湖南省气候干湿特征及气象干旱指标的适用性

Analysis on Meteorological Arid-Wet Characteristics and Applicability of Meteorological Drought Indexes in Hunan Province

【目的】为揭示区域气候异常特征以及评估气象干旱指标的地区适用性,【方法】利用1960年-2015年湖南省87个气象站点逐月气候资料,计算得到PA(Precipitation Anomaly in Percentage)、相对湿润度指数(Relative Moisture Index,MI)、标准化降水指数(Standardized Precipitation Index,SPI)三种气象干旱指标,分析气候干湿特征,评估三种指标的地区适用性。【结果】近56年,湖南省PA、MI、SPI分别介于-30%~35%、-2.5%~100%、-1.85%~1.88%之间,对于雨涝特征,三种气象干旱指标均适合监测,其中,MI评价效果相对较好;对于干旱特征,适合用PA或SPI进行评价,MI不适合监测旱情。空间上,选取典型干旱年,SPI对湖南省各地干旱监测效果最好,其次是PA。季节尺度上,SPI显示湘南地区和湘西地区发生旱灾的概率较大,湘东地区相对较小。【结论】通过对比分析降水距平百分率、相对湿润度指数和标准化降水指数三种气象干旱指标对湖南省气候条件的适用性,表明SPI指标的地区适应性较强,旱涝监测效果相对较好。

【Objective】This study interprets climate anomalies and explores the applicability of me⁃teorological drought indexes in Hunan Province.【Method】Based on the meteorological data of 87 weath⁃er stations from 1960 to 2015 in the area,three indicators,namely,the Precipitation Anomaly in Percent⁃age(PA),the Relative Moisture Index(MI)and the Standardized Precipitation Index(SPI)were ob⁃tained to analyze the regional meteorological arid-wet characteristics and evaluate the applicability of these indexes.【Result】Over the last 56 years,the values ofPA,MI,andSPI range from-30%to 35%,-2.5%to 100%,-1.85 to 1.88,respectively.On the annual scale,three indicators are all suitable for theevaluation of waterlogging,but the evaluation effect of MI is better.For drought characteristics,it is suit⁃able to evaluate with PA or SPI,while MI is not suitable for the evaluation of drought characteristics in Hunan Province.Spatially,on the typical drought years selected,the research shows thatSPI has the best effect for drought monitoring,followed byPA,whileMI has the worst effect.Seasonally,SPI indicates that there is a high probability of drought in South Hunan and West Hunan,while there is a relatively low probability of drought in East Hunan.【Conclusion】By comparative analysis on meteorological arid-wet characteristics and the applicability of meteorological drought indexes(i.e.PA,MI,SPI)in Hunan Prov⁃ince,it shows thatSPI has a strong regional adaptability,and the monitoring effects on drought and flood are relatively good.