基于EMD的洪涝灾害成灾面积波动的多时间尺度分析

应用经验模态分解（E如）方法分析了1950-2002年全国洪涝灾害成灾面积波动情况。结果表明：（1）洪涝灾害成灾面积存在准3年、准6年、准11年和准50年左右特征时间尺度的周期性波动；（2）各时间尺度的周期性振荡的贡献率中以准3年时间尺度的成灾面积振荡的贡献最大，说明洪涝灾害成灾面积波动以准3年时间尺度为主；（3）从各时间尺度的振荡来看，自70年代中期以来，洪涝灾害成灾面积的波动频率增加，从各时间尺度振荡的趋势看，洪涝灾害成灾面积仍处在增加阶段；而且近年来洪涝灾害成灾面积振荡的幅度增大，说明洪涝灾害强度加剧，频度增加。因此，应充分利用高科技手段对洪水进行实时跟踪、预报，尽可能减少其损失。

Analysis of Fluctuation of Inundated Area of Flood Disaster at Multi-time Scale Based on Empirical Mode Decomposition (EMD) Method in China

Empirical mode decomposition(EMD) method had been used to study the fluctuation of inundated area of flood disaster from 1950 to 2002 in China.The result showed that:(1)there were fluctuations of about 3-year,6-year,11-year and 50-year time scale.(2)By analyzing the contribution ratio of fluctuations at different time scale,contribution ratio of about 3-year period was the biggest,which meant about 3-year oscillation is the most prominent.(3)Shown from oscillation at different time-scale,the amplitude of the fluctuation of the inundated area had increased in recent years.In other words,the great flood disaster might come forth in some year.At the same time,from the trends of oscillation at different time-scale,the inundated area of flood disaster in China was still during the period of increasing.Due to the increase of frequency and the strength of intensity,the cause of the formation had been further analyzed and some countermeasures had been developed.