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近62 a湖北省旱涝特征分析

Analysis of drought and flood characteristics in Hubei Province in recent 62 years

  • 摘要: 利用湖北省76个国家气象站1961—2022年地面气象观测资料,基于气象干旱综合监测指数(Meteorological Drought Composite Index,MCI)和有效降水指数(Effective Precipitation,EP)识别湖北省历年干旱和洪涝过程,分析近62 a旱涝过程频次时空变化和旱涝年、旱涝转换特征以及2010年以来旱涝特点。结果表明:湖北省旱涝频发区总体呈东涝西旱、南涝北旱的片状分布。干旱和暴雨洪涝发生频次分别呈现波动式下降、上升趋势。干旱主要发生在春季和伏秋季,发生频次总体呈减少趋势,但夏秋干旱以及极端干旱有趋多增强的态势;暴雨洪涝主要集中在夏季,发生频次呈增多趋势。旱涝年年际间呈现连旱2~4 a、连涝2~3 a或旱涝交替的特征,部分年份年内旱涝并存、旱涝急转,2010年以来无旱涝并存年。旱涝转换站数年际间波动较大,呈现5个阶段性上升特征,各递增阶段最大站数呈递减趋势。2010年以来旱涝呈现极端性增强、骤发性增多及连旱连涝的特点。

     

    Abstract: Using the surface meteorological observation data of 76 national meteorological stations in Hubei Province from 1961 to 2022, the drought and flood processes based on the meteorological drought composite index (MCI) and effective precipitation index (EP) are first identified. Then we analyze the spatial-temporal distribution of the frequency of the drought-flood processes, the characteristics of the drought-flood year, the drought-flood transitions over the past 62 years, and the characteristics of drought and flood processes since 2010. The results show that the frequent occurrence area of droughts and floods in Hubei Province is generally characterized by the flaky distribution with floods in the east and droughts in the west, while floods in the south and droughts in the north. The occurrence frequency of droughts and rainstorm floods shows a fluctuating decreasing and increasing trend, respectively. The droughts mainly occur in spring and summer-autumn with a decreasing trend in frequency, but an increasing trend is found in the summer-autumn droughts and extreme droughts. Comparatively, the rainstorms mainly concentrate in summer and show an increasing trend in frequency. The annual variation of drought-flood year is characterized by continuous droughts for 2-4 years, continuous floods for 2-3 years, or alternation of droughts and floods. In some years, droughts and floods coexist in the same year, while abrupt drought-flood transitions are also found. However, there has been no drought-flood coexistence in the same year since 2010. The annual variation of the number of stations with drought-flood transition fluctuates greatly, showing a five-stage increasing characteristic with the maximum value of each stage decreasing. Since 2010, the drought and flood events show characteristics of extreme enhancement, sudden increases, and successive droughts and floods.

     

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