Quantifying Spatial Drought Propagation Potential in North America Using Complex Network Theory
Quantifying Spatial Drought Propagation Potential in North America Using Complex Network Theory
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DOI：
10.1029/2021wr030914
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发表时间：
2022-03-01
影响因子：
5.4
通讯作者：
Mishra, Ashok
中科院分区：
文献类型：
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作者：
Konapala, Goutam;Mondal, Somnath;Mishra, Ashok
干旱具有占主导地位的三维(3-D)时空结构，通常跨度达数百公里，通常持续数月至数年。在这里，我们介绍了一个新的框架，以探索基于网络理论概念的干旱演变的三维结构。该框架被应用于利用标准化降水蒸发指数(SPEI)确定北美大陆1901-2014年间大范围干旱的关键来源区域。我们建立了一个空间网络，连接北美大陆的干旱开始时间。使用空间加权网络划分算法，然后将整个大陆分类为区域空间干旱网络(RSN)，其中干旱更有可能在这些区域系统内传播。最后，应用定制的网络度量来识别干旱起始点进一步传播到区域空间网络内其他区域的位置(源区域)。我们的结果表明，西海岸、德克萨斯沿海地区和阿肯色州东南部是大气干旱传播到北美西部、中南部和东部的主要源区。旱源区的形成是由于高压脊和异常风型的存在。此外，我们的结果表明，来自这些源区的干旱传播可能是由于水分输送不足所致。拟议的框架可以帮助开发干旱和其他空间上广泛的极端事件(如热浪和洪水)的预警检测系统。
Droughts have a dominant three-dimensional (3-D) spatiotemporal structure typically spanning hundreds of kilometers and often lasting for months to years. Here, we introduced a novel framework to explore the 3-D structure of the evolution of droughts based on network theory concepts. The proposed framework is applied to identify critical source regions responsible for large-scale drought onsets during 1901-2014 for the North American continent using the Standardized Precipitation Evaporation Index (SPEI). We built a spatial network connecting the drought onset timings for the North American continent. Using a spatially weighted network partitioning algorithm, the whole continent is then classified into regional spatial drought networks (RSN), where droughts are more likely to propagate within these regional systems. Finally, a customized network metric was applied to identify locations (source regions) where the drought onsets further propagate to other areas within the regional spatial network. Our results indicated that the West coast, Texas coastal region, and Southeastern Arkansas as major source regions through which atmospheric drought propagates to Western, South Central, and Eastern North America. The formation of drought source regions are due to presence of high pressure ridges and anomalous wind patterns. Furthermore, our results indicate that the drought propagation from these source regions may be due to inadequate moisture transport. The proposed framework can help to develop an early warning detection system for droughts and other spatially extensive extreme events such as heatwaves and floods.