渭河关中段近400a来洪涝灾害变化研究

Scale and Temporal Properties of Flood Sequence of Guanzhong Reach of Weihe River During the Last 400 Years

通过历史文献资料的整理和统计分析的方法,对1600—1995年396a间渭河关中段洪涝灾害发生频次、等级和周期进行了研究。研究结果表明,渭河关中段在这一时段内共发生了99次洪涝灾害,平均约4a出现1次;其中轻度涝灾52次,中度涝灾35次,大涝灾8次,特大涝灾4次。根据洪涝灾害频次变化,可将这一时期洪涝灾害分为3个阶段,其中1600—1669年和1670—1859年属洪涝灾害少发阶段,但两阶段的变化趋势不一样,前者主要以灾害加剧为特征,后者则主要以灾害频次稳定为特征;1860—1995年是洪涝灾害多发阶段。周期分析发现准3a洪水周期最为明显,其次是7.14a的周期。初步判断准3a洪水周期可能与ENSO(赤道厄尔尼塔和南方涛动是一种海气耦合过程,统一称为ENSO)的2～7a周期存在一定联系。

Based on the method combining statistical analysis with the compilation of historical archives, this article makes an investigation of the temporal and scale properties of flood disasters that occurred in the Guanzhong reach of Weihe River during the last 400 years. According to the related historical archives, 99 flood events were recorded during the period, with an approximate frequency of 4 years. 52 of these floods are classified into small-scale flood, 35 into medium-scale flood, 8 into large flood, and 4 into catastrophic flood. Three main flood sub-periods are also distinguished. The period from 1600 to 1669 and the period from 1670 to 1859 were characterized by low-frequency floods, with a rising and a relatively level tendency, re- spectively, while the period from 1860 to 1995, by high frequency floods. Periodical analysis indicates that quasi 3-year is a most prominent cycle and 7.14-year, a secondary cycle, which are supposed to correspond to the 2-7 year cycle of ENSO.