基于SPEI的辽宁省玉米生育期干旱特征分析

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在全球气候变暖的背景下，探究玉米生育期的气候变化及干旱特征，对于预防干旱灾害对作物造成的损失，以及农业可持续发展意义重大。基于1967—2018年辽宁省33个国家级气象台站逐日观测数据，计算了不同月尺度下玉米各生育期标准降水蒸散指数（SPEI），并结合干旱频率及干旱站次比综合分析了干旱时空变化情况。结果表明：（1）辽宁省玉米生育期降水量以13.31 mm/10a的速率减少，与SPEI呈显著正相关（P<0.01）；气温以0.25℃/10a的速率显著上升（P<0.01），与SPEI呈负相关。（2）播种-出苗期、出苗-拔节期和喇叭口期SPEI在时间上均呈上升趋势，抽雄期和成熟期呈降低趋势；在空间上全生育期SPEI表现为西北向东南递增趋势。（3）全生育期干旱站次比以0.41%/10a的速率上升；出苗-拔节期干旱站次比呈减少趋势，其他生育阶段均呈上升趋势；发生干旱类型频次区域性干旱 > 部分区域性干旱 > 局域性干旱 > 全域性干旱。（4）全生育期干旱频率整体呈现出由西北向东南递减的特征，且干旱频发区主要在辽西地区；干旱发生频率轻旱 > 中旱 > 重旱 > 特旱。（5）出苗-拔节期为干旱站次比最高的时期；SPEI平均值和不同等级干旱频率最高的时期均为播种-出苗期。该研究成果可为区域农业干旱风险评价以及抗灾减灾等提供参考。;In the context of global warming, it is of great significance to explore the climate change and drought characteristics of maize growth period for preventing crop loss caused by drought disaster and agricultural sustainable development. Based on the daily observation data of 33 national meteorological stations in Liaoning Province from 1967 to 2018, this study calculated the standard precipitation evapotranspiration index (SPEI) at different growth stages of maize on monthly scales, and comprehensively analyzed the temporal and spatial variation of drought with the combination of drought frequency and drought station ratio. The results showed that:(1) the precipitation in the growth period of maize in Liaoning Province decreased by 13.31 mm/10a, which was significantly positively correlated with SPEI (P<0.01); temperature increased significantly at a rate of 0.25℃/10a (P<0.01), which was negatively correlated with SPEI. (2) In sowing-seedling stage, emergence-jointing stage and bell-mouth stage, SPEI all showed an upward trend, while in tasseling stage and maturation stage showed a downward trend. In terms of spatial variation, SPEI showed an increasing trend from northwest to southeast in the whole growth period. (3) During the whole growth period, the drought station ratio increased at a rate of 0.41%/10a. In the emergence-jointing stage, the ratio of drought stations decreased, while in other growth stages, it increased. The frequency of different drought types manifested as regional drought > partial regional drought > local drought > all regional drought. (4) The drought frequency of the whole growth period showed a characteristic of decreasing from northwest to southeast, and the drought-prone area was mainly in western Liaoning; and the drought frequency showed in order of light drought > medium drought > heavy drought > severe drought. (5) The emergence-jointing stage was the period with the highest drought station ratio; the highest average SPEI and the drought frequency of different grades were both in the sowing-seedling stage. The research results can provide reference for regional agricultural drought risk assessment and disaster mitigation.