400多年来中国东部旱涝型变化与太平洋年代际振荡关系
摘要
We analyzed dryness/wetness indices at 55 sites across eastern China (east of 105°E) for the period AD 1600-2012 using the Ensemble Empirical Mode Decomposition (EEMD) method to investigate decadal-to-centennial timescale variations of dry/wet patterns in this region and their relationship with the Pacific Decadal Oscillation (PDO). Empirical Orthogonal Function (EOF) analysis shows that the most important regional dry/wet pattern is a monopole (consistently dry or wet throughout eastern China), with a center of variability in northern China. The southern-flood-northern-drought (SFND) pattern represents a secondary type of variability for the historical period; however, this tended to intensify and has become the dominant pattern over the 20th century. Multidecadal SFND events, such as that prevailing from the late 1970s to the early 21st century, have rarely occurred during the last 413 years. Multi-decadal dry/wet variations in northern China exhibit positive correlation with an ensemble mean PDO index of various reconstructed indices throughout this historical period.