Interdecadal Changes of Characteristics of Tropical Cyclone Rapid Intensification Over Western North Pacific

Abstract

This study investigates the interdecadal variations of rapid intensification (RI) of tropical cyclones (TCs) over Western North Pacific (WNP) during 1960-2016, TC variabilities associated with RI and the possible mechanisms for such variations are also explored. Two RI-active periods (P1:1960-1972, P3:2000-2016) and one RI-inactive period (P2:1973-1999) are identified using Regime Shift Detection method based on the RI-TC ratio data. RI spatial distributions all exhibit a common Main Development Region. Significant different characteristics of the TC genesis and lifetime maximum intensity location are observed between RITCs and Non-RI TCs and in each period. The majority of RITCs starts with initial intensity at 35-80 kts, and P2 shows an obvious displacement of these TC occurrences. The longitudinal distributions of RI ratio demonstrate totally different patterns. The higher SST and relative humidity, as well as stronger VWS, lead to the highest RI ratio in P3. TCs in P2 have less chance to undergo RI due to the eastward extension of monsoon trough associated with a more eastward movement of TC occurrence away from MDR. The environmental conditions are obviously unfavorable for RI in the Western WNP in P2, as well as in P1. Our findings imply that the TC variabilities are affected by the decadal variations of RI events and the changes in TC occurrence along with the RI-favored environmental fields all contribute to the RI variations at interdecadal scales. INDEX TERMS Interdecadal variation, rapid intensification, tropical cyclone, western north pacific.

Decadal changes in rapid intensification of western North Pacific tropical cyclones modulated by the North Pacific Gyre Oscillation

“…Wang et al (2015) found that during the warm (cold) PDO phase, the annual RI number was, on average, lower (higher), and the average RI occurrence position migrated southeastward (northwestward). Zhao et al (2018) and Zhang et al (2020) both found a significantly larger proportion of TCs experiencing RI to the total number of TCs during the cold PDO phase than during the warm PDO phase. During the cold PDO phase, easterly trade winds increased at low levels, leading to a steeper thermocline slope that hampered eastward migration of warm water in the equatorial Pacific.…”

“…The other is a modified MPI calculation where the SST is replaced by the DAT, which includes the effect of ocean cooling (Lin et al 2013, Lee et al 2019. We focus on environmental changes modulated by the NPGO, since PDO-induced environmental changes have been previously studied (e.g., Wang et al 2015, Zhao et al 2018, Zhang et al 2020.…”

“…On decadal-to-multidecadal timescales, WNP RI variability has been linked to phase changes of the Pacific Decadal Oscillation (PDO) (Wang et al 2015, Zhao et al 2018, Zhang et al 2020, Chu and Murakami, 2022. The PDO has been defined as the first empirical orthogonal function (EOF) of North Pacific (20°-70°N) sea surface temperature (SST) anomalies (SSTAs) (Mantua et al 1997, Newman et al 2016.…”

“…Simultaneously, more warm equatorial water spread northward into the main RI region via enhanced meridional ocean advection associated with Ekman transport. This consequently resulted in an oceanic environment with greater TC heat potential (TCHP) and warmer SSTs, favoring RI development (Wang et al 2015, Zhao et al 2018, Zhang et al 2020.…”

Location, Area, Curvature and Temporal Trends of Coral Sea Tropical Cyclone Tracks, Over 50 Years

“…Numerous examples of Southern Hemisphere TC activity analysis (including the South Pacific) using historical cyclone track data exist in recently published scientific literature (e.g., Magee, Verdon-Kidd, Diamond, & Kiem 2017;Bell, Chand, & Turville 2020;Chand et al 2019; (Ramsay, Camargo, & Kim, 2012); Magee, Lorrey, Kiem, & Colyvas 2020;Sharma, Verdon-Kidd, & Magee 2020, 2018Zhao, Zhan, Wang, & Xu 2018). Also, many recent studies using TC track data have been conducted in the Northern Hemisphere (e.g., Bell et al 2020;Bhaskar Rao, Srinivas, & Satyanarayana 2019;Ge & Colle 2019;Kelly et al 2018;Liu, Pan, Huang, Zheng, & He 2019;Zhang, Zhang, Shi, & Yao 2020). However, while historical records of TC tracks as recorded by geo-spatial location has the potential to yield new insight into TC behaviour, the body of research into TC track spatial geometry and curvature and the evolution of these characteristics post genesis is far less prevalent (Sharma, Magee, & Verdon-Kidd 2021).…”