The results of numerical simulations of interaction and motion of binary tropical cyclones are presented. The numerical experiments are conducted using a multi-nested coupled tropical cyclone-ocean model. Two weak vortices are introduced into the model at different separation distances. After their intensification, storms begin interacting with each other. In previous study the interaction of binary storms has been studied in case of no background wind. Different regimes of storm interaction have been found. In the present study the interaction and motion of binary storms is studied when the storms are imbedded into a background flow. The flow is designed in such a way to reproduce trade winds with their eastern velocity component and the transition to westerlies northwards. The influence of the background flow on the interaction regimes found earlier is investigated. In different experiments storms are initially located in such a way that the background flow either favors their approach or the repulsion. The effects of capture of one of the interacting storm by the western flow on motion of both storms are studied. The numerical experiments are conducted with ocean coupling and without it. It is shown that the ocean coupling is of crucial importance for prediction of binary storm intensity and tracks. In some experiments the SST was initially homogeneous, so that only negative feedbacks related to the ocean cooling under storms were taken into account. In other experiments, the SST distribution was chosen in accordance with observations. A significant effect of the SST spatial inhomogeneity was observed. The tracks of binary storms observed in Atlantic during August 1995 were simulated. It was shown that accounting for the storm interaction drastically improved the track prediction.
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12th Conference on Atmospheric and Oceanic Fluid Dynamics