Analysis of Drought Change Characteristics in Hebei Province from 1981 to 2020 Based on SPEI
Based on monthly precipitation and temperature data of 138 meteorological stations in Hebei Province from 1981 to 2020,the standardized precipitation evapotranspiration index(SPEI)for different time scales was calculated,and Sen trend analysis,Mann-Kendall test and inverse distance weight interpolation methods were used to analyze the spatiotemporal variation characteristics of drought in Hebei Province in the past 40 years.The results show that the monthly,quarterly and annual SPEI values in Hebei Province show a downward trend from 1981 to 2020.With the increase of the time scale,the frequency of drought decreases and the duration increases.Spring,summer and interannual SPEI values show a downward trend,The SPEI values in autumn and winter show an upward trend.The spring and winter during 2016～2020 and 2011～2020 are in a humid state,and the summer and autumn are in a dry state.From 2011 to 2020,most areas are in a state of drought.The drought frequency of different seasons and years shows an overall increasing trend.There were more mild and moderate drought events than severe drought events in Hebei Province.The proportion of regions with reduced SPEI values in the 1990s and 2010s is large,and the proportion of regions with increased SPEI values in the 1980s and 2000s is large.
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