标准化降水指数与有效干旱指数在新疆干旱监测中的应用

Application of standardized precipitation index and effective drought index in drought monitoring in Xinjiang

基于干旱监测理论,根据新疆测站1961—2010年逐日降水资料,对比分析了基于不同时间尺度(1、3、6、9、12、24个月)标准化降水指标(SPI)与有效干旱指数(EDI)对干旱监测的有效性与实用性。结果表明:不论针对短期干旱还是长期干旱,EDI监测能力均明显优于SPI。短时间尺度的SPI受短时间降水影响较大,能反映短时间新疆地区的干旱变化特征;随时间尺度的增加,SPI对短时间降水的响应能力较差,但仍可反映长时间序列下明显的干旱变化趋势。与SPI相比,EDI能够很好地反映出短期干旱和当时降水量的影响;同时能够随时间迁移,给每日降水量分配以不同权重,考虑前期降水量对当前干湿状况的影响。相关研究结果可为湿润区及其他气候区洪旱灾害监测提供重要理论依据。

Based on the drought monitoring theory and daily precipitation data covering the period of 1961-2010 in Xinjiang, we compared and analyzed the effectiveness and practicability of the effective drought index （EDI） and standardized precipitation indexes （SPI） based on different time scale （1-, 3-, 6-, 9-, 12-, 24-month）. The result shows that EDI is more superior to SPI no matter for short-term drought or long-term drought. SPI of short- term scale is greatly influenced by short duration precipitation, which obviously reflects the variation of drought and flood in short period in Xinjiang. With the expanding of time scale, SPI gradually loses its feedback from short duration precipitation, However, it can still reflect the obvious trend of drought and flood over the long-term scale. Like SPI, EDI can also reflect the influence caused by short-term drought and recent precipitation. Moreover, with the time passing by, EDI is able to give different weight to everyday precipitation considering the influence to the current drought statues caused by former precipitation. Relevant researches can provide significant theoretical basis to the drought monitoring in humid and some other climatic zones.