This research was initiated while Duncan Cook was employed at the Defence Technology Agency (DTA) of the New Zealand Defence Force. Both authors wish to thank the DTA for its support of this work. The International Maritime Bureau provided access to its data on maritime piracy and kindly agreed to let us use the data in our research. We thank William Boos for contributing the Somali jet index data used in this paper. We are very grateful to Geoff Busswell and colleagues at the European Space Agency, who granted access to their GlobWave project (www.globwave.org) database of satellite altimeter observations. Finally, we wish to thank Ralph Marrett (DTA), Elaine Lindsay (ACU), and the anonymous reviewers of earlier versions of this paper for their thoughtful comments and insights.
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