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

Has there been a recent shallowing of tropical cyclones?

Tsz-Kin Lai and Ralf Toumi
Tsz-Kin Lai and Ralf Toumi
  • Space and Atmospheric Physics Group, Department of Physics, Imperial College London, London, UK

Many aspects of tropical cyclone (TC) properties at the surface have been changing but any systematic vertical changes are unknown. Here we document a recent trend of high thick clouds of TCs. The global inner-core high thick cloud fraction measured by satellite has decreased from 2002 to 2021 by about 10% per decade. The TC inner-core surface rain rate is also found to have decreased during the same period by a similar percentage. This suppression of high thick clouds and rain has been largest during the intensification phase of the strongest TCs. Hence, these two independent and consistent observations suggest that the TC inner-core convection has weakened and that TCs have become shallower recently at least. For this period the lifetime maximum intensity of major TCs has not changed and this suggests an increased efficiency of the spin-up of TCs.

How to cite: Lai, T.-K. and Toumi, R.: Has there been a recent shallowing of tropical cyclones?, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8710,, 2023.