关键词: 标准化降水蒸散指数(SPEI), 干湿变化, 干旱, 降水集中度(PCD), 降水集中期(PCP), 秦岭

Abstract: The values of SPEI(Standardized Precipitation Evapotranspiration Index),PCD(Precipitation-Concentration Degree),and PCP(Precipitation-Concentration Period)were calculated separately based on the metrological dataset derived from China Meteorological Data Sharing Service System.The dryness/wetness characters,precipitation heterogeneity and their relationship in the study area were analyzed using the Hurst Index,Mann-Kendall test and Morlet Wavelet analysis.The results are as follows: ① Climate in the study area was inclined to dryness in recent 55 years,and this trend was especially significant since 1995.Furthermore,the Hurst Index indicated that such dryness would persist for several years,and the persistence intensity in the north was stronger than that in the south of the Qinling Mountains.Spatially,the general climate was in a pattern of “moist in the south and dry in the north”;② The PCD in the study area was significantly increased,the spatial range of precipitation-concentration expanded from the west to the east during the period of 1960-2014,and the PCD in the south was higher than that in the north;③ There was a significant positive correlation between SPEI and PCD,and the correlation coefficient in the south was higher than that in the north of the Qinling Mountains.Whereas the correlation between SPEI and PCP was poor,and the correlation coefficient reached 0.3 only at 26% meteorological stations distributed mainly in the southeast;④ In the study areas,the higher the precipitation dispersion was,the more serious the drought would be.

Key words: SPEI, dryness/wetness variation, drought, PCD, PCP, the Qinling Mountains