The Study Of Long-term Impacts Of Solar Activities On Meiyu In Changjiang-Huaihe River Region

The solar activities strongly affect the weather and climate on earth,which is closely related to human life and production.The Meiyu over Changjiang-Huaihe River region from June to July is an important part of summer rainfall in China. Abudance of deficiency of Meiyu directly has effect on disaster and its continuance of wet and drought in Changjiang-Huaihe River region. The area is one of the most developed regions in China, so the flood in the area have important impacts on the economic and social development in the eastern part of ChinaResearching the impact of solar cativities on Meiyu and its physical mechanisms, On the one hand it offers evidence of the influence of he solar activity on climate; On the other hand,it provides the ideas for forecast of Meiyu.This has important significance for disaster prevention and mitigation in summer,and it has important significance for economic and social development in china.Based on NGDC sunspots data, solar flare index data and China Meteorological Administration (CMA) daily precipitation data, onset and end date Provided by Jinagsu meteorologieal administration over the Changjiang-Huaihe region during the Meiyu period, the impact of solar activities on Meiyu in Changjiang-Huaihe River region are analyzed in terms of trend analysis, correlation analysis,composite analysis and so on. possible Physical processes about in fluences of the solar activity on Meiyu are also Analysed. The results show:(1) The variable rate of precipipitatiaon during theMeiyu period is Uneven distributed in space,and The variable rate of precipipitatiaon and intensity during the Meiyu period is basically the same distributed in space.The long-term trend of the onset date, the intensity of Meiyu has declined, The long-term trend of the end date, the length, the precipipitatiaon of Meiyu showed a rising trend.But The long-term trend of Meiyu characters is not obvious.The maximum trend coefficient of the precipitation of Meiyu is located in hangzhou area,while,there is little relationship between solar activities and Meiyu in hangzhou area.(2) Impact of solar activities on the precipitation and the intensity of Meiyu shows obviously Regional in Changjiang-Huaihe River region. Composite analysis between solar activity and precipitation anomaly percentage on the Meiyu are furtherly proved the solar activity on the influence of Meiyu. Composite analysis and correlation analysis results are basically the same In high solar activity years;while the results show large anomalies in low solar activity years.In low solar activity years,there maybe floods in Changjiang-Huaihe River region. Characterization of solar activity by sunspot number or the number of sunspot area are both in good agreement with the impact of the Meiyu, and are credible.(3)In a time scale of40a, solar flare to the effect of Meiyu is remarkable.The correlation analysis between Solar flare index and Meiyu are taked,the area which are significant at the0.05level are widely distributed.Impact of solar flare on the intensity of Meiyu is not significant, the area which are significant at the0.05level is not widely distributed.the distribution area of the positive and negative correlation coefficient between solar flare index, a year before the solar flare index and the precipitation, the intensity of Meiyu in the same period is very difference.The difference of the size distribution, regional distribution shows that the impact of medium-long term of the solar activity and space weather events on Meiyu is not consistent.(4) The medium-long term of the solar activity and space weather events impact the Meiyu,and their physical process have internal relations.the solar flare through many ways strongly impacts meiyu. Impact of Medium-long term solar activity on Meiyu should be the accumulation of impact of space weather events on Meiyu.