基于SPEI的陕西省干旱特征及其对玉米产量的影响

Analysis of Drought Characteristics and Its Effect on Maize Yield in Shaanxi Province Based on SPEI

基于陕西省1971-2020年32个气象站实测气象资料,计算不同尺度玉米生育期标准化降水蒸散指数(SPEI),利用旋转正交经验函数法、趋势分析法和小波分析法分析玉米不同生育期的干旱时空特征。结合陕西省9地区1990-2020年玉米单产数据,借助HP滤波法分离出玉米气象产量,采用交叉小波分析和线性回归法分析了干旱对玉米气象产量的影响。结果表明:①研究区干湿空间分布在玉米生育期可划分出关中、延安、榆林和陕南西南部4个干旱敏感区域;②在1971-2020年内,全生育期关中、榆林和延安地区呈干-湿交替变化,1990s末陕西大部分地区干旱较严重;③铜川、宝鸡、咸阳和渭南地区玉米气象产量与花丝期干湿状况密切相关,其余地区受全生育期干湿状况影响最大。玉米气象产量与干旱状况呈显著的正相关,且在1994-2000年存在1~4 a的共振周期;④榆林、铜川和渭南地区玉米气象产量随SPEI值增大而增加,而延安、宝鸡、咸阳、安康、汉中和商洛当SPEI值大于1.6或小于-0.4时会发生轻度及以上程度的减产。

Based on the measured meteorological data of 32 meteorological stations in Shaanxi province from 1971 to 2020,the spatial and temporal characteristics and periodic patterns of drought in different maize growth stages were analyzed by using the rotating orthogonal empirical function method,trend analysis method and wavelet analysis method on account of the standardized precipitation evapotranspiration index(SPEI).On the strength of the data of corn yield from 1990 to 2020 in 9 areas of Shaanxi Province,the meteorological yield of maize was separated by HP filtering method,and the effect of drought on meteorological yield of maize was analyzed by wavelet analysis and linear regression method.The results showed that:①dry characteristics in the study area could be divided into four drought-sensitive centers:Guanzhong,Yanan,Yulin and southwest Shaanxi,the trend of dryness was concentrated in Yanan,Guanzhong and Yulin regions.②During 1971-2020,Guanzhong,Yulin and Yanan showed dry-wet alternation during the whole growth period,and the drought was severe in most parts of Shaanxi Province in the late 1990s.③The meteorological yield of maize in Tongchuan,Baoji,Xianyang and Weinan regions was closely related to the dry and wet conditions at the silk stage,and the other regions were most affected by the dry and wet conditions at the whole growth stage.There was a significant positive correlation between maize meteorological yield and drought condition,and there was a resonance period of 1~4 a from 1994 to 2000.④The meteorological yield of maize in Yulin,Tongchuan and Weinan increased with the increase of SPEI value,while the yield of maize in Yanan,Baoji,Xianyang,Ankang,Hanzhong and Shangluo was slightly or more reduced when the SPEI value was greater than 1.6 or less than-0.4.