Research On Adaptability Of Five Drought Indices To The Huaihe River Basin

China is located in the East Asian, monsoon climate is significant, the inter-annual monsoon instability caused frequent drought in China. And The Huaihe River Basin is located in the north and south China climate transition zone, the southern and northern basin climate differences are significant, including the River Valley, and the southern summer in the northern edge of Meiyu, the inter-annual variation in rainfall, drought, floods and natural disasters. Therefore, a variety of meteorological drought indicators such as the CI index, precipitation anomaly percentage, standardized precipitation index, precipitation Z index, relative humidity index and other comparative studies, given their different times of the Huai River Basin in China’s drought monitoring and adapting the strengths and weaknesses nature (duration, mutation, etc.), and made particularly necessary to improve and perfect the method. Based on daily precipitation, average temperature, daily maximum temperature, daily minimum temperatures, sunshine hours, wind speed, relative humidity and other weather elements measured data of1960-2010about34surface weather observation stations in Huaihe River Basin, the Z-index, precipitation anomaly percentage, relative humidity index, standardized precipitation index, and CI index were calculated. Then gave these index a detailed comparison with the Recorded live data in the China Meteorological Disasters about Anhui volume, Henan volume, Shandong volume and Jiangsu volume.The results showed that:The Z index is the best in five kinds of drought index of34representative stations. In the spatial scale, The Z-index percentage of Anhui, Jiangsu, Henan and Shandong four provinces have reached more than70%, the best is the Shandong station, it reached75%; In addition, the better effect of the remaining four besides the CI is located in Shandong;In the scale of time, The coincidence rate of the Z index maintain at67%Only from April to June, all the rest are in70%above. The highest have reached78%in November;The SPI index and Z index are roughtly the same in effect but in January and February.The MI index is the worst, the best application of the best in Shandong is only49.6%, the coincidence rate of Pa index is poor from November to next February and fromJuly to August.The best effect application of the CI index is in Henan, on the contrary,the worst is in Shandong. The application effect of the CI index in Henan, Anhui two provinces are better than in Jiangsu and Shandong two coastal provinces, The application effect of the CI index is best in summer and its coincidence rate have reached80.3%, followed by the spring, its coincidence rate is74.2%, The effect of the CI index in autumn and winter is poorer, Their coincidence rate respectively is only58.1%and51.5%.In the whole of Huaihe Basin, only1290drought have reflected the actual situation events in2065drought events, the coincidence rate is62.5%.In the summer, the CI index effect is best, followed by the Z index and the SPI index.In Autumn, the Z index effect is best,followed by the SPI index and the Pa index. In Winter, the Z index effect is best, followed by the SPI index and the Pa index. The effect of the Pa and SPI index is good in SpringOf five kinds of drought index, the Z index is the best, but the statistics also found, the Z index previous threshold on Huaihe basin have partial width, and according to the cumulative frequency method, the Z index previous threshold were adjusted.Equal weight and non equal CI, MI index also be made a comparison, they have a very good consistency in the space distributing, but non weight index sensitivity to drought were higher. For the actual drought monitoring service, non weight index were significantly better than equal weight index.Finally, we gave some analysis to the drought spatial distribution characteristics of Huaihe basin and the area south based on the Z index. The first three feature vectors in the EOF vector field to Huaihe basin in winter, spring, summer and autumn four seasons reveal that Huaihe basin has three kinds of spatial distribution, In which the first feature vector is the only positive, indicating the region drought trend has good consistency. Through the REOF analysis, the precipitation anomaly spatial structure in the south is divided into5anomaly area that having higher correlation, these5abnormal area to the corresponding maximum load vector field are Yueyang station, Guangzhou station, Lishui station, Xinyang station, Chaohu station, respectively made a trend analysis, M-K mutation analysis and wavelet analysis.