1961—2020年中国北方向日葵种植区干湿变化特征及其成因分析
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Characteristics of dry and wet changes in sunflower growing areas in northern China and their causes from 1961 to 2020
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图5. 1961—2020年中国北方向日葵种植区生长季SPEI的M-K突变检验(a)及年代际尺度不同等级干旱出现频率(b) |
Fig.5. The M-K mutation test of SPEI during the growing period of sunflower in planting areas in northern China from 1961 to 2020 (a) and inter-decadal variation of occurrence frequency of drought with different levels (b) |
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