东北地区春玉米不同发育阶段热量指数时空特征

Spatiotemporal dynamics of heat index for spring maize at different developmental stages in Northeast China

根据中国东北三省82个气象站1961—2015年逐日平均气温和50个农业气象站1981—2013年春玉米发育期资料,研究了东北地区春玉米不同发育阶段热量指数的时空特征。结果表明:时间上,春玉米不同发育阶段的热量指数均表现为显著增加的趋势,增加速率最快的是三叶-拔节期,达0.20 a-1,最慢的是开花-乳熟期,为0.09 a-1;除出苗-三叶期外,各发育阶段均有半数以上的站点通过了0.1的显著性检验,其中三叶-拔节期和全生育期通过0.1显著性检验的站点高达95%以上。空间上,近55年中国东北春玉米热量指数在全生育期和不同发育阶段均表现出西南地区高、中部和北部地区低的空间分布格局,热量指数的变化速率则表现出北部较快、南部较慢的空间分布特征;随着年代际的推移,春玉米全生育期表现出热量指数较小的区域在逐渐缩小、热量指数较大的区域在逐渐扩大的时空分布特征。

The spatiotemporal dynamics of heat index of spring maize at different developmental stages of the whole growing season were examined using datasets including daily average air temperature during the past 55 years（ 1961-2015） at 82 meteorological stations and the phenophases of spring maize from 1981 to 2013 at 50 agro-meteorological stations. The results showed that the heat index of spring maize at different developmental stages exhibited significantly increasing trends. The rapidest increase of heat index occurred at the trefoil-elongation stage,reaching up to 0.20 a^-1. The slowest increase was at the flowering-milky ripening stage,with a value of 0.09 a^-1. The increasing trends of heat index in more than 50% meteorological stations passed the 0.1 significant test at all developmental stages except for the emergence-trefoil stage,and the percentages at both the trefoil-elongation stage and the whole growth period reached up to95%. The heat index of spring maize over the past 55 years displayed spatial distribution patterns,with higher values in the southwestern regions and lower values in the middle and northern regions for both whole growth period and different developmental stages. Moreover,the change rate of heat index for spring maize was faster in the northern regions than that in the southern regions. In terms of spatiotemporal dynamics,the area with smaller heat index during the whole growth period was gradually shrinking,whereas the area with larger heat index was gradually expanding over time.