扬州地区极端降水指标变化特征研究

Variation Characteristics of Extreme Precipitation Events of Yangzhou

极端降水是产生洪涝灾害的首要原因之一,对农业生产有着重要影响。本研究使用扬州地区日降水数据,研究了极端降水指标的年内、年际及周期性变化特征,探讨了降水频率及降水强度对总降水的影响,发现:在年内,一日暴雨、三日暴雨、五日暴雨、降水强度、中雨日数、大雨日数、暴雨日数、持续湿期、强降水量和特强降水量均呈现先增加后减小的趋势;持续干期表现为先减小后增加的趋势。在年尺度上,一日暴雨、三日暴雨、五日暴雨、降水强度、中雨日数、大雨日数、暴雨日数、强降水量、特强降水量及总降水量呈现增加的趋势;持续干期和持续湿期均呈现减小的趋势。一日暴雨存在3.8年的显著变化周期,三日暴雨、五日暴雨存在4年的显著变化周期,中雨日数、总降水量存在5.7年的显著变化周期,大雨日数、暴雨日数分别存在5.9年和5.8年的显著变化周期。降水频率变化对总降水量贡献均大于降水强度。研究结果可为扬州地区灌溉排水规划及防灾减灾提供参考依据。

Extreme precipitation is an important fact that lead to flood-waterlogging disaster and has an important impact on agricultural production.Based on the daily precipitation data in Yangzhou,this study studies the intra-annual,inter-annual and periodic variation characteristics of extreme precipitation indicators,and discusses the influence of precipitation frequency and precipitation intensity on total precipitation.It is found that:RX1 day,RX3 day,RX5 day,R10,R20,R50,SDII,CWD,R95p and R99p had increased trend and CDD had decreased trend within the year.RX1 day,RX3 day,RX5 day,R10,R20,R50,SDII,R95p,R99p and PRCTOT had increased trend,and CDD and CWD had decreased trend on the inter-annual.RX1 day had a significant 3.8 year periodicity,RX3 day and RX5 day had significant 4 year periodicity,R10 and PRCTOT had 5.7 year periodicity,R20 and R50 had 5.9 and 5.8 year periodicity.The effect of precipitation frequency on total precipitation is greater than hat of precipitation intensity.These findings might provide data for irrigation and drainage planning and disaster prevention and mitigation in Yangzhou.