The study found a strong correlation between successful pirate activity and both wind speed and wave height, as the figure shows. The study found that the onset of the summer monsoon had a pronounced impact on pirate activity, with pirate attacks all but ceasing during this period. This is due to the large increase in mean daily wind speed that accompanies the monsoon.
Sally Garrett, who co-authored the paper said: What we like about the GlobWave database is that it provides different data from a number of altimeters all in the same format with a very short turnaround time between collection and being available online. In the NZDF we have very small teams of people work on projects, so the ability to access an external database (rather than develop one is house), enables us to include data from a greater number of platforms and analyse a longer time series.
This study was presented in December 2011 at the International Congress of Biometeorology in Auckland, New Zealand and the full paper can be downloaded here.