1961-2019年东北地区作物生长不同阶段极端干期时空分布特征分析

Analysis of spatial and temporal variation characteristics of extreme dry spells for different crop growth stages in Northeast China from 1961 to 2019

基于1961-2019年东北地区87站逐日降水资料,分析了该区作物苗期、营养和生殖生长期、成熟期3个阶段极端干期长度的时空分布特征。结果表明,极端干期多年平均的空间分布反映了该区域的相对干湿状况,干旱、半干旱区干期较长,半湿润—湿润区干期较短,但非严格对应,与山脉地形、不同阶段降水异常区关系密切。近10-20年东北地区整体来看,苗期阶段干旱趋势有所缓解,干期缩短,而营养和生殖生长期、成熟期阶段则表现为变干的趋势。气候倾向率的空间分布显示整体和局部变化有所不同,苗期阶段全区大部分区域的春旱有所缓解,但局部区域的半湿润区仍存在变干趋势;营养和生殖生长期、成熟期阶段全区几乎一致的干期延长,尤其是东北南部的湿润区变干趋势比较突出。此外,各阶段极端干期开始日序近10年来均呈延后的趋势。

Based on the daily precipitation data of 87 stations in Northeast China from 1961 to 2019,the spatial-temporal characteristics of the period of extreme dry spell in stages of crop seedling,nutrition and reproductive growth,maturity were analyzed.The results show that multi-year average spatial distributions of the period of extreme dry spell reflect the relative dry-wet conditions in the region.The period is longer in arid and semi-arid areas and the period in humid/semi-humid area is shorter,but it does not strictly corresponded.It is closely related to mountain topography and abnormal precipitation areas of different stages.In the past 10 to 20 years in Northeast China,the drought trend in crop seedling stage has eased,and the period has been shortened,while the nutrition and reproductive growth,maturity stages have shown a drier tendency.The spatial distribution of climate tendency shows that the overall and partial changes are different.Spring drought in most areas of whole region at seedling stage has eased and dry tendency still appears in the semi-humid area of partial region.Nutrition and reproductive growth,maturity stages have almost the same period extension in the whole region,especially the humid regions in the southern part of the Northeast China have a prominent drying trend.In addition,the start sequence of the extreme dry spell in each stage has been delayed in the past 10 years.