贵阳汛期旱涝演变特征及未来趋势预估

The Evolution Characteristic and Future Tendency Estimate of Guiyang Dryness and Wetness in Flood Season

首先对贵阳近500 a(1470—2008年)旱涝等级资料进行增补,利用该资料进行等级序列展开频次和多尺度分析。结果表明:近58 a,贵阳出现极端旱、偏旱的频次明显高于过去近500 a的平均状况;汛期出现偏旱和旱的次数明显增多,旱重于涝的趋势非常明显。从年代际和百年际尺度看,210 a周期是贵阳旱涝振荡的主周期,而50 a周期是次周期,且20世纪80年代的干旱程度高于历史上任何一个年代;从年际和年代际尺度上,24 a周期是贵阳旱涝振荡的主周期,而7 a周期是次周期;汛期降水偏少,一般与旱灾对应一致,但若降水偏多,对应汛期各月降水分布均匀,则不一定对应涝灾。最后,结合诊断结果,借助IPCC AR4最新的模式预估数据集,预估贵阳汛期降水在未来10 a左右将处于旱涝交替频发期,之后至21世纪40年代中期将处于少雨阶段,可能会出现较长时期的干旱。

Use the supplementation the data of the drought and flood grades for five hundred years in GuiYang,to make grades sequences frequency and multiple dimensioned analysis.The results showed that the frequencies of Guiyang appeared extreme drought and more drought in recent 58 years more than the mean value of recent 500 years.In flood season the frequencies of drought increased obviously and the drought more severe than flood.For the decadal and hundred decadal scales,210-year cycle is the main period of drought and flood oscillation and the 50-year cycle is the secondary.The 20 century and 80 years had the most server drought.For the inter-annual and decadal,24 years cycle is the main period of drought and flood oscillation and the 7 years cycle is the secondary.If the precipitation is less in the flood season,the drought may happen.But if the rainfall is more,the flood may not happen and the distribution of rainfall not even in each month.In the end combined the results of the model of IPCC AR4,in the future 10 years flood seasons,drought and flood will happen high frequency,and in the 40 years of the 21st century there are less precipitations and the drought will last long period.