摘要
利用云南省1961～2008年94个站点逐日降水资料,根据百分位法定义了不同站点的极端强降水阈值,应用EOF、线性倾向率和周期分析方法,对云南极端强降水事件频数进行了时空分布特征诊断。结果表明:云南省汛期极端强降水阈值的空间分布呈西北至东南逐渐增大的分布趋势;以百分位法定义的极端强降水事件频数和大雨及以上强降水频数的空间分布趋势,在细节上有一定差异,但均表现为从北向南逐渐递增;一致性异常分布是云南汛期极端强降水事件频数的最主要空间模态;近50 a来云南汛期极端强降水事件频数呈现弱的线性增加趋势,其中增加较明显的区域位于澜沧江、红河的下游区域、哀牢山以西一带,而昆明大部到曲靖西部则呈现较明显的线性减少趋势;近50 a来云南汛期极端强降水事件存在2～3 a的振荡周期。
Based on daily precipitation data of 94 stations in Yunnan during 1961-2008,extremely heavy precipitation threshold for each station was determined according to the 95th percentiles,and the temporal and spatial distribution of frequency of extremely heavy precipitation events in flood season（May to October） in recent 50 years was diagnosed by using principal component analysis,linear trend and power spectral density analysis method.The results show that the threshold of extremely heavy precipitation events in Yunnan in flood season increased from northwest to southeast;Frequency of extremely heavy precipitation events according to the 95th percentiles and rainfall more than 25 mm had little difference in spatial distribution,but both increase from north to south;A consistent anomaly distribution was the main spatial mode for frequency of extremely heavy precipitation events in flood season in Yunnan;The frequency of extremely heavy precipitation events in flood season presented a weak linear increasing trend,especially obvious in the lower reaches of the Lancang River and the Red River,and west part of the Ailaoshan Mountain,but a linear decreasing trend from Kunming to the west part of Qujing.Meanwhile there was an oscillation cycle of 2-3 years about extremely heavy precipitation events in Yunnan in recent 50 years.
出处
《干旱气象》
2012年第1期15-20,共6页
Journal of Arid Meteorology
基金
云南省气象局气候变化研究专项(Qh201101)
国家自然科学研究基金(U0933603)资助
关键词
极端强降水事件
时空分布特征
汛期
云南
extremely heavy precipitation events
spatial and temporal distribution
flood season
Yunnan
