In this section, summaries of recent progress in observations, forecasting, and research of tropical cyclone formation and extratropical transition are provided. Furthermore, requirements that remain for advancements in these topics are identified. During the period since IWTC-V, there have been improvements in observational capability, new research results into important physical processes, an...

[1] Theory suggests tropical cyclone maximum potential intensity increases with increasing ocean temperature. However, most tropical cyclones fail to achieve this maximum intensity. Instead, empirical studies suggest that tropical cyclone intensities are uniformly distributed between this maximum potential intensity and an intensity that marks the transition between tropical storm and hurricane...

Contributions of biologists to tropical cyclone research may improve by integrating concepts from other disciplines. Employing accumulated cyclone energy into protocols may foster greater integration of ecology and meteorology research. Considering experienced ecosystems as antifragile instead of just resilient may improve cross-referencing among ecological and social scientists. Quantifying ec...

The specific objectives of the current effort are: 1. To continue our study of the dynamical processes in tropical cyclones responsible for looping or erratic motion; 2. To continue the development of methods for (a) the introduction of synthetic tropical-cyclone-scale vortices in operational forecast models and (b) ensemble forecasting of tropical cyclones; 3. To continue a sensitivity study o...

This study investigates projected changes in the length of the tropical cyclone season due to greenhouse gas increases. Two sets of simulations are analyzed, both of which capture the relevant features of the observed annual cycle of tropical cyclones in the recent historical record. Both sets use output from the general circulation models (GCMs) of either phase 3 or phase 5 of the CMIP suite (...

The ventilation index serves as a theoretically based metric to assess possible changes in the statistics of tropical cyclones to combined changes in vertical wind shear, midlevel entropy deficit, and potential intensity in climate models. Model output from eight Coupled Model Intercomparison Project 5 models is used to calculate the ventilation index. The ventilation index and its relationship...

Understanding the processes that contribute to tropical cyclone (TC) formation, intensity and structure changes is essential for improving the predictability of TCs. Previous studies have focused mostly on the lowto mid-level processes leading to TC formation and rapid intensity and structure changes. The influence of upper-level atmospheric processes, especially the evolution of the outflow la...

The advance in targeted observations of tropical cyclone movement is reviewed in this article. The targeted observations from DOTSTAR (Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region) in understanding and improving the tropical cyclone track predictability is highlighted, along with the progress of the field program of THORPEX-PARC in the summer of 2008. The impact of...

Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are "quasi-p...

The large-scale equatorial circulation known as the Madden–Julian oscillation (MJO) has been shown to impact tropical cyclone activity in several basins around the globe. In this paper, the author utilizes an MJO index created by Wheeler and Hendon to examine its impacts on tropical genesis and intensification in the Atlantic. Large differences in frequency and intensity of tropical cyclone act...