Results and Conclusions

The connection between the speed of the Manila galleon ships and the strength of the trade winds indicated to the researchers that slower voyages most likely represented an earlier onset of the monsoon season. The observed changes in voyage length suggest that profound changes in atmospheric circulation of the western Pacific took place during the seventeenth century, and that these changes were larger than anything experienced during the last 50 years.

"Hopefully this study, along with other research efforts taking place in China and in South America, will foster the international cooperation needed to fully explain these changes in tropical circulation," Diaz said. "With a better understanding of how circulation patterns have changed in the past, we'll be better equipped for forecasting and preparing for extreme weather patterns."