基于降水Z指数的晋中市干旱特征分析

Analysis on Drought Characteristics of Jinzhong City Based on Precipitation Z Index

为了更好地了解晋中市干旱演变特征,为当地政府开展防灾减灾提供科学依据,利用晋中市所属11个县(区、市)1971~2020年逐月降水资料,采用降水Z指数作为气象干旱等级评价指标,分析了晋中市近五十年的年际及季节干旱变化特征.结果表明:近五十年来晋中市降水Z指数以0.023/10年微弱速度递增,其中1985~2008年期间为主要干旱时期;春季和秋季降水Z指数分别以0.148/10年和0.017/10年速率递增,夏季降水Z指数无明显变化,冬季降水Z指数以0.045/10年微弱的速率递减.晋中市严重干旱年发生的原因与夏季发生重旱和季节连旱有直接的关系.

To better understand the characteristics of drought evolution in Jinzhong City and improve the scientific basis for the local government to carry out disaster prevention and mitigation,the precipitation Z index was used as the drought indicator to analyze the annual and seasonal drought variation characteristics of Jinzhong City in recent 50 years,based on the monthly precipitation data of 11 counties(cities,districts)in Jinzhong City from 1971 to 2020.The results show that in the past 50 years,the precipitation Z index in Jinzhong City has increased at a weak rate of 0.023%/10 a,and the period from 1985 to 2008 was the main drought period;in the analysis of seasonal drought,the precipitation Z index in spring and autumn increased at the rate of 0.148%/10 a and 0.017%/10 a,respectively;there was no significant change in summer,and the Z index of precipitation in winter decreased at a weak rate of 0.045%/10 a.The causes of severe drought in Jinzhong City are directly related to the occurrence of severe drought in summer and seasonal drought.