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基于1880年以来全国洪灾灾情、耕地面积以及东部地区年降水量数据,采用EMD分解、MK趋势和突变检验与相关分析等方法,探讨19世纪末至21世纪初中国洪涝灾害的变化特征,及其与降水变化和人类活动之间的联系。结果表明:①19世纪末、20世纪50—60年代和20世纪末这3个时间段,是多世纪以来中国洪灾最剧烈的时期;其中19世纪末和20世纪50—60年代的洪灾剧烈期均对应降水丰沛期,而20世纪末的洪灾剧烈期降水并不十分丰沛。②中国洪灾存在多尺度特征,主要周期有2.7 a、5.2 a的年际变化、9.9 a的年代际和20.5 a、51.6 a的几十年际变化等;东部地区年降水量与洪灾变化周期对应关系较好。③从东部近50 a来年降水量变化来看,20世纪八九十年代洪灾上升并不是降水量增加的结果。降水强度增加、极值降水事件增多可能是其重要原因;另一方面则是由于水土流失加剧、湖泊围垦等人类活动因素的影响。此外,水利投资强度的变化对近50 a洪灾变化也有一定影响。
Based on the data of flood disaster, cultivated area and annual precipitation in eastern China since 1880, this paper explores the variation characteristics of floods in China from the late 19th century to the early 21st of the 21st century through EMD decomposition, MK trend, mutation test and correlation analysis, The link between changes in precipitation and human activity. The results show that: (1) The three flood periods of the late19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, the19th, Period, and the intense flood period of the flood in the late 20th century is not very abundant. ② There are multi-scale features of floods in China. The main periods are interannual variations of 2.7 a and 5.2 a, decadal variations of 9.9 a and 20.5 a, and densities of 51.6 a, respectively. The annual precipitation in eastern China is corresponding to the period of flood variation Good relationship. (3) Judging from the change of precipitation in the past 50 years in the eastern part of China, the flood rise in the 1980s and 1990s is not the result of the increase in precipitation. The increase of precipitation intensity and the increase of extreme precipitation events may be the important reasons for this; on the other hand, it is due to the influence of human activities such as intensified soil erosion and lake reclamation. In addition, the intensity of investment in water conservancy has also had some impact on flood changes in the past 50 years.