Dynamic mechanism for the evolution and rapid intensification of Typhoon Hato (2017)

Abstract

This study investigated the evolution of Typhoon Hato (1713) and analyzed the inner dynamics of its rapid intensification. The moving path of Hato was controlled by the southwestern part of the western Pacific subtropical high which extended westward significantly. Due to a relatively steady leading steering flow, the trajectory of Hato showed a straight ESE to WNW direction, leading to disastrous rainfall in southern Guangdong Province on 23 August before and after the landfall of the typhoon. In addition, Typhoon Hato exhibited a rapid intensification period from 3 to 13 o'clock on 23 August, with central wind speeds increasing from 35 to 48 m/s. This study mainly examined the inner dynamics of the development of Hato, especially its rapid intensification period. The regression analysis results showed that Hato was generated and developed under a TD‐type‐like wave. The coupled convection and vortex provided a favorable environment for the development of Hato. The analysis of the barotropic eddy kinetic energy (EKE) and latent heat flux further demonstrated this scenario. The results showed that the regions with a positive EKE tendency and strong latent heat release were consistent with the reach of and shifted westward with Hato. The EKE conversion was enhanced significantly on 23 August, with a maximum intensity observed over the northern South China Sea and southern Guangdong Province. The mean kinetic energy was largely converted to EKE, which, together with the great latent heat release, led to the rapid intensification of Hato.

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

“…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. Our companion paper, Munsi 2021), showed that high-resolution mesoscale analysis for these TCs simulated the RI appropriately.…”

Importance of Air-Sea Coupling in Simulating Tropical Cyclone Intensity at Landfall

“…Several studies have examined its physical mechanism. Zhang et al (2019) identified the presence of barotropic eddy kinetic energy and large latent heat flux near the coastal region. The substantial amount of latent heat release during the passage of Hato (2017) was further analyzed by Pun et al (2019), who reported that the continental shelf extending from South China, which is about 200 km away from the coast and less than 200 m depth, can account for the well-mixed warm water and thus the intensification of Typhoon Hato (2017).…”

Increased severe landfall typhoons in China since 2004

“…Typhoon destructive potential has decreased by 35% over the western North Pacific during the recent decade (Lin and Chan, 2015). However, severe damages to public facilities, tremendous economic losses and huge casualties caused by landfall typhoons occur as usual (Lin et al ., 2014; Zhang et al ., 2019a). It is well‐known that landfall typhoons are more dangerous than those stay offshore, especially for severe typhoons.…”

“…Recently, Zhang et al . (2019a); Zhang et al ., 2019b) found the genesis locations of landfall typhoons in southern China experienced an interdecadal northwestward shift since 1998, with only a slightly increasing trend.…”

“…The differences in the trend of severe landfall typhoons (SLTYs) may be partly attributed to the TC data sets without observed maximum sustained wind speeds when they made landfall in China before 1973 and the inhomogeneity occurred around 1972 (Ying et al, 2014). Recently, Zhang et al (2019a); Zhang et al, 2019b) found the genesis locations of landfall typhoons in southern China experienced an interdecadal northwestward shift since 1998, with only a slightly increasing trend.…”