标准化降水指数(SPI)和Z指数在淮北平原适用性研究

Study on the Applicability of Standardised Precipitation Index(SPI)and Z-index in Huaibei Plain

淮北平原是我国重要的粮食生产基地,分析其干旱时空变化特征和不同干旱指数的适用性,提高淮北平原抗旱风险能力,对农业生产和旱情监测具有重要意义。利用淮北平原20个气象站1962-2021年降水资料,计算了年尺度和季尺度的标准化降水指数(SPI)和Z指数,分析了两指数在淮北平原的一致性以及时空变化特征的差异性,并结合历史旱情资料对比分析,进一步研究两种干旱指数的适用性。结果表明,两指数在年、季尺度下的淮北平原均呈现较好一致性,并与该区降雨存在极强相关性;时间尺度上,两指数均在年以及夏冬两季呈缓慢湿润化趋势,春秋两季呈不显著干旱化趋势;空间尺度上,Z指数监测的干旱发生面积和发生频率均高于SPI指数;与历史旱情资料对比分析结果表明,与SPI指数相比Z指数监测结果具有一定持续性,不易出现异常现象,且与实际较为一致。综合分析表明,Z指数在淮北地区的干旱监测适用性较好。

The Huaibei Plain is an important grain production base in China.It is crucial to analyse the drought spatial and temporal variation characteristics and the applicability of different drought indices to improve the drought risk resistance of the Huaibei Plain,as well as to monitor agricultural production and drought conditions.This study utilized the precipitation data from 20 meteorological stations in the Huaibei Plain from 1962 to 2021.Standardized precipitation index(SPI)and Z-index at annual and seasonal scales were calculated,and consistency of the two indices as well as the variability of spatio-temporal change characteristics in the Huaibei Plain were analyzed.Furthermore, the applicability of the two drought indices was investigated by combining with comparative analyses of historical drought data.The results showed that the two indices showed good consistency in the Huaibei Plain at both annual and seasonal scales, and had strongcorrelation with the rainfall in the region;on the temporal scale, the two indices showed a slow wetting trend in the annual and summer/winterseasons, while a non-significant drying trend in the spring/autumn seasons;on the spatial scale, the drought-incidence area and thefrequency of droughts monitored by the Z-index were higher than that of the SPI-index;and the comparative analyses with historical droughtdata showed that the Z-index was more suitable than the SPI-index in the HuaiBei Plain. Comparison with historical drought data shows thatthe Z index has a certain degree of continuity compared with the SPI index, is not easy to appear anomalies, and is more consistent with theactual. Comprehensive analyses show that the Z index is suitable for drought monitoring in Huaibei.