近130年来赣江洪水灾害事件重建与特征诊断

Reconstruction on Flood Disaster in Ganjiang River and Characteristic Diagnosis for the Last 130 Years

利用赣江河漫滩相堆积剖面的415个样品,基于植物残体AMS-14C+137Cs/210Pb方法建立年代序列,利用粒度组份和粒度参数(包括平均粒径、粒度频数曲线和概率累积曲线等)指标,较高分辨率地辨识和重建了近130年来赣江流域的洪水灾害序列,并将其与太阳活动和ENSO事件进行了对比分析,结果表明:赣江近130年来洪水沉积物分层明显,沉积物的粒度组份特征和粒度参数特征在洪水期和平水期模式下差异明显,可以很好的指示洪水灾害事件,并识别出18次大小不同的洪水灾害事件。MK检验与累积距平分析结果表明,1954年和1977年附近发生过两次突变。1882-1911年和1943-1977年属于旱涝波动时期;而1911-1943年和1977-2014年则分别属于涝多于旱和旱多于涝的时期。小波分析表明,赣江流域旱涝变化以4年、16年、42年、74年为主要周期。交叉谱分析结果表明,赣江流域旱涝变化在11年尺度上与太阳黑子变化相关性明显,并且贯穿整个研究时段。2~8年尺度上赣江流域旱涝变化与ENSO事件相关性明显,可能与ENSO的2~7年周期有一定关系。

It is one of the important directions in the global change research that the reconstruction of time serial of paleoflood and the flood disaster events which can provide the basic data for regional drought forecast. In this research,fluvial floodplain deposition from GJ profile were processed to reconstruct the Ganjiang river flood event by ultra-high resolution recording for the last 130 years based on the time scale of AMS-^14 C ＋^137 Cs/^210 Pb and a number of size indicators and parameters such as average particle diameter,median diameter,sand and coarse silt components,cumulative frequency curve and probability curve. With the ultra-high resolution recording,we can compare the abnormal flooding in Ganjiang river region to the sunspot and ENSO. The results show： the sediments of the Ganjiang River from the past 130 years have been stratified obviously,the grain size characteristics of the sediments in non-flood season are different from those in the flood season. So,18 different sizes of flood disaster events had been identified. The results of MK test and cumulative anomaly analysis showed that there were two abrupt changes in 1954 and 1977; 1882-1911 and 1943-1977 are drought and flood fluctuations; 1911-1943 belong to flood more than drought and 1977-2014 belong to drought more than flood. Wavelet analysis shows that the period of drought and flood in Ganjiang river basin are 4 years,16 years,42 years and 74 years. The results of cross-spectrum analysis show that the period of drought and flood in Ganjiang river basin is related to the period of sunspot in11 year scale,and it runs through the whole research period. The correlation between drought and flood cycle and ENSO events in the Ganjiang river basin on the 2-8 year scale is likely to be related to the 2-7 year cycle of ENSO.