Climatic characteristics of the first soaking rain in spring sowing season of Liaoning province and its variation

Based on daily precipitation data of April and May from 1961 to 2007 in 14 weather stations in Liaoning province, the date of the first soaking rain, the seasonal distributions of soaking rainfall, the annual and inter-decadal variations and the relationships between the data of the first soaking rain, soaking rainfall and the precipitation during the sowing period were analyzed. The results indicate that the date of the first soaking rain in spring sowing period of Liaoning province appears lately and the soaking rainfall is more than the average since 1961, while their trends are not obvious. The date of the first soaking rain in spring sowing period of Liaoning province is of obvious inter-decadal characteristics. The correlation between the date and the soaking rainfall is positive, while it is not significant. The relationship between the date of the soaking rain and the precipitation during the sowing period is negative and significant. That is to say, the soaking rainfall is more or less and the precipitation during the sowing period is less or more in the year that the date of the soaking rain in spring sowing period occurs lately or early.