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干旱是制约黄淮海地区夏玉米产量稳定的主要农业气象灾害,明确粮食主产区农业干旱发生的演变规律,对于采取有效的防灾减灾对策意义重大。基于作物水分亏缺指数和夏玉米干旱等级指标,分析了黄淮海地区近40a夏玉米生长季干旱的时空变化规律。结果表明:夏玉米各生育阶段间比较,播种-出苗期水分亏缺指数和干旱发生概率最大。除播种-出苗期外,随着干旱等级的升高,干旱发生概率逐渐降低,但播种-出苗期则以特旱等级发生概率最大;各阶段水分亏缺指数无明显的时间变化趋势,但年际间波动较大,特别是夏玉米生长中后期,1997年是近40a干旱发生最为严重的年份,不仅干旱持续时间长,且发生范围也最大;水分亏缺指数空间分布范围在年代际间存在“缩小-增大-缩小”的变化规律,从各年代干旱等级及其分布范围看,1991-2000年干旱最严重,2001-2010年有所减轻。夏玉米各阶段水分亏缺指数及各等级干旱发生概率基本呈现为由东南向西北逐渐增大的变化趋势,河北大部、河南西部和北部以及山东的中西部地区是各阶段干旱概率的高值区。由于年际间的波动在增大,黄淮海地区夏玉米生长中后期极端干旱灾害发生的可能性较大,北部及西部地区更是干旱灾害的高发区,生产中仍需加强对干旱灾害的预测预报及防御工作。
Drought is the major agrometeorological disaster that restricts the summer maize yield in Huang-Huai-Hai region. To clarify the evolution of agricultural drought in the main grain-producing areas is of great significance for effective disaster prevention and mitigation measures. Based on the index of crop water deficit and summer maize drought index, the spatio-temporal variation of drought in summer maize growing season in Huang-Huai-Hai region was analyzed. The results showed that the moisture deficit index and the drought probability of sowing-seedling stage were the highest among the different growth stages of summer maize. With the exception of sowing-emergence stage, the probability of drought decreased gradually with the increase of drought level, but the probability of occurrence of drought was the highest at sowing-emergence stage. There was no obvious trend of time variation of water deficit index in each stage Especially during the middle and late summer of maize growth. 1997 was the most serious drought in recent 40 years. Not only did the drought last long but also occurred in the middle and late summer. The spatial distribution of water deficit index existed in the interdecadal From 1991 to 2000, the droughts were the most serious and the number of mitigation was reduced in 2001-2010. The water deficit index and the occurrence probability of drought at all stages of summer maize basically showed a trend of increasing gradually from southeast to northwest. The highest probability of drought in each stage was in most of Hebei, western and northern Henan and central and western Shandong Area. Due to the fluctuation in the interannual period, it is more likely that the extreme drought disaster will occur in the middle and late summer maize growing season in the Huang-Huai-Hai region, while the northern and western regions are more likely to be the high incidence areas of drought disasters. Prediction of drought disasters should be strengthened in production Forecast and defense work.