In a new paper published at Nature Scientific Reports, Renato Castelao and his former postdoc Hao Luo investigate the mechanisms driving upwelling jet separation along the US West Coast. The abrupt offshore displacement of the jet after separation is important because it dramatically widens the area influenced by the upwelling circulation, affecting nutrient distribution and increasing biological productivity. Many studies over the last 3 decades have suggested that interaction of the flow with a major cape off Oregon is the dominant process driving jet separation. In this study, Castelao and Luo demonstrate that flow-topography interaction is not a necessary condition for separation, and that the spatial structure of the wind field is the dominant factor controlling the offshore movement of the upwelling jet that occurs every summer. You can find out more about the research here.