GEOGRAPHICAL RESEARCH ›› 2009, Vol. 28 ›› Issue (3): 592-600.doi: 10.11821/yj2009030004

• Earth Surface Processes • Previous Articles     Next Articles

The response of Holocene extreme floods in the Upper Changjiang River to changes of southwest monsoon

GE Zhao-shuai   

  1. School of Urban and Environmental Sciences, Xuzhou Normal University, Xuzhou 221116, China
  • Received:2008-06-15 Revised:2009-03-09 Online:2009-05-25 Published:2009-05-25
  • Supported by:

    高等学校博士点专项科研基金项目 (20060284028);徐州师范大学科研启动基金资助 (KY2005001)

Abstract: Exploring the relationship between extreme floods in the Upper Changjiang River (UCR) and the southwest (SW) monsoon is of important theoretical and practical significance by means of the floods peak discharge. The climatic background of the extreme floods in the UCR was analyzed in this paper by recurring to 24 extreme Holocene floods and flood disaster data during the last 2000 years in Sichuan-Chongqing area. Summer SW monsoon is the main sources of precipitation in UCR. The flood caused by violent storm is the major flood type in UCR. The extreme floods in the UCR are related to the abnormal enhancement of SW monsoon. The analogism was employed for exploring the response of extreme floods to the Holocene climate change. The Holocene climate change information recorded in North Atlantic Ocean drilling core, Dongge stalagmite, Arabian sea drilling core and other proxies were used for analyzing the subjects. Based on the analysis of the relationship between the series of extreme floods in the UCR and the SW monsoon change during Holocene recorded by the marine core in the Arabian Sea, the extreme floods were greatly consistent with the SW monsoon change. The extreme floods event period during Holocene, characterized by the rapid climate change, were mostly the stage of strong climatic fluctuation or the climatic transition period. In comparison of the extreme floods to the climate change recorded in the North Atlantic Ocean, all the extreme flood periods are not consistent with the rapid climate change, which is similar to the scenario of the stalagmite in Dongge Cave in Guizhou Province. It is indicated that the flood event affected by the hydrologic-meteorologic process tended to be a local event. Compared with the flood disasters recorded in historical documents, the extreme floods with greater peak discharge and low frequency responded to the climate change very well, whereas the floods with small peak discharge and low frequency were more random. There were great differences in magnitude of historical floods recorded in documents. Therefore we should do analyses to distinguish these events based on the data rather than mix them up. The latter may cover up the true mechanism of the extreme floods and their responses to the climate change.

Key words: extreme floods, southwest monsoon, Holocene, the Upper Changjiang River