Reexamining the Binary Interaction of Four Pairs of Tropical Cyclones in the Northwest Pacific

Abstract

Four pairs of tropical cyclones (TCs) in the vicinity of the Northwest (NW) Pacific have been restudied in this paper by decomposing a total flow into a climatic component and an anomaly as well as by a simple generalized beta-advection model (GBAM). These results contradict with previous reports that binary interactions occurred in the four pairs of TCs. The intensities of the TC pairs were not well matched to each other during their common lifetime period; thus, the result of GBAM revealed that the strong TC had a direct influence on the track of the weak TC, but the reverse was not true. All dynamical models for studying the binary interaction of two adjacent TCs depend on how to separate the TC vortex and surrounding flow from the total flow. In this paper, the anomalous component can be directly used to measure the intensities and sizes of TCs and other adjacent disturbances. The track of TC as an anomalous vortex is influenced by the climatic steering flow and interacts with other anomalous systems in the vicinity. Whether a binary interaction happens between two TCs and whether the two TCs interact with other anomalous systems can be determined by the GBAM at the optimal level near the maximum center of the vorticity anomaly.