temperature series represents the temperature variations well in large regions like most of Inner Mongolia and Ningxia. The reconstructed annual average minimum temperature series for this typical monsoon and nonmonsoon transitional zone reveals its climatic characteristics, providing a reference for global climate change research.

Key words: dendrochronological chronology, minimum temperature reconstruction, climate change, monsoon and non-monsoon transition zone, Helan Mountains