EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Uncovering the Intrinsic Intensity-Size Relationship of Tropical Cyclones

Jie Sun1, Ming Cai1, Guosheng Liu1, Ruikai Yan, and Da-Lin Zhang2
Jie Sun et al.
  • 1Florida State University, Department of Earth, Ocean, and Atmospheric Science, United States of America
  • 2University of Maryland, Department of Atmospheric and Oceanic Science, United States of America

The central theme of this study is to explore if and how the intensity of a tropical cyclone (TC) is related to its size. This subject has puzzled atmospheric scientists since the work of Depperman (1947) but the existence of this relationship still remains elusive. The improved understanding of the intensity-size relationship of TCs will help coastal communities to prepare for the maximum potential damage as both the intensity and size have important impacts on wind damages, storm surges, and flooding. This study considers 33 years (1988–2020) of TC records of maximum surface winds and radii of maximum and gale-force winds over the North Atlantic Basin derived from the Extended Best Track Dataset. Analysis of these TC records reveals a robust positive correlation between loss of earth and relative angular momentum. This finding together with the inspiration from the seminal work of Emanuel and his collaborators leads us to combine absolute angular momentum and its frictional loss as a radially invariant quantity, referred to as “effective absolute angular momentum” (eAAM), for radial profiles of TC surface winds. It is demonstrated that the eAAM model can reproduce the observed complex intensity-size relationship of TCs, which can be further reduced to a quasi-linear one after factoring out the angular momentum loss and the radius of maximum surface winds. The findings of this study would not only advance our understanding of the complex TC intensity-size relation, but also allow for operational assessments of TC severity and potential damage just using its outer wind information.

How to cite: Sun, J., Cai, M., Liu, G., Yan, R., and Zhang, D.-L.: Uncovering the Intrinsic Intensity-Size Relationship of Tropical Cyclones, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-923,, 2023.