Characteristics and Possible Causes for Extreme Precipitation in Summer over the Loess Plateau

Using the daily precipitation datasets from 64 meteorological monitoring stations in the Loess Plateau and NCEP/NCAR reanalysis data during the period of 1961 -2016， the spatial-temporal variations of the extreme precipitation were investigated in the Loess Plateau.In addition， the similarities and differences in atmospheric circulation situation corresponding to strong and weak years of extreme precipitation， and in different ages were compared.Results showed that extreme precipitation was the major type in summer in the Loess Plateau， which accounted for about 70% of the total summer precipitation， and presented spatial decreases from east to west of the plateau.Under the background of overall decline of summer precipitation in the Loess Plateau from 1961 to 2016， the proportion of extreme precipitation showed an increasing trend among almost 70% of the stations.Comparison of atmospheric circulation between strong and weak year indicated that when Baikal low strengthened and the subtropical high extended no