Figure 3
From: The air-sea interface and surface stress under tropical cyclones
A mechanism of rapid storm intensification and the bimodal distribution of lifetime maximum tropical cyclone intensity.
The shape of Ck/Cd dependence on wind speed containing a secondary maximum around 60 ms−1 (a) may be a factor in rapid intensification of some storms to major tropical cyclones and may explain the observed bimodal distribution of lifetime maximum intensity of tropical cyclones (b). Drag coefficient Cd is shown in Figure 2b; while, enthalpy coefficient Ck is interpolated from laboratory data8 for winds below 40 ms−1 and extended with a constant value Ck = 1.2 × 10−3 for winds above 40 ms−1, which is consistent with the available field data13. Continuous line in (b) is a 7th order polynomial fit to the global best-track tropical cyclone data38 on maximum intensity for 1982–2009 (dots).
