Evidence of Mesoscale Lows off the West Coast of New Zealand

Abstract

Mesoscale lows are observed off the central west coast, South Island, New Zealand. These features are evidenced in pressure dips measured at a buoy moored about 50 km off the west coast. They do not appear in measurements from coastal stations. Wind data at the buoy show complex variations sometimes consistent with the passage of cyclonic vortices in the flow. Further, wind data from satellite scatterometers often indicate high spatial variability near the buoy at the time of these pressure dips, and satellite imagery depicts cloud movements consistent with small-scale cyclonic circulations near the coast. These features are often observed in the cool air after the passage of a trough or front.