Saturday, November 03, 2007

A hurricane network

Relationships of hurricanes affecting the United States can be examined using the methods of network analysis. Network analysis has been used in a variety of fields to examine relational data, but has yet to be used in the study of hurricane climatology. A single hurricane can affect more than one coastal region. This can happen when the regions are small relative to the hurricane size, when the hurricane comes onshore near regional boundaries, and when the hurricane makes multiple landfalls. Thus we suggest a network that links coastal locations (termed nodes) with particular hurricanes (termed links). The topology of the network can then be examined using local and global metrics. Certain regions of the coast (like Louisiana) may have high occurrence rates, but not high values of connectivity. Regions with the highest values of connectivity should include Florida and North Carolina. Virginia which has a relatively low occurrence rate is well-positioned in the network having a relatively high value of "betweenness". Conditional networks can be constructed based on below and above average values of important climate variables. Significant differences in the connectivity of the network are likely for different phases of ENSO.

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