Increased severe landfall typhoons in China since 2004

Abstract

Severe landfall typhoons (SLTYs), defined as those with maximum sustained wind speed ≥41.5 m s −1 at landfalls, strongly affect the coastal regions of China and cause grave losses of life and property. In this study, we analyse the SLTYs in China in peak summer (July-September) for the period of 1973-2017, during which typhoon landfall intensity (LFI) experienced significantly abrupt strengthening in 1987 and 2003. The period is divided into three subperiods: period-I (1973-1987), period-II (1988-2003), and period-III (2004-2017). It is found that the increase in LFI is dominated by the enhancement of intensification rate but not intensification duration. Meanwhile, the SLTYs in China have also abruptly increased since 2004, characterized by the count of about 65.9% (72.7%) of SLTYs in China (South China) in period-III. Further analysis shows that the warming subsurface ocean heat content (OHC) over the northern South China Sea (SCS) plays a key role in modulating typhoon's intensification, which subsequently enhances the easterly steering flow leading typhoons to move westward. Low-level water vapour convergence and vorticity are enhanced accompanied by warming northern SCS along the coastal region of southeastern China, resulting rapid typhoon intensification before landfall. About 9.7% of typhoons with landfall in South China experienced a rapid intensification process in 24 hr before landfalls in period-III. However, the percentage is only 1.6 and 3.1% for period-I and period-II, respectively. The warming land surface over South China plays a minor role in attracting typhoons to landfall in South China, which named as "warmward landfall". Overall, the abrupt enhancement of LFI and more SLTYs in China since 2004 are governed by the warming ocean, while the abnormal easterly steering flow and warming land surface over South China leading typhoons to move westward play a secondary role.

Variability of Tropical Cyclone Landfalls in China

“…Since the TC landfall numbers in southern and southeastern China are relatively stable from 1949 to the end of the twentieth century, track data before 1979, when satellites had not yet been widely available for TC observations, are not used. A transitional period from 1996 to 2001 is also excluded because the effect of the historically massive 1997/98 El Niño event, which has been reported to have an unusual impact on the TC activities over the WNP ocean basin in this period (Iizuka and Matsuura 2008;Liu and Chan 2018;Wu et al 2018;Balmaseda et al 2013;Yao et al 2020). To confirm the robustness of the results on the differences of TC track density over the WNP before and after the abrupt change at the end of twentieth century, we evaluated the deviation caused by a slightly different choice of the dividing year for the two stages.…”

Large-scale atmospheric features favoring the tropical cyclone activity affecting the Guangdong–Hong Kong–Macao Greater Bay Area of China

“…In this study, we only applied the data over the satellite era from 1980 to 2019 when TC data were relatively reliable. Moreover, we focused on the TC activity during peak summer (July-September, JAS) over the WNP (100 • E-180 • , north of the equator), because it is the active TC season for southern China (Zhang et al 2019, Yao et al 2021. To reduce the effect of global warming, we removed the long-term linear trend of the monthly reanalysis data.…”

“…From the annual-mean perspective, the significant poleward and landward migration of TC activity in the past 40 years have been reported, increasing the coastal TC risk of China (Kossin et al 2014, Wu et al 2015, Sharmila and Walsh 2018, Wang and Toumi 2021. In particular, the annual frequency and intensity of the TCs making landfall in southern China exhibit an upward trend during the last decades (Liu and Chan 2018, Shan and Yu 2021, Yao et al 2021. Thus, an improved understanding of the variability of TC activity over southern China is both scientifically and socially important.…”

Increasing compound hazard of landfalling tropical cyclones in China during 1980–2020

“…The rapid development of the Chinese economy has resulted in an increase in the population of coastal areas, which has increased their vulnerability and socio‐economic losses over the past decades (Zhang et al, 2009). Furthermore, activities of the landfalling TCs in China also display striking variability under climate change (Li et al, 2017; Yao et al, 2021). Previous studies suggested that the damaging potential of the TCs in China shows an increasing trend due to their increased mean duration and intensity at landfall (Li et al, 2022; Shan & Yu, 2021).…”