Temporal and Spatial Variation of Extreme Precipitation in the Yellow River Basin from 1960 to 2012
Variation and trends in extreme climate events are receiving greater attention.Based on daily precipitation data recorded at 76 meteorological stations in the Yellow River Basin from 1960 to 2012,trends analysis,wavelet analysis,Mann-Kendall abrupt change analysis,and inverse distance weighting methods were employed to analyze the spatial distribution and temporal trends of extreme precipitation events.We found that in time,extreme precipitation,precipitation frequency and precipitation intensity displayed a decreasing trend at the rate of-0.64mrn/ 10a,-0.007 9d/10a and-0.078mm · d1/10a,respectively,while extreme precipitation ratio represented an increasing trend at a rate of 0.49%/10a.An abrupt change was not obvious for extreme precipitation,extreme precipitation frequency and extreme precipitation ratio,but extreme precipitation intensity did abruptly change in 1967.In addition,all extreme precipitation indices had two main oscillation cycles in common at 28a and 17a.A turning point of extreme precipitation occurred in 1982,2000 and 1974 in the upper,middle and lower basins of the Yellow River,respectively.There were many intersection points of the UF and UB curve line,but they were not mutations.In space,extreme precipitation increased from northwest to southeast across the Basin.Extreme precipitation frequency tended to increase gradually from north to the south; extreme precipitation and precipitation ratio increased gradually from west to east.Extreme precipitation in the western and northern Basin and surrounding areas of Xi'an showed an increasing trend; extreme precipitation frequency in western and northern regions of the Yellow River Basin also increased.An increasing trend of extreme precipitation intensity was mainly at Xining and Lanzhou,Yinchuan and surrounding areas of Xi'an.
extreme precipitation eventextreme precipitation indicesspatio-temporal variationYellow River Basin