近50a长江中下游不同量级暴雨的年代际变化特征

利用1966—2015年中国地面气候资料数据集降水数据,对长江中下游地区春、夏、秋三季不同量级暴雨的年代际变化特征进行了研究。结果表明,暴雨在各季节变化特征明显不同,不同量级间也存在明显差异。暴雨在春秋季变化平稳,但在夏季呈现1990s频发,2000年之后少发的特征,并存在准20 a周期变化。大暴雨则在近30 a来呈现频发的特征,其中春季大暴雨在2010年之后显著增加,秋季大暴雨则在2000年之后明显增加。特大暴雨发生概率很小,但夏季特大暴雨在1990s之后一直呈现频发的趋势,并表现为准32 a的周期变化特征,秋季特大暴雨在2000年之后明显频发。大暴雨、特大暴雨在各季节均表现为近十几年来显著增加的趋势。暴雨和大暴雨均存在明显年代际跃变,这种跃变在暴雨、大暴雨频发的区域增幅更为显著。

Analysis on the inter-decadal variation features of rainstorms with different magnitudes over the middle and lower reaches of Yangtze River in recent 50 years

By using the precipitation data from the data set of ground climate in China during 1966-2015, the inter-decadal variation features of rainstorms with different intensities over the middle and lower reaches of Yangtze River in spring, summer, autumn and winter were analyzed. Results show that the rainstorms presented different features in different seasons, and there were also significant differences among rainstorms of different magnitudes. Variations of rainstorms were stable in spring and autumn, but in summer, rainstorms appeared frequently in the 1990s, and they were less frequent after the 2000, and they displayed quasi-20-year periodic changes. Heavy rainstorms occurred frequently in the recent 30 years. In spring, the occurrence of heavy rainstorm increased obviously from 2010, and in autumn, it increased obviously from 2000. The probability of mega-storms was very small, but the heavy rainstorms in summer had been appearing frequently after the 1990s, and they were characterized by quasi-32-year periodic changes. The mega-storms in autumn were obviously frequent after 2000. The heavy rainstorms and mega-storms both had the trend of significant increase in all seasons in recent decades. Rainstorms and heavy rainstorms both displayed obvious inter-decadal jumps, this kind of jump displayed more significant increases in areas where rainstorms and heavy rainstorms occured frequently.