基于SPEI的甘肃省干旱特征分析

Analysis of Drought Characteristics Using SPEI in Gansu Province

干旱是一种复杂的自然现象,理解和掌握干旱事件的发生、发展状况对防治其危害具有重要意义。选用1982年—2015年间甘肃省25个地面气象观测站的月降水、温度数据,基于游程理论识别出干旱事件的历时和烈度,采用Copula函数对干旱特征变量进行联合,分析干旱特征变量的联合累计概率和干旱事件的联合重现期,结果表明:1982年—2015年间甘肃省出现的最低干旱事件频次为130次,最高150次,甘肃北部是主要的干旱灾害频发区,南部地区干旱发生频率相对较小;干旱历时和烈度的相关性较强,且随历时和烈度的不断增大,二者的联合累计概率和联合重现期也不断增大。研究可为旱作农业生态管理提供依据。

Drought is a complex natural phenomenon,and it is of great significance to understand and master the occurrence and development of drought events.Using meteorological data at 25 stations from 1982 to 2015 in Gansu province,SPEI was calculated.Based on the theory of run,drought duration and severity of drought events were recognized.Using Copula function connect drought duration and drought severity and analyzed the joint frequency and joint return.Results indicated that:from 1982 to 2015,the lowest frequency of drought events occurred in the northern Gansu was 130,with the highest frequency of 150 in southern Gansu.There is a strong correlation between drought duration and drought intensity.With the increase of drought duration and drought intensity,the combined cumulative probability and combined recurrence period of the two are also increasing.The research can provide basis for agricultural ecological management of dry farming.