陕西省干旱变化特征及其对玉米产量的影响

Characteristics of drought change in Shaanxi Province and their influencce on corn yield

根据1961-2010年陕西省的逐日降水量资料,运用标准化降水指数(SPI)法、Morlet小波分析法,分析了干旱的时间变化特征、周期变化特征和空间变化特征。结合2007-2010年陕西省17县(区)的玉米产量资料,借助面板数据模型,就干旱对陕西省玉米单产的影响效应进行了研究。结果表明:陕西省干旱趋势逐渐增强,以20世纪90年代干旱最为严重;陕西省干旱的危害程度由北向南逐渐降低,陕北的危害最严重,关中次之,陕南最轻;同时,陕西省年干旱时间序列存在显著的准2~4a和准4 a尺度周期变化规律;另外,干旱与玉米产量呈显著的负相关,干旱指数(标准化降水指数)等级每增加一个级别,将导致陕西省每hm2耕地玉米产量减少128.985 kg。期望研究结果能为陕西省针对干旱气象灾害制定相应的减灾政策,有助于保障陕西地区玉米生产的稳定。

This paper used standardized precipitation index( SPI) and Morlet wavelet analysis method to analyze the temporal,periodic and spatial variation characteristics of drought in Shaanxi Province by the daily precipitation data from 1961 to 2010. Effect of drought on crop yield per unit area in 17 counties( districts) of Shaanxi Province was studied by the corn production data from 2007 to 2010 and the panel date model. The results showed that,the trend of drought is on the increase. The most serious case occurred in 1990 s. Damage degrees of drought in Shaanxi Province decreased continuously from north to south. The most serious condition occurred in northern Shaanxi,followed by Guanzhong. Southern Shaanxi is the lightest. Time series of drought years exhibits two significant periods. One is 2- 4 years and the other is 4 years. In addition,it is found that corn production is in negative correlation with the drought. One grade of increase of drought index( the standardized precipitation index) will lead to 128. 985 kg / hm2 reduction in corn production. It is hoped that the study may help to make relative disaster mitigation policies and to guarantee the stability of corn production in Shaanxi region.