The Influence of Solar Activity on Drought and Flood in Jingjinji Area
太阳活动对京津冀地区旱涝的影响

The relationships between drought index in the Jingjinji areas and relative sunspot number are analyzed by using the dryness and wetness grades series in last 500 years of China. There was prone to drought during the peaks solar activity and prone to flood during the troughs solar activity in the Jingjinji area. The wavelet analysis indicated that the relative sunspot number and drought index have quasi-period of 9.8 a, 78.6 a, 132.2 a, explained that the drought and flood in the jingjinji area and the sunspot activity has certain relations. The correlation moment analysis shows that correlation moment between drought index and relative sunspot number have staggered changes. The correlation coefficients are positive in 1479-1790 and 1856-1878, negative in 1791-1855 and 1960-2000. It is not significantly correlated in 1856-1878. The possible reasons for staggered changes of correlation coefficient were also analyzed in this paper.