A substantial amount of recent work has shown that the maximum achievable intensity of tropical cyclones can be accurately estimated from the available thermodynamic energy, both initially in the atmosphere and that which becomes available as a result of the interaction between the cyclone and the underlying ocean.
However, whilst the thermodynamic estimates based on long - term mean conditions provided an excellent upper bound on the tropical cyclone intensity, it is also well known that most tropical cyclones do not reach this upper bound. This leads naturally to the question of what other processes limit the cyclone intensity in individual cases. Our investigations have identified a number of candidate processes. Perhaps the best known are the influence of strong vertical windshear, movement over land, and the effects of ocean cooling (especially for slowly moving tropical cyclones). We shall discuss in more detail the manner in which vertical wind shear can influence intensity. Other processes that will be addressed include: the non- linear relationship between the dynamical time-scale required for tropical cyclone intensification to proceed and the thermodynamic energy that is available; the influence of surrounding systems (many of which are at the mesoscale and difficult to resolve with the current observing systems); and the potential for vortex breakdown, in which the eye and radius of maximum winds region rapidly mix to a halt the intensification process. We also have evidence that the process of forming a tropical cyclone, especially in a monsoon environment, inherently leads to a a reduction in the thermodynamic capacity for tropical cyclone intensification.
These processes will be discussed using observations and a series of specially designed numerical experimentations