基于Z指数的江西省旱涝的指标与时空分布特征

Indexes and Temporal-Spatial Distribution Characteristics of Drought and Flood Based on Z-Index in Jiangxi Province

利用1961—2020年江西省逐日降水资料,基于Z指数分析确定了适用于江西省的旱涝指标。运用M-K检验、小波分析和EOF等方法分析了江西省旱涝时空分布特征。结果表明,1961—2020年江西省降水量年际变化大,20世纪90年代出现突变,但未出现显著的持续增加或减少。江西省干旱、雨涝事件存在准20 a主周期,从90年代开始偏涝年份明显增多,且雨涝呈增强的趋势。江西省旱涝主要存在4种空间分布型,分别为全区型、北涝(旱)南旱(涝)型、西涝(旱)东旱(涝)型、中心涝(旱)南北旱(涝)型,累计贡献率为83.61%。Z指数作为表征江西省旱涝指标的方法具有一定的适用性。

Based on the daily precipitation data in Jiangxi Province during 1961-2020,the drought and flood indexes in Jiangxi province were determined using the Z-index,the spatial and temporal distribution characteristics of drought and flood were discussed by using M-K test,wavelet analysis and EOF.The results showed that the inter-annual variation of precipitation in Jiangxi was great,with two abrupt changes in 1990s,but there was no significant continuous increase or decrease in precipitation.The occurrence of drought and flood events in Jiangxi Province presented obvious periodicity,with the main cycle of around 20 years.In general,the frequency and degree of drought and flood occurrence exhibited increasing trends.Moreover,since the 1990s,the drought and flood events were more frequent in Jiangxi Province.The spatial distribution of drought and flood in Jiangxi Province presented four types:whole region flood(drought),north flood(drought)-south drought(flood),west flood(drought)-east drought(flood),central flood(drought)-south and north drought(flood).The cumulative contribution rate was 83.61%.The Z-index showed certain applicability as a method to characterize the drought and flood of Jiangxi Province.