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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Network concepts to describe channel importance and change in multichannel systems: test results for the Jamuna River, Bangladesh
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Network concepts to describe channel importance and change in multichannel systems: test results for the Jamuna River, Bangladesh

机译：描述通道重要性和多通道系统变化的网络概念：孟加拉国Jamuna河的测试结果

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摘要

Most of the largest rivers on Earth have multiple active channels connected at bifurcations and confluences. At present a method to describe a channel network pattern and changes in the network beyond the simplistic braiding index is unavailable. Our objectives are to test a network approach to understand the character, stability and evolution of a multi-channel river pattern under natural discharge conditions. We developed a semi-automatic method to derive a chain-like directional network from images that represent the multi-channel river and to connect individual network elements through time. The Jamuna River was taken as an example with a series of Landsat TM and ETM+ images taken at irregular intervals between 1999 and 2004. We quantified the overall importance of individual channels in the entire network using a centrality property. Centrality showed that three reaches can be distinguished along the Jamuna with a different network character: the middle reach has dominantly one important channel, while upstream and downstream there are about two important channels. Temporally, relatively few channels changed dramatically in both low-flow and high-flow periods despite the increase of braiding index during a flood. Based on the centrality we calculated a weighted braiding index that represents the number of important channels in the network, which is about two in the Jamuna River and which is larger immediately after floods. We conclude that the network measure centrality provides a novel characterization of river channel networks, highlighting properties and tendencies that have morphological significance. Copyright ? 2013 John Wiley & Sons, Ltd.
机译：地球上大多数最大的河流都有多个分叉和汇合的活动通道。目前，除了简单的编织指标以外，还没有一种描述信道网络模式和网络变化的方法。我们的目标是测试一种网络方法，以了解自然流量条件下多渠道河流格局的特征，稳定性和演变。我们开发了一种半自动方法，从代表多渠道河流的图像中得出链状有向网络，并通过时间连接各个网络元素。以Jamuna河为例，以1999年至2004年之间以不规则间隔拍摄的一系列Landsat TM和ETM +图像为例。我们使用中心性来量化整个网络中各个渠道的总体重要性。中心性表明，可以在Jamuna沿岸区分三个河段，它们具有不同的网络特征：中游河段主要具有一个重要通道，而上游和下游大约有两个重要通道。暂时而言，尽管洪水期间的编织指数增加，但相对较少的通道在低流量和高流量期间都发生了显着变化。基于中心性，我们计算了一个加权编织指数，该指数代表了网络中重要河道的数量，在贾木纳河中约为2条，洪水发生后立即更大。我们得出的结论是，网络测度中心性提供了河道网络的新颖特征，突出了具有形态学意义的特性和趋势。版权？ 2013 John Wiley＆Sons，Ltd.

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