基于复杂网络的珠江流域片极端降水空间特征及时间规律分析

Analysis of the spatial characteristics and the temporal regime of extreme precipitation for the Pearl River basin: complex network perspective

  • 摘要: 研究极端降水特征和演变规律对流域防灾减灾具有重要意义。采用长期逐日高分辨率卫星降水数据, 结合统计显著性检验构建无向网络和有向网络, 分别编码极端降水的连接与传播, 以珠江流域片为例, 分析极端降水的空间特征与时间规律。结果表明: 西江流域有最大的极端降水发散源和汇聚地, 红水河、黔浔江、左江交界处度中心性大于0.5, 韩江流域和东江上游平均传播距离超过400 km, 根据最大5%聚类系数辨识出五大流域极端降水中心; 空间上, 存在韩江流域、东江流域、珠江三角洲中心, 长安-桂林场次中心来自柳江流域中心, 海南岛中心对珠江流域片有传入影响; 时间上, 极端降水主要在5月下旬至6月上旬从珠江流域片向韩江流域、东江流域和珠江三角洲中心传入, 在6月上中旬从韩江流域、东江流域、珠江三角洲和柳江流域中心向红水河、柳江、黔浔江及左江交界处传出。

     

    Abstract: Analysis of the characteristics and evolution of extreme precipitation is of great importance for basin disaster prevention and mitigation.Based on the long-term daily high-resolution satellite precipitation data, the undirected and directed complex network are constructed with the techniques of statistical significance tests, encoding the connection and propagation of extreme precipitation respectively.Taking the Pearl River basin as an example, the aim of this study is to investigate the spatial characteristics and temporal regime of extreme precipitation. The results show that the Xijiang River basin has the largest extreme precipitation divergence and convergence sources; degree centrality higher than 0.5 are observed in the junction of Hongshui River, Qianxun River and Zuojiang River basins; in the meantime, the Hanjiang River and Dongjiang River basins exhibit mean propagation distance larger than 400 km; the strongest 5% of the clustering coefficient identify the five major basin extreme precipitation centers. In terms of the spatial characteristics, the existence of the Hanjiang River Center, Dongjiang River Center, and Pearl River Delta Centers are verified, the Chang'an-Guilin Event Center is originated from the Liujiang River Center, and the Hainan Island Center is discovered to be an extreme precipitation influx source of the Pearl River basin. In terms of the temporal regime, from late May to early June extreme precipitation mainly propagates from the whole Pearl River basin to the Hanjiang River Center, Dongjiang River Center and Pearl River Delta Center, while from early to mid-June extreme precipitation mainly propagates from Hanjiang River Center, Dongjiang River Center, Pearl River Delta Center and Liujiang River Center to the junction of Hongshui River, Liujiang River, Qianxun River and Zuojiang River basins.

     

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