无为县夏季降水多时间尺度规律研究

Research on the multiple time scale law of summer precipitation in Wuwei County

无为县的汛期洪水主要由夏季降水形成的,为了揭示无为县夏季降水的规律和特点,服务于防汛抗旱、农作物生产等方面,采用数理统计的方法,研究夏季降水量的年际、年内的月、旬、候、日、白天、夜间、小时等长、短期结合的多时间尺度变化规律和特点,并构建夏季降水量预测模型。结果表明:无为县夏季降水量存在丰枯交替的多周期变化规律,其第一、二、三主周期对应于10、13、23年,预计2016年后夏季降水量还将处于偏多阶段并持续较长时间,但即将进入下降的阶段。年内来看,夏季降水主要集中在6月和7月,其中6月下旬和7月上旬相对较大,降水量从6月1日起逐渐增加,至7月4日达到峰值后逐渐减少。近10年夏季降水集中度从6月向7月推移,自6月至8月,降水集中度从上午向下午、夜间推移,6月份的6-7时、7月份的5-6时和15-18时、8月份的17-18时和20-21时等时段降水集中度较大。

The floods in Wuwei County are mainly consist of summer precipitation. In order to reveal the laws and characteristics of summer precipitation in Wuwei County for controling flood,reliefing drought and increasing crop production,the authors used the mathematical statistics method to study the laws and characteristics of summer precipitation change on multiple time scales including interannual,monthly,ten-day period,pentad,daily,daytime,nighttime,hourly,established a model to predict the precipitation in summer. The results demonstrated that there was a multi-cycle change law in the alternating current of abundant water and dry water in Wuwei county in summer precipitation. The first,second and third main periods are 10,13 and 23 years,respectively. The summer precipitation is expected to be much rainfall stage and continue for a long time after 2016,but it is about to decrease. Within the year,the summer precipitation in Wuwei mainly concentrated in June and July,of which the last ten-day period of June and the first ten-day period of July took larger proportion. The precipitation presented a gradual increase from 1 st,June,which peaked on 4 th July and took a downturn afterwards. The concentration of summer precipitation in the past 10 years has shifted from June to July. From June to August,precipitation concentration has shifted from morning to afternoon and evening. Larger concentration of precipitation appeared between 6-7 o’clock in June,5-6 o’clock and 15-18 o’clock in July,17-18 o’clock and20-21 o’clock in August,respectively.