京津冀地区干旱事件时空聚集性特征分析

在计算京津冀地区1961—2015年逐月标准化降水蒸散指数(SPEI)的基础上,借助SaTScan时空扫描软件,对不同程度干旱的时空聚集特征及其变化趋势进行了探究。结果表明:京津冀地区1961—2015年干旱发生频率持续增加,干旱化程度不断加剧；轻旱和中旱的时空聚集特征与总旱相似,集中发生于石家庄、保定、衡水和邢台；重旱和特旱的时空聚集特征相似,集中发生于廊坊、保定、沧州和石家庄；1961—1993年干旱聚集状态保持平稳,1994年后聚集的空间波动性增大,聚集范围和聚集程度均有所增强；随着干旱程度的加重,聚集发生的难度增加,聚集范围的差异性增大,空间波动性和不可预测性均有所增强。

Analysis on spatial-temporal gathering characteristics of drought events in Beijing-Tianjin-Hebei region

On the basis of calculating the monthly SPEI values of the Beijing-Tianjin-Hebei region from 1961 to 2015, the spatial-temporal gathering characteristics and change trends of different degrees of drought events were explored using the SaTScan spatial-temporal scanning software. The results showed that the frequency of drought in the Beijing-Tianjin-Hebei region continued to increase from 1961 to 2015, and the degree of drought continued to intensify. The spatial-temporal gathering characteristics of light drought and moderate drought are similar to that of total drought, and they mainly occur in Shijiazhuang, Baoding, Hengshui and Xingtai cities. The spatial-temporal gathering characteristics of severe drought and extreme drought are similar, and they occur mainly in Langfang, Baoding, Cangzhou and Shijiazhuang cities. From 1961 to 1993, the gathering state of drought remained stable. After 1994, the spatial fluctuation of drought gathering increased, and the gathering range and degree were enhanced. With the aggravation of drought, the difficulty of drought gathering occurrence increases, the difference of gathering range increases, and the spatial volatility and unpredictability are enhanced.