Objective Identification of Tropical Cyclone Systems With Potential for Storm Surge Impact in the Western North Pacific

Abstract

The robust assessment of storm surge hazards induced by tropical cyclones in the Western North Pacific is constrained by only ca. 50 seasons of reliable observational data. This can be addressed by constructing physically consistent large tropical cyclone event sets, for example, from ensemble simulations. To allow efficient construction of these event sets, we propose a combination (M&S-WiTRACK) of two objective tracking methods relying solely on near-surface information and validate the performance of the combination on detecting tropical cyclones with potential for storm surge impact using ERA5. The M&S-WiTRACK is formed by a cyclone tracker (M&S) identifying tropical cyclone trajectories based on mean sea level pressure, with a wind-based storm impact identification algorithm (WiTRACK) determining potential storm surge impact areas using 10-m wind speed. For the first time, the general performance of the M&S for tracking tropical cyclones is evaluated and 84.9% of IBTrACS (with 18.3% false alarm rate) in the Western North Pacific from 1980 to 2019 are identified, which is well comparable to more data-intensive tropical cyclone trackers. Furthermore, M&S-WiTRACK successfully identifies over 85% of economic storm surge loss-related tropical cyclones in China. Nearly all tropical cyclones causing storm surges with economic losses exceeding 2 billion RMB are identified.