金华市水资源的丰枯变化特征

金华市属于湿润地区,但水荒问题已经悄然逼近。根据1470~2003年534年的历史和实测资料分析,得出了金华市水资源丰枯变化的频数特征、持续特征、周期特征、响应特征和风险特征,这对金华市社会经济建设具有一定的指导意义。

Characteristic of High and Low Water Resources Change in Jinhua City

In order to gain reliable and complete precipitation serials, textual research is made to local records such as Jinhua Official Records and Quzhou Official Records respectively,then based on the precipitation data at Jinhua Station from May to September during 1980-2003,protracted the precipitation year at Jinhua Station to 2003.Based on the analysis of the historical and measured data in 1470-2003,the characteristics of high and low water resources change in Jinhua City can be achieved as follows:(1) The 17th century is the frequent period with high and low water resources change in Jinhua City,16421671 of them is the most concentrated time of high and low water years,and there is the special high and low water years of 16 times in 30 years.(2) The greater the high and low water resources change,the shorter the sustained years,the fewer the times it appears.There is 8 years in the medium water year of the longest sustained time(in 1893-1900).(3) There are varied cycles of high and low water resources change,and the cycle change of 20-22 years is very clear.The curve of high and low water change has descended to the lowest point currently and started rising gradually,therefore within the future 20 years,it will keep on rising,namely turning from high water predominated stage to low water predominated stage.(4) The high and low water change responds evidently to sunspot activity and El Nino event.The anomalous annual precipitation of 3 years average at Jinhua Station around the transformation year of the magnetic cycle is all positive.The years of annual precipitation R>1550 mm at Jinhua Station mainly appear in the same or next year of El Nino.(5) The May-September precipitation occurring once 5 years in low water year in Jinhua City is only 604 mm and that occurring once 10 years is only 550 mm.