Does monsoon gyre always favour tropical cyclone rapid intensification?

Abstract

In this study, potential impacts of monsoon gyres (MG) on the development of a tropical cyclone (TC) are investigated using idealized numerical simulations. When a TC is embedded in an MG, our results show that its development is slower, and its intensity is weaker compared with that evolved with no background flow. We identified three MG dynamic mechanisms that can affect TC development. First, the superposition of TC and MG circulations produce a larger outer size for the TC. A TC with a larger size develops slowly and has a reduced capacity to organize convection through vorticity segregation process. Deep convection is located mainly outside the radius of maximum wind, resulting in slower intensification rates. Secondly, when the TC is embedded on the eastern flank of the MG, its outer profile becomes barotropically unstable. The asymmetric perturbations exhibit an up-shear tilting, which extracts kinetic energy from the primary vortex and thus hinders TC intensification. In the third mechanism, the vertical baroclinic nature of the MG imposes an ambient vertical wind shear on the TC, leading to a vertical tilting and increased asymmetric perturbation that hinders TC intensification. The MG relative humidity also impacts TC intensification, with negative impacts greater in drier environments. K E Y W O R D Sbarotropically unstable, baroclinic nature, dynamic mechanism, monsoon gyre, TC intensification 1 This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Simulated dynamics and thermodynamics processes leading to the rapid intensification of rare tropical cyclones over the North Indian Oceans

“…Geetha and Balachandran (2016) discussed the role of diabatic heating during RI of TC over NIO. Yan et al (2019) showed that monsoon gyre mechanisms aAect the RI of TCs. Zhang et al (2019) have shown that when mean kinetic energy is converted into eddy kinetic energy, an increase in the diabatic heating cause the RI of TCs.…”

On the intensification of typhoon Damrey with the monsoon gyre

“…It has been reported previously that monsoon gyres (MGs: Lander, 1994;1996;Harr et al, 1996) affect the track of TCs, which can experience sudden northward turning when they are embedded in an MG (Carr and Elsberry, 1995;Ge et al, 2018). Some studies suggested that MGs can modulate the intensity of TCs (Liang et al, 2016;2018a;2018b;Yan et al, 2019;Song et al, 2021). Based on a statistical analysis of the Joint Typhoon Warning Center (JTWC) dataset, Liang et al (2018a) and Song et al (2021) found that TCs are more likely to incur rapid weakening when they are embedded in an MG. Liang et al (2016;2018b) found that MGs affected the change in intensity of typhoon Chan-Hom (2015) by modulating the transport of mass and moisture into the TC.…”

“…Based on a statistical analysis of the Joint Typhoon Warning Center (JTWC) dataset, Liang et al (2018a) and Song et al (2021) found that TCs are more likely to incur rapid weakening when they are embedded in an MG. Liang et al (2016;2018b) found that MGs affected the change in intensity of typhoon Chan-Hom (2015) by modulating the transport of mass and moisture into the TC. Based on an idealized numerical experiment, Yan et al (2019) found that the development of TCs is slower when they are embedded in an MG and that MGs affect the intensity of TCs through vorticity segregation processes, barotropic instability and the modulation of vertical wind shear.…”

Rapid Weakening of Tropical Cyclones in Monsoon Gyres Over the Western North Pacific: A Revisit

“…They suggested that MG might weaken TC intensity by modulating TC's structure, which is consistent with their previous studies (Liang et al, 2016;Liang et al, 2018b). Based on idealized numerical experiments, Yan et al (2019) suggested that TC development in a MG could be interfered by three dynamical mechanisms, namely vorticity segregation process, barotropic instability, and VWS. Liang et al (2018a) and Wu et al (2013b) used a low-pass Lanczos filter with a 10-days cutoff to the wind fields in which the TC circulation was removed using the method of Kurihara et al (1993) and Kurihara et al (1995) to obtain a MG.…”