洪泽湖区气象旱涝演变特征
毕业论文关 键 词 ： 洪泽湖区，气象旱涝，标准化降水指数，旱涝周期，旱涝趋势
Abstract：This paper analyses the evolution of the drought and flooding in Hongze Lake from the view of the meteorological drought. Results show that: (1) With the expansion of the time scales, the negative correlation was found between SPI and the sensitivity of the precipitation, and the active correlation was found between SPI and the stability. (2) The frequency of the flood occurred in Hongze Lake is higher than that of the drought. However, the extent of the drought is generally higher than that of the flood. (3) The periods of the Morlet wavelet under different time scales are very different. The longer periods are more stable under long time scales. (4) Annual SPI has a stable period at about 6 years. SPI in spring exists a period at about 3 years expect 1966 to 1990. A period at about 6 years can be found between 1980 and 2000 in summer. Periods at about 2-4 years are obvious in autumn. Periods of winter SPI only exist in 1960s. (5) The precipitation of Hongze Lake is rising. Also the annual SPI and the probability of the flood tend to increase. (6) The winter SPI has a mutation and it will increase for a long time. And it is obvious for autumn to be drier. .
Keywords: Hongze Lake; meteorological drought; Standardized Precipitation Index; the periods of the drought and flooding; the tendencies of the drought and flooding
目录
1前言4
2研究区概况4
3数据和方法5
3.1数据5
3.2方法5
3.2.1标准化降水指数（SPI）5
3.2.2小波分析6
3.2.3Mann-Kendall检验7
4旱涝等级分析8
4.1SPI1分析8
4.2SPI3与水旱灾害的季节分析9
4.3SPI6分析.10
4.4SPI12与水旱灾害年分析10
5旱涝周期分析.10
6旱涝趋势及突变分析.12
6.1旱涝年变化趋势与突变.12
6.2旱涝的季节变化趋势及突变13
结论16
参考文献.17
致谢19
1 前言 国内学者们对于作为我国第四大淡水湖的洪泽湖，已给予充分的重视，在本领域，已经有学者对洪泽湖流域的降水情况[1]、水文特征[2]、洪涝灾害特性[3]、具体年限的旱涝天气[4-6]等做了不同程度的探讨。 由于人类的频繁活动和全球气候变暖的背景条件的影响，降水异常事件的频率和变化强度的区域性差异非常显著，预计到 2050 年，中国年平均降水将显著增加，降水的时空变率也较大[7]。其中，洪泽湖流域旱涝灾害愈加严重和频繁,尤其是在 1954、1991、2003年发生的特大洪涝灾害、2004 年洪泽湖流域出现的极端干旱使得洪泽湖流域的社会、经济发展蒙受巨大损失。而近 1,000a 来洪泽湖流域水旱灾害越来越频繁的趋势和该地区的气候变化也十分接近 [8]。因此,采用科学的方法获得洪泽湖区旱涝灾害的多年状况，分析变化周期和趋势对防范愈加脆弱的生态环境可能产生的风险具有重要的意义。 本文利用了洪泽湖区自 1957 年至2010 年的降水数据进行了分析和处理，以标准化降水指数SPI 为指标对于该时间段洪泽湖区的水旱情况进行了等级划分并对不同时间尺度的SPI 进行了比较分析；采取了小波分析的方法分析研究区水旱情况的周期；用 Mann-Kendall检验的方法分析研究区的水旱状况趋势；以统计图表的形式进行直观展示，使得洪泽湖区的水旱灾害情况显得清晰明了。