Analysis of Precipitation Change in Henan Province over the Past 49 Years

The annual and seasonal precipitation,annual average amount of precipitation days and extreme precipitation events in Henan Province were observed via methods of trend analysis,5-year sliding analysis and t-test based on the data provided by National Meteorological Information Center of daily precipitation data which at 17 meteorological stations in Henan from 1961 to 2009.The results show that the annual precipitation and precipitation days have decreased in the past 49 years,and annual amplitude is bigger.Precipitation and precipitation days show declining trends in springs and autumns,while increasing trends in summers and winters.Extreme precipitation events have increased during the study years.In the space,the trend of the rainfall and extreme precipitation events are upwards in the east and downwards in the west in the research area.Precipitation days mainly show a decreasing tendency in whole area.