2026/06/02 by Zirui Jiang, Xiaogang Huang, Jianfang Fei +2
Earth and Planetary Sciences · Environmental Science · #Tropical and Extratropical Cyclones Research #Climate variability and models #Meteorological Phenomena and Simulations
paper · doi:10.1175/mwr-d-25-0104.1
Abstract This study investigated the looping motion of global tropical cyclones (TCs). Using TC data from the International Best Track Archive for Climate Stewardship dataset, we objectively identified all looping events (LEs) from 1980 to 2023. Looping events occur in the basins where TCs are highly active, with 7.0% of all TCs having at least one loop. Cyclonic LEs accounted for 66.1% of all LEs, with this primarily occurring when TCs moved westward and equatorward before looping. The North Atlantic has the longest diameter and distance and the highest latitude among all basins. During looping, North Atlantic LEs exhibit the highest mean TC intensity and translation speed among all basins. Anticyclonic looping is associated with TC weakening. Finally, the method of obliquely rotated principal analysis in T mode was employed to investigate the background fields favoring the formation of maritime LEs. Based on the 500-hPa geopotential height field, we classified LEs in the Northern and Southern Hemispheres into four types. Furthermore, we analyzed the steering contributions of various weather systems within the composite mean fields of each type by piecewise potential vorticity inversion. The results indicated that LEs preferentially occurred when TCs were positioned between multiple weather systems that provide conflicting steering flows or were embedded within weak steering environments. Significance Statement Looping motion is one of the main challenges in track prediction. This study broadly investigated the spatiotemporal distribution and scale characteristics of global looping events, as well as the large-scale background conditions conducive to their occurrence. We found that looping motion exhibits different characteristics in different regions, and these unusual tracks preferentially occur between conflicting steering flows or weak steering environments. This study aimed to improve the skill of forecasting TC tracks and looping motions.