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基于1959-2008年中国南方地区249个气象台站的地面观测资料,以作物水分亏缺指数为玉米干旱指标,计算其干旱频率和干旱站次比,分析中国南方地区春玉米和夏玉米各生育阶段发生干旱的时空分布特征.结果表明:从干旱发生频率的空间分布看,春玉米在淮北、云南北部和华南南部发生的干旱较严重,在其他地区的干旱相对较轻;除了长江中下游地区、华南北部和西南东部的夏玉米在生育后期干旱较严重,研究区域内夏玉米在其生育前期和中期干旱较轻.从干旱面积和强度的变化趋势看,长江中下游地区春玉米在七叶到拔节阶段的干旱强度明显增加,在吐丝后到乳熟阶段的干旱面积和强度呈减小趋势;夏玉米在拔节后期到抽雄阶段以及吐丝后到乳熟阶段的干旱都呈减轻趋势.西南地区春玉米、夏玉米的干旱强度和范围没有明显趋势.从干旱面积和范围的年际和年代际变化看,长江中下游地区夏玉米的变化较大,而西南地区差异较小.
Based on the ground observation data of 249 meteorological stations in southern China from 1959 to 2008, the drought index and drought substation frequency were calculated using the crop water deficit index as the index of drought, and the distributions of spring maize and summer maize in southern China The results showed that: from the spatial distribution of drought frequency, spring maize suffered more serious drought in Huaibei, northern Yunnan and southern South China, while the drought in other areas was relatively lighter. In addition to the middle and lower reaches of the Yangtze River, Summer maize in the northern part of South China and eastern part of Southwest China had more severe drought in late growth stage, and the summer maize in the study area had less drought in its early and mid-term growth period. From the trend of drought area and intensity, The drought intensity at jointing stage increased significantly, and the area and intensity of drought in milky stage after silking tended to decrease. The drought of summer maize from late jointing stage to tasseling stage and after silking stage to milky stage were decreasing. There was no obvious trend in spring intensity and range of spring maize and summer maize in the region. From the interannual and interdecadal variations of arid area and range Look, the larger summer corn in the Yangtze River region, southwest regional differences small.