Multi-Proxy Reconstruction of Drought Variability in China during the Past Two Millennia

作者：Yang, Bing; Lai, Chengguang; Chen, Xiaohong^*; Singh, Vijay P.; Wang, Jiawen

来源：Water, 2022, 14(6): 858.

DOI：10.3390/w14060858

• self-calibrating Palmer drought severity index
• meteorological drought
• reconstruction
• proxy record
• multi-scale variation
• rotated empirical orthogonal function

Drought imposes serious challenges to ecosystems and societies and has plagued mankind throughout the ages. To understand the long-term trend of drought in China, a series of annual self-calibrating Palmer drought severity indexes (scPDSI), which is a semi-physical drought index based on the land surface water balance, were reconstructed during AD 56 similar to 2000. Multi-proxy records of tree-ring width and stalagmite oxygen isotope 6 18 0 were used for this reconstruction, along with random forest regression. The spatiotemporal characteristics of the reconstruction results were analyzed, and comparisons were made with previous studies. Results showed that (1) China witnessed a drought-based state during the past 2000 years (mean value of scPDSI was -0.3151), with an average annual drought area of 85,000 km 2 ; 4 wetting periods, i.e., the Han Dynasty (AD 56 similar to 220), the Tang Dynasty (AD 618 similar to 907), the Ming Dynasty (AD 1368 similar to 1644), and the Qing Dynasty (AD 1644 similar to 1912); and 2 drying periods, i.e., the Era of Disunity (AD 221 similar to 580) and the Song Dynasty (AD 960 similar to 1279). (2) Three different alternating fluctuation dry-wet modes (i.e., interannual, multidecadal, and centennial scales) in China were all significantly (p-value < 0.001) correlated with the amplitude and frequency of temperature in the Northern Hemisphere. (3) According to the spatial models disassembled from the rotated empirical orthogonal function, China was divided into nine dry-wet regions: northwestern China, Xinjiang, southwestern China, southeastern China, the Loess plateau, central China, southwestern Tibet, eastern China, and northeastern China. (4) The random forest (RF) was found to be accurate and stable for the reconstruction of drought variability in China compared with linear regression.

• 单位
  中山大学