The Structural Differences Between Developing and Non-Developing Tropical Cyclone Seeds

doi:10.1029/2025JD044943

The Structural Differences Between Developing and Non-Developing Tropical Cyclone Seeds

2026-05-16

0

PRE

AI

DOI：10.1029/2025JD044943

Original

Original request for help

Save

Abstract

En 中文

We use a newly developed tropical cyclone (TC) seed tracking data set in ERA5 to investigate how the tangential wind structure of a seed differs between those that develop into TCs (“developing seeds”) and those that do not (“non-developing seeds”). Focusing on the concept of “structural compactness” (Cv) $\left({C}_{v}\right)$, a vortex structural parameter that characterizes the planetary Rossby wave drag on vortex intensity, we find that most developing seeds maintain relatively compact low-level dynamical structure throughout their lifetimes, whereas non-developing seeds exhibit a broader range of structures, with many being significantly incompact. This structural difference is reflected in the genesis probability of seeds: a seed with a lower Cv ${C}_{v}$ has a lower probability of developing into TC. Furthermore, for incompact seeds (Cv<1) $\left({C}_{v}< 1\right)$, the maximum time they persist in ERA5 tracks agrees well with a theoretical prediction that stronger planetary Rossby wave drag weakens such seeds more rapidly, limiting their persistence. This suggests that planetary Rossby wave drag will rapidly filter out incompact seeds within a few days after seed formation, and only seeds that are sufficiently compact would be expected to survive long enough to potentially undergo TC genesis. These findings highlight the importance of considering the seed's internal dynamical structure, rather than focusing solely on large-scale environmental conditions, when evaluating TC genesis potential. By incorporating seed compactness alongside traditional environmental parameters, we can gain a more comprehensive understanding of the seed-to-cyclone transition in different climates.

Keywords:

tropical cyclone

tropical cyclone genesis

tropical cyclone seed

rossby wave

rhines scale

The Structural Differences Between Developing and Non-Developing Tropical Cyclone Seeds

Abstract

Journal

Organization

Cited Papers