Main Influencing Factors of Climatic Aridity in the Most Serious Increasing Aridity Region of North Chi- na

摘要

Based on the data of monthly precipitation and other monthly meteorological elements of 661 meteorological stations over China from1961 to 2013,the temporal evolution characteristics of aridity in Hetao area of North China which is drying significantly were studied by using REOF,and the effects of summer monsoon and meteorological factors on the aridity index were discussed. The results showed that climatic aridity in Hetao area of North China tended to increase with time during 1961- 2013. The annual variation and overall trend of climatic aridity in Hetao area of North China was mainly influenced by ISASM1 before the 1990 s,and the degree of the influence weakened with global warming. There were certain differences between annual and decadal variations in the effects of the meteorological elements on climatic aridity. The impact of the thermal factors on aridity index was more significant than the dynamic factor after the 1990 s,revealing that climate warming aggravated climatic aridity in Hetao area of North China.