摘要
利用重庆1961—2006年33个台站汛期(5—9月)逐日降水资料,首先定义了不同台站的极端降水阈值,然后统计出不同台站近46 a逐年汛期极端降水事件的发生频次,并进行时空分布特征分析。结果表明:重庆汛期极端降水事件发生频次的多寡很大程度上影响着汛期总降水量的大小。一致性异常分布特征是重庆汛期极端降水事件发生频次的最主要空间模态;重庆汛期极端降水事件发生频次的空间分布可分为5个主要区域。从长期变化趋势来看,Ⅰ、Ⅲ和Ⅳ区为很弱的减少趋势,Ⅱ区表现为很弱的增加趋势,Ⅴ区则表现为相对较强的增加趋势。最大熵谱估计分析表明,近46 a来汛期极端降水事件发生频次各区之间的周期振荡不太一致,均存在2年左右的年际变化周期,不同的分区主要还存在着5年的年际变化周期和11年、15年左右的年代际变化周期振荡。
Based on the daily precipitation data of flood season （May to September） in 1961-2006 from 33 stations in Chongqing, we firstly determined the extreme precipitation threshold values for each of the stations, then counted the frequency of extreme precipitation events in the flood season and analyzed their temporal and spatial characteristics. The results show that the extreme precipitation event frequency greatly affects the amount of total precipitation in the flood season. Consistent anomaly distribution is the main spatial model of frequency of extreme precipitation events in Chongqing. The spatial distribution of extreme precipitation event frequency can be divided into five main regions. From the long-term change, Regions Ⅰ, Ⅲ and Ⅳ display very weak declining trends. Region Ⅱ shows very weak increasing trend. Region V shows a relatively strong increasing trend. The Maximum Entropy Spectral Estimation analysis shows that the periodic oscillations of these regions are not well consistent in the recent 45a. All regions are showing an interannual variation of about 2 years in period. Depending on the region, there mainly exists an interannual variations of 5-year period and interdecadal variations of 11-year and 15-year periods.
出处
《热带气象学报》
CSCD
北大核心
2009年第4期475-482,共8页
Journal of Tropical Meteorology
基金
中国气象局业务建设项目"三峡气候效应监测评估研究"资助
关键词
气候学
极端降水
旋转主成分
重庆
climatology
extreme precipitation
rotated principal component analysis
Chongqing
