基于标准化降雨蒸散指数的水稻生育期干旱特征分析

Analysis of drought characteristics during growth period of rice based on standardized precipitation evaporation index

基于气候变化下南方干旱灾害发生频繁和影响不断加剧的事实,收集了典型水稻种植区高邮站点1951—2015年65 a逐月的降雨、气温数据资料,基于标准化降雨蒸散指数(standardi-zed precipitation evaporation index,SPEI)和Mann-Kendall(MK)趋势检验方法,研究和分析了水稻作物不同生育期内干旱发生频率、影响程度及其变化规律,结果表明:整个生育期内轻度干旱发生率最大,其中返青期和拔节抽穗期各为轻度干旱和重度干旱发生概率最大的生育期;从70年代至今干旱生育期次比呈上升趋势且集中在14%~28%波动,干旱生育期次数增多,干旱发生影响范围加大;在SPEI指数时间分布特征上,返青期、分蘖期和拔节抽穗期均呈现上升的趋势,乳熟期和黄熟期则均呈现下降的趋势,说明除乳熟期干旱程度呈现加强的趋势,返青期、分蘖期和拔节抽穗期干旱程度均呈现减小趋势;显著性分析表明,除拔节抽穗期为极显著性,乳熟期为显著性外,其余均呈不显著变化.研究成果可以有效地指导抗旱和灌溉,对水稻需水期尤其是关键需水期受旱影响评估提供参考,尽早做出灌溉决策,避免水稻作物受旱减产.

Based on the fact of frequent drought disaster and influence rising in south China with the climate changing,the precipitation and temperature data of month in Gaoyou weather station in the recent 65 years(from 1951 to 2015)were collected,using the standardized precipitation evaporation index(SPEI)and the method of Mann-Kendall(MK)trend test,to research and analyze the drought incidence,influence degree and change law in each growth stage of rice.The results show that the incidence of light drought is maximum in the whole growth stage,meanwhile the biggest probability of light drought is in turning green stage and that of heavy drought is in the jointing-earing stage.Since the 1970s,the times of drought growth stage have being on the rise and fluctuate between 14%and 28%.The number of drought growth periods increases,and the extent of drought increases.With the time distribution characteristics of SPEI,the turning green stage,tillering stage and jointing-earing stage have shown an upward trend,the milk stage and maturing stage have shown a downward trend,so it can be known that the drought degree at the milk stage shows a strengthening trend,that at the turning green stage,tillering stage and jointing-earing stage shows a decreasing trend.The trend detection shows that except that the jointing-earing stage has a very significance level and the milk stage has a significance level,the others are below the significance level.The results can effectively guide resisting drought and irrigation and provide reference to impact assessment of drought disaster in the key water requirement growth stage of rice,so as to make irrigation decision as early as possible and avoid the reduction of rice crop by drought.