Assessment of Regional Drought Trend and Risk over China: A Drought Climate Division Perspective
Assessment of Regional Drought Trend and Risk over China: A Drought Climate Division Perspective
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中国区域干旱趋势与风险评估：干旱气候划分视角
DOI：
10.1175/jcli-d-14-00403.1
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发表时间：
2015-09-01
影响因子：
4.9
通讯作者：
Chen, Yongqin David
中科院分区：
文献类型：
--
作者：
Li, Xiuzhen;Zhou, Wen;Chen, Yongqin David
将Ward聚类和k-均值聚类相结合应用于3个月标准化降水指数(SPI-03)，从气象和农业干旱的角度识别出中国全境的8个均匀干旱变化区段。中国东部(6个区)的经向梯度比中国西部(2个区)大。气候区划不仅有利于区域性干旱的评估，而且有利于大范围干旱的评估。趋势分析表明，近几十年来，中国北部西部偏湿，而中国东北偏北偏干。长江流域(YZ)在20世纪70年代末之后经历了更少、更弱的干旱。东北中国南部和中国-青藏高原西南部地区的长期旱情呈减少趋势，短期旱情不明显，长期旱情可能持续发展，从而使后续旱情发展更快、强度更大。对厄尔尼诺现象下干旱风险的审查表明，北部地区在发展阶段可能遭受干旱而不是洪水，在衰败阶段则相反。东南部的中国(SE)和YZ在成熟腐烂的春季更容易受到洪涝的影响，而东南部在腐烂的夏季更容易受到干旱的影响。这种独特的区域干旱风险格局与ENSO在不同阶段调制的异常水汽供应格局密切相关。
A combination of Ward's and k-means clustering was applied to a 3-month standardized precipitation index (SPI-03), and eight divisions of homogeneous drought variation throughout China were identified from the perspective of meteorological and agricultural droughts. A greater meridional gradient appeared over eastern China (six divisions) than over western China (two divisions).The climate division facilitated the evaluating of not only regional but also widespread droughts. Trend evaluation showed that western north China (WNC) has become increasingly wet in recent decades, while northern northeast China (NNE) has become increasingly dry. The Yangtze River valley (YZ) tended to experience less and weaker drought after the late 1970s. Southern northeast China (SNE) and the southwestern China-Tibetan Plateau (SW-TP) showed a decreasing trend in long-term but not short-term SPIs, implying that long-term drought conditions might develop continuously, thus allowing the following droughts to develop more rapidly and with a stronger intensity. Examination of the drought risk under El Nino revealed that northern regions were likely to suffer from drought rather than flood in the developing phase and the reverse in the decaying phase. Southeastern China (SE) and the YZ were vulnerable to flood rather than drought in the mature and decaying spring, with SE subjected to drought in the decaying summer. Such a distinctive regional pattern of drought risks was closely connected with the abnormal moisture supply patterns modulated by ENSO in different phases.