Variance of Precipitation in Flood Season and Non-flood Season of Shangqiu during Recent 57 Years

By dint of linear regression,Mann-Kendall and other methods,the precipitation trend and mutation on annual precipitation,rainfall in flood season and non-flood season in Shangqiu from 1954 to 2010 were discussed.The result indicated that the trend of annual precipitation and rainfall in flood and non-flood seasons were not significant,annual precipitation increased by 6.74 mm/10 a,rainy season increased by 12.3 mm/10 a,and non-flood season decreased by 5.57 mm/10 a.This century annual and flood seasonal precipitation were the most in 1990s and the least in 1980s at the difference of 122.9 mm and 119.9 mm respectively.Non-flood seasonal precipitation was more in 1950s and 1970s,and less in 1980s,at a difference of 32.0 mm.The mutation of annual,flood and non-flood seasonal precipitation was not obvious.Mutations of annual and flood seasonal precipitation occurred in 2003,while non-flood seasonal precipitation occurred in 1970 and 2004.