太阳活动与ENSO事件对云南省旱涝灾害的影响

根据云南省29个气象站点1958-2011年的逐月降水资料,运用Z指数法界定旱涝等级和年份,采用频次分析和Morlet小波技术分析了太阳活动与ENSO(厄尔尼诺和拉尼娜)事件对云南省旱涝灾害的影响。结果表明:(1) 近54 a云南省年均降水量总体呈下降趋势,下降速率为4.505 mm/10 a;旱涝灾害的发生呈增加趋势,进入21世纪之后旱灾发生频率明显高于涝灾发生频率。(2) 除了1967-1972年,20世纪60-90年代太阳黑子数和云南省旱涝指数呈明显的负相关关系。90年代中后期至今,二者则呈正相关关系。太阳黑子的减少趋势与研究区干旱化趋势相同。(3) ENSO事件与云南省旱涝灾害在14 a左右存在较好的周期对应关系;厄尔尼诺强度增大时研究区旱灾增多,拉尼娜强度增大时涝灾增多。

Influence of Solar Activities and ENSO Events on Drought and Flood in Yunnan Province

Based on the monthly meteorological data of 29 stations in Yunnan Province druing 1958-2011, after defining the level and years of droughts and floods by Z index, the influence of sunspot activity and ENSO(El-Nino-La-Nina) events on droughts and floods was analyzed by using frequency analysis and Morlet wavelet method. The results showed that:(1) In recent 54 years, the precipitation in Yunnan Province was decreasing with the speed of 4.505 mm/10 a, and the occurrence of drought and flood disasters was increased, and drought frequency was significantly higher than that of flood since the 21st Century.(2) The drought and flood disasters and the sunspot number were negatively correlated in 1960-1989 except 1967-1972, and turn to positively correlated after 1990; the sunspots decreasing trend was the same as drought trend.(3) There was a 14 years cycle corelation between ENSO events and drought and flood disasters in Yunnan Province. The drought disasters increased with the El-Nino intensity increase, and the flood disasters increased with the La-Nina intensity increase.