现代环境研究室知识库

Pinus tabulaeformis ring widths were used to reconstruct mean Palmer Drought Severity Indices (PDSIs) from May to July for each of the past 283 years for Kongtong Mountain, China. A calibration model for the period from 1940 to 2005 explains 66.4% (or 65.9% after adjusting for the loss of the degrees of freedom) of the actual PDSI variance. The reconstructed Kongtong Mountain PDSIs could be representative of the moisture conditions of the entire Loess Plateau. The reconstruction captures a severe 1927–1930 drought event that was widespread across all of northern China. After 11‐year moving average, the reconstructed Kongtong PDSI was found to compare well with other tree ring‐based temperature reconstructions from both Huanglong (in the eastern part of the Chinese Loess Plateau) and Hokkaido, Japan. This result indicates that high temperatures may be a major contributor to the severity of dryness at low frequencies. Significant 93.33‐year and approximate 2‐year cycles were observed in the Kongtong tree ring chronology.