近60年河北省冬小麦干旱风险时空规律 |
张力,陈阜,雷永登 |
Spatial and temporal patterns of drought risk for winter wheat grown in Hebei province in past 60 years |
Li ZHANG,Fu CHEN,Yong-Deng LEI |
图3 不同等级干旱频率随时间变化 |
Fig. 3 Different grades of drought frequency changed with time |
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