基于两种干旱指数对淮河流域干旱程度变化的分析

Analysis on the Change of Drought Degree in Huaihe River Basin Based on Two Drought Indexes

通过淮河1960~2012年间154个气象站的降水资料,选择标准化降水蒸散指数(SPEI)与标准化降水指数(SPI)作为干旱指标,对淮河流域的干旱特征变化进行分析。结果显示:(1) 时间尺度相同的情况下,干旱指数SPEI相对干旱指数SPI对干旱的评估偏低,整体评估偏湿。(2) 两个指数的时间序列图均表明淮河流域的干湿转变在逐渐平缓,且有干旱趋势,但SPEI表现更为平稳,波动较小。(3) 淮河流域整体属于洪旱灾害频发区,流域南部、东部、东北部是洪涝灾害频发区;流域中部、南部为干旱灾害频发区。(4) 淮河流域西部和北部面临较为严峻的干旱风险。对于Z值,SPEI普遍比SPI高,这表明在干旱趋势上,SPEI指数比SPI指数更倾向干旱趋势。Based on the precipitation data of 154 meteorological stations in Huaihe River from 1960 to 2012, the standardized precipitation evapotranspiration index (SPEI) and standardized precipitation index (SPI) are selected as drought indicators to analyze the changes of Drought Characteristics in Huaihe River Basin. The results show that: (1) Under the same time scale, the evaluation of drought-by-drought index SPEI is lower than that by drought index SPI, and the overall evaluation is wet. (2) The time series diagrams of the two indexes show that the dry wet transition in the Huaihe River Basin is gradually gentle, and there is a drought trend, but SPEI is more stable and has less fluctuation. (3) The Huaihe River Basin as a whole belongs to the area with frequent flood and drought disasters, and the south, East and northeast of the basin are the areas with frequent flood and waterlogging disasters;The central and southern parts of the basin are drought disaster prone areas. (4) The West and north of Huaihe River Basin are facing severe drought risk. For Z value, SPEI is generally higher than SPI, which indicates that SPEI index is more inclined to drought trend than SPI index.