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›› 2016, Vol. 39 ›› Issue (1): 12-21.

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Characteristics and comparative analysis of reconstructed drought/flood grade sequence in the eastern Northwest China from 1470 to 1912

BI Shuo-ben, QIAN Yu-jun, CHEN Chang-chun, LI Xing-yu, XU Meng-ya   

  1. School of Geography and Remote Sensing, Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, China
  • Received:2015-07-17 Revised:2015-10-19 Online:2016-01-25

Abstract: In recent years,under the background of global climate anomalies,drought and flood disasters occurred frequently in China. The historical climate research is an important content of international Climate Variability and Predictability Program. In recent decades,some scientists had made great progress in reconstructing the sequences of drought and flood based on historical documentary files,however,most of these rebuild sequences of drought and flood were mainly concentrated in Eastern China. Due to lack of early data,there were few research and analysis of historical flood and drought in northwest China. Collecting and classifying the data of drought and flood disasters in the eastern Northwest China from 1470 to 1912,and according to the criterion of drought and flood grade,this paper reconstructed the sequence of drought and flood grade. The change characteristics of drought and flood disasters including the decade and century frequency,periodic and mutability,periodicity over the past 443 years in all the regions were analyzed by using the moving average,accumulative anomaly, moving t-test technique,and wavelet analysis. Finally,in order to test and verify the reliability of this sequence, regional long-term trend was analyzed by comparing the Huashan precipitation reconstructed sequences and D/F index in Longxi,and further compared drought and flood grade curve with the stable oxygen isotopic record both from typical provinces. Results showed that drought disasters took place frequently and seriously in the eastern Northwest China. The alternate phenomenon about drought and flood was obvious. Probability of drought and the partial drought were higher than flood disasters,and the probability of flood years was the lowest. The drought and flood disaster which had obvious phases features could be divided into four stages:1470-1540, 1541-1615,1616-1796 and 1797-1912. Based on the four stages,we could further divide them into twelve drought-partial or flood-partial periods. Using moving t-test technique,we found that there were 12 abrupt changes on decade scale and 5 abrupt changes on 50 years scale. The reconstructed sequences displayed a periodic variability in multiple scales,which were comparatively obvious on the timescale of 130-110 a,70-80 a,50-52 a and 28 a,10-15 a,5 a,especially on the timescale of 10-15 a and 28 a. The first four periodic oscillations,from high to low,were in 28 a,15 a,73 a and 5 a. According to the comparison analysis,reconstruction of drought and flood grade sequence has high consistency with other precipitation sequence,showing multiple similar trends that peaks and troughs appeared at the same time,and corresponds to stalagmites oxygen isotopes records during the same period. All these could be an indirect proof of reliability and feasibility of our recovered historical flood and drought grade sequence based on the historical document data. The results have important practical significance for the development of disaster prevention and mitigation measures in eastern Northwest China. The study will be very important to discover the changing rules of drought and flood disaster and make accurately forecast for the future climate.

Key words: eastern Northwest China, drought and flood grade sequence, mutation test, wavelet analysis, comparative analysis

CLC Number: 

  • P467