Tropical cyclogenesis:Controlling factors and physical mechanisms

In this review,advances in the understanding of the controlling factors and physical mechanisms of tropical cyclogenesis(TCG)are summarized from recent(2018–2022)research on TCG,as presented in the Tenth International Workshop on Tropical Cyclones(IWTC-10).Observational,theoretical,and numerical modeling studies published in recent years have advanced our knowledge on the influence of large-scale environmental factors on TCG.Furthermore,studies have shown clearly that appropriate convective coupling with tropical equatorial waves enhances the development chances of TCG.More recently,illuminating research has been carried out on analyzing the mechanisms by which oscillations and teleconnections(El Ni˜no Southern Oscillation(ENSO)in particular)modulate TCG globally,in association with changes in the sea surface temperature(SST).In addition to this,recent research has diligently addressed different aspects of TCG.Multiple studies have reported the applicability of unified theories and physical mechanisms of TCG in different ocean basins.Recently,research has been carried out on TCG under different flow pattern regimes,dry air intrusion,importance of marsupial pouch,genesis of Medicanes,wind shear,convection and vertical structure.Furthermore,studies have discussed the possibility of near equatorial TCG provided that there is enough supply of background vertical vorticity and relatively low vertical wind shear.Progress has been made to understand the role of climate change on global and regional TCG.However,there are still significant gaps which need to be addressed in order to better understand TCG prediction.

Recent advances in research on tropical cyclogenesis

This review article summarizes recent(2014-2019)advances in our understanding of tropical cyclogenesis,stemming from activities at the ninth International Workshop on Tropical Cyclones.Tropical cyclogenesis involves the interaction of dynamic and thermodynamic processes at multiple spatio-temporal scales.Studies have furthered our understanding of how tropical cyclogenesis may be affected by external processes,such as intraseasonal oscillations,monsoon circulations,the intertropical convergence zone,and midlatitude troughs and cutoff lows.Additionally,studies have furthered our understanding of how tropical cyclogenesis may be affected by internal processes,such as the organization of deep convection;the evolution of the"pouch"structure;the role of friction;the development of the moist,warm core;the importance of surface fluxes;and the role of the mid-level vortex.A relatively recent class of idealized,numerical simulations of tropical cyclogenesis in radiativeconvective equilibrium have highlighted the potential importance of radiative feedbacks on tropical cyclogenesis.We also offer some recommendations to the community on future directions for tropical cyclogenesis research.

Application of the rotating-convection paradigm for tropical cyclones to interpreting medicanes:An example

The rotating-convection paradigm for tropical cyclone behaviour is shown to provide an attractive and consistent framework for interpreting the dynamics of formation and intensification of at least some medicanes.The ideas are illustrated by a case study of the medicane that formed over the eastern Mediterranean in mid-December 2020.This case study is based on analyses of data from the European Centre for Medium Range Weather Forecasts(ECMWF),imagery from the European geostationary meteorological satellite,Meteosat Second Generation,and output from a convection permitting numerical simulation of the event using the United Kingdom(UK)Met Office regional model with the RAL2 physics configuration.Limitations of the currently widely accepted interpretation of medicanes in terms of the so-called Wind-Induced Surface Heat Exchange(WISHE)intensification mechanism are discussed.