Analysis of the drought characteristics of Songnen Plain in the growing season in the past 109 years(1901- 2009)

The article is inclined to present our analysis of t drought characteristics of Songnen Plain in the growing season in t past 109 years(1901- 2009) due to the temporal and spati change,which helps us to make clear the drought-wet changing tre of the regional climate.Based on the data of the air temperature precipitation and other meteorological elements of Songnen Plain du ing 1901- 2009 from the time series of 3.1 climatic datasets in Cl matic Research Centerof the University of EastAnglia,we have do an analysis of the temporal-spatial distribution characteristics a changing cause of aridity index in the growing seasons via the Man Kendall test,climatic inclination rate and the spatial analysis met ods.The results of our analysis show:(1)The aridity index of t growing season has a degrading trend,indicating that the land surfa tends to be wetter and a spatial variation feature of gradual decrea from the west to the east during the past109 years.(2)The climat inclination rate of aridity index is- 0.019× 10- 1-0.004× 10-a- 1,and the aridity index in the western part of Songnen Pla proves to be less than- 0.005× 10- 1 a- 1 with 0.1 confident tes ing,suggesting that the declining trend is rather noticeable in th area.(3)The inter-decadal variation of the aridity indexismore ev dentwith the abrupt changes in the aridity index,which reveals t relative humid trend of the climatic in 1926.(4)Reviewing the si nificant change of the precipitation,the potential evapotranspiratio aswell as the aridity index in the growing season,it can be conclu ed that the changing tendency of the aridity indexismainly depende on the precipitation,which contributes to the increase of humid i dex.The results objectively reflects the character of drought-w change on the songnen Plains.