辽宁省洪涝灾害规律的初步研究

根据辽宁省21个气象站点1958-2008年逐日降水观测数据,采用Z指数方法和区域旱涝等级评定,并运用Morlet小波分析和Kriging空间插值法对辽宁省近51年洪涝灾害的时空分布特征进行经验正交函数(EOF)方法对比分析。研究结果表明:从时间变化方面来看,1958-2008年间的降水变化呈波动式下降趋势,减小趋势为1.96mm/a,年际变幅比较大,且呈周期性变化,主周期约为9年,次周期约为24年和3年;从空间变化方面来看,根据EOF分析,辽宁省降水分布呈现整体一致性、东南-西北对称相反性、中部-两侧对称相反性。主体变化是由辽东南沿海向西北内陆递减;洪涝灾害区主要集中在辽北、辽中、辽西北部分地区的大、中河流的中下游平原。

Preliminary research of flood disaster regular pattern in the Liaoning province

According to 21 meteorological stations' daily precipitation data from 1958 to 2008 in Liaoning province,using the Z-index method and the reginal flood grades we made an EOF analysis of temporal and spatial characteristics of flood in Liaoning Province in recent 51 years by using Morlet wavelet and Kriging spatial interpolation.The results showed that from time variation perspective,there was a fluctuating downward trend in precipitation,in which the annual amplitude oscillated sharply,it had a decreasing trend of 1.96mm/a and appearing cyclical variation period for 9 years and the secondary period for 24 years and 3 years.The spatial distribution of precipitation showed that the main change trend appeared that the average annual precipitation decreased warp-wise progressively from the southeast coast of Liaoning to the northwest inland,the flood areas converned along the plains of the middle and lower reaches of the big or medium-scale rivers' in the northern and middle parts of northwest in Liaoning province.