摘要
应用福建省66 站1961-2012 年逐日降水资料,基于前汛期降水定量化指标,揭示福建前汛期降水强度的多尺度特征,着重分析前汛期降水强度的低频变化特征.分析结果表明：（1） 福建省前汛期降水强度在20 世纪70 年代中期、90年代初期发生了由强到弱和由弱到强的两次明显突变,突变点为1976 年和1991 年.（2） 在前汛期降水偏弱的年代际背景下（20 世纪70 年代中期-90 年代初期）,前汛期降水强度年际波动相对较小;而在强的年代际背景下（20 世纪60 年代-70 年代中期和20 世纪90 年代初期至今）,前汛期降水强度的年际波动相对剧烈,尤其2000 年以来,福建前汛期降水极端事件明显增多,持续性强降水过程多发,且强度偏强.（3） 福建前汛期降水强度的季节内振荡明显,降水强度与低频变化的强度成正比,即前汛期降水强度偏强（弱）年份,其低频变化信号较（不）显著.（4） 前汛期降水较强的年份有75%出现显著的低频信号,且低频周期较稳定,低频周期可分为30~60 d、20~30 d 和10~20 d;25%的年份低频周期出现明显的调整.
Based on quantitative evaluation index, we analyze the day-to-day precipitation data during 1961-2012 from 66 observation stations in Fujian province in order to reveal the multi-scale features of rainfall intensity on the respect of low-frequency characteristics during the pre-flood season. The analysis results show that(1) There were two inter-decadal drifts in the pre-flood season rainfall intensity; one was from strong to weak in the middle of 1970 s, and the other was from weak to strong in the early 1990 s, with the phase change point at years of1976 and 1991.(2) During the weak inter-decadal period(from mid 1970 s to early 1990s), the variation of inter-annual rainfall intensity was relatively low, while during the strong inter-decadal period(from 1960 s to mid 1970 s and from early 1990 s to the present), the inter-annual fluctuation of rainfall intensity was relatively high. In particular, since 2000 extreme precipitation events have clearly increased, and the persistent heavy rain events occurred more often.(3) The inter-seasonal oscillation of rainfall intensity in the pre-flood season has become evident, and the intensity of the precipitation is proportional to the intensity of low-frequency variation. Namely, during the strong phase years,the low-frequency signals were more evident, and vice verse.(4) In 75 percent of all the strong phase years, significant low-frequency signals are detected, which had three kinds of stable cycles of 30~60 days, 20~30 days and 10~20 days; while in the other 25 percent of the years it is shown an adjustment process in the low-frequency cycle.
出处
《暴雨灾害》
2014年第3期297-303,共7页
Torrential Rain and Disasters
基金
福建省科技厅科技计划重点项目(2011Y0008)
国家公益性(气象)行业专项(201306067)
关键词
前汛期降水强度
定量化指标
多尺度特征
低频变化
pre-flood season rainfall intensity
quantitative evaluation index
multi-scale features
low-frequency variation
