现代环境研究室知识库

We reconstructed the first Palmer Drought Severity Index (PDSI) in the Taihang Mountains, north China from 1873 to 2008, based on ring width of the Chinese Pine (Pinus tabulaeformis Carr). The reconstruction can explain 43.2 % of the PDSI from instrument record during the calibration period (1955-2005). The PDSI variability was relatively stable before the twentieth century. However, it became more variable and persistent during the twentieth and early twenty-first century. Persistent long dry intervals were found in 1920-1931, 1973-1982 and 1992-2001, and the wet intervals were identified in 1944-1965 and 2004-2008. Comparing with the 1920s, the dryness of the 1970s and 1990s were more intense and the 1990s ranked the most severe drought for the whole reconstructed period in the Taihang Mountains. After a decreasing trend since the 1950s, the PDSI shows increasing tendency after 2000, demonstrating a better moisture condition in recent years in the studied area. Comparisons of our reconstruction with nearby dry/wet index and other tree-ring-based PDSI reconstruction showed high consistency in dry (wet) periods, showing similar dry-wet regimes around the sampled site, which was also further proved by the spatial correlation analysis. This reconstruction is also highly correlated with the East Asian Summer Monsoon (EASM) index, suggesting the reconstructed PDSI could be used to indicate the strength of EASM. Spectral analysis revealed significant peaks at 2.05, 2.07, 2.65, 3.75, 10 and 60 years, implying the influence of larger circulation system (such as ENSO, PDO and NAO) and solar activity on local climate.