Sea-Breeze Interactions along a Concave Coastline in Southern Australia: Observations and Numerical Modeling Study

Abstract

Observations and numerical modeling of the bay and ocean breezes of Port Phillip Bay show that the interaction of these two breezes produces features undocumented in previous sea-breeze studies. The first of these is the formation of a mesoscale cyclonic eddy over the northern half of Port Phillip Bay. This eddy is due to enhanced convergence resulting-from the interaction of the bay and ocean breezes. The occurrence and position of this eddy is dependent on the strength and direction of the prevailing synoptic flow. The modeling studies show that the surrounding orography contributed to this enhanced convergence by channeling the low-level flow. It has also been found that at times the bay and ocean breeze coexist over the northern half of Port Phillip Bay. Under these conditions, the warmer, land-modified ocean breeze overlies the cool, shallow bay breeze. This is due to ground-based warming of the ocean breeze as it penetrates inland. The numerical results were in close agreement with the observations.