山东省夏季降水的年代际变化和年际变化

摘要

Based on the 7-station observation in Shandong Province and other datasets, interdecadal and interannual variabilities of summer rainfall in Shandong Province are analyzed. The result showed that summer rainfall underwent a pronounced interdecadal variability, with more rainfall from 1950s to the late 1970s and less rainfall from the late 1970s to the beginning of the 21st century. After the late 1970s, there occurred a transition for the Paciifc decadal oscillation from a negative phase to a positive one, thus leading to a decreased East Asian summer monsoon and less summer rainfall in Shandong Province. In addition, the decadal background plays a role in interannual variability of summer rainfall. During 1951—1977, there was a significantly negative correlation between summer rainfall and sea surface temperature in the tropical central Pacific (Niño4 region). After 1978, however, this relation decreased dramatically. It is also noted that summer rainfall in Shandong Province seems to have entered a more rainfall period along with a transition of PDO from a positive phase to a negative one after 2003.%基于山东省7个台站的观测资料和其他多种资料，分析了山东夏季降水的年代际和年际变化。结果表明，山东省夏季降水经历了显著的年代际变化，20世纪50—70年代末为多雨期，70年代末到21世纪初为少雨期。70年代末之后，太平洋年代际振荡（PDO）从负位相转变为正位相，东亚夏季风减弱，导致山东省夏季降水减少。此外，年代际背景还影响到山东夏季降水的年际变化。在1951—1977年期间，降水与热带中太平洋（Niño4区）海表温度呈显著负相关，但在1978年之后，这种相关关系明显减弱。值得注意的是，PDO指数在2003年之后再次由正转负，山东夏季有可能再次转变为多雨。