近1 000年长江中下游旱涝与气候变化关系

文章利用旱涝灾害历史记载与现代器测降水资料重建长江中下游旱涝灾害等级序列 ,并通过相关分析与波谱分析、交叉谱分析等分别探讨了长江中下游旱涝灾害发生与东太平洋海水表面温度 (SST)以及太阳活动 (太阳黑子数 )的关系。结果表明 ,长江中下游涝灾多发生于气候过渡期 ,即涝灾在气候由一种气候状态向另一种气候状态转变时期多发。谱分析与交叉谱分析结果表明 ,长江中下游旱涝灾害等级序列在 10～ 11年周期上与太阳黑子数存在相关 ,但两者有近 1年的滞后性。长江中下游旱涝灾害与SST的相关关系分析表明 ,SST正距平年份 ,往往对应着长江中下游的涝灾 ;而SST负距平年份往往对应着长江中下游旱灾。因而可以认为 ,SST与太阳活动变化(太阳黑子数量变化 )在不同周期频度上对长江中下游旱涝灾害具有明显影响。

THE RELATIONSHIP BETWEEN DROUGHTS,FLOODS AND CLIMATIC CHANGES IN THE MIDDLE AND LOWER REACHES OF THE CHANGJIANG RIVER SINCE LAST 1 000 YEARS

The history of floods and droughts in the middle reaches of the Changjiang River has been summarized. Possible links between floods and droughts, SST and separately sunspots activities were detected with the help of spectral and corre lation analysis. The research results indicate that the floods and droughts in the middle reaches of the Changjiang River were mainly occurred during the climatic transitional period when the climate changes from cold to warm or from warm to cold. Major fluctuations of the climate have played an important role for flooding in the middle reaches of the Changjiang River. The results of correlation analysis demonstrate that extreme events of floods and droughts were closely related to stronger solar activities. Both spectral and cross spectral analysis show that floods and droughts in the middle reaches of the Changjiang River is significantly relevant to sunspot activities with a chronological cycle of 10.2 years, 11 years and 11.5 years; and the time lag of 1 year is detected. There were weak correlation and SST changes between floods and droughts. Statistically the negative difference of SST is usually matched to droughts and the positive to flooding events in the middle reaches of the Changjiang River. Comparatively the solar activities created more significant impacts on the extreme drought and flood events if compared to the influences from SST changes in the middle reaches of the Changjiang River.