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This study investigates the main climatological features of extreme precipitation (TCER) induced by tropical cyclones (TCs) affecting Guangxi (GX), South China using multiple datasets and a 99th percentile threshold during 1981–2020, with an emphasis on the rainfall diversities of different high-impact TC groups and their associated mechanisms. Results show that there are large regional differences and a seasonal imbalance in the climatological features of TCER in GX. In summer (fall), TCs with TCER events primarily move northward or eastward (northwestward or westward), namely, S-NWTCs and S-ETCs (F-WTCs and F-NWTCs). The rainfall centers exhibit asymmetrical features with S-NWTCs and F-NWTCs located in the northeast quadrant, but S-ETCs and F-WTCs in the southwest and northeast quadrants, respectively. Comparisons of atmospheric circulations and environmental factors indicate that the intense rainfall of F-WTCs is mainly attributed to the trough–TC interaction, which is accompanied by stronger upper-level westerly jet and cold air intrusion, thus increasing baroclinic energy and uplifting for the strongest rainfall among these four groups. This interaction is absent for other groups due to a greater South Asian high and western North Pacific subtropical high. Instead, the increased rainfall in S-NWTCs and F-NWTCs can mainly be attributed to the stronger low-level southwesterly jet, which, in combination with low-level warm advection and convergence induced by land–sea friction, promotes the release of latent heat through moisture condensation. S-ETCs differ from S-NWTCs and F-NWTCs in that moisture convergence is weaker due to the much-weakened TC circulation. [ABSTRACT FROM AUTHOR]

The characteristics of landfalling severe typhoons (LSTYs)—i.e., typhoons with landfall intensities of 2 min with a mean maximum sustained wind ≥41.5 m s−1—in South China (SC) were here examined. Thirteen LSTYs have been recorded in SC since 1949, and most of them underwent a rapid intensification before landfall. The LSTYs were classified into three categories based on the intensity of the western North Pacific summer monsoon, i.e., as weak, moderate, and strong monsoons. The characteristics of the three types of LSTYs are markedly different. Two LSTYs (7317 and 1523) were developed against a weak monsoon (WM) background and did not have abundant monsoon water vapor drawn into the typhoon cores. Therefore, these two LSTYs exhibited smaller horizontal outer sizes and weaker "warm–wet" cores than those in moderate and strong monsoons. However, a warm offshore ocean supplied a sufficient amount of energy, favoring these two LSTYs' rapid intensification before landfall. There have been five LSTYs (9113, 0518, 0816, 1320, and 1826) that formed under strong monsoon (SM) conditions but obtained a poor energy supply from the coastal ocean. Embedded in the SM, the vigorous warm–wet monsoon flow was drawn into the typhoons and persisted for several days until landfall. Then, the five LSTYs developed strongly at the greatest horizontal scale and were maintained as severe typhoons for almost 48 h before landfall. The beneficial warm–wet atmospheric circulation stimulated the strongest warm (wet) core at the upper (lower) level of the LSTYs, and a secondary, low-level warm core occurred as well. In moderate monsoon (MM) cases (8106, 9617, 1311, 1410, 1418, and 1714), the strength of the monsoon flow, the "warm–wet" core of the typhoon, and the ocean energy supply were ranked just between those of the LSTYs in WMs and SMs. The development of the LSTYs in the MM cases resulted from a combination of the effects of monsoon and ocean energy supply. In addition, the powerful upper-level divergence ascribed to the strong South Asia High may have played an auxiliary role in MM cases. From the perspective of the sea surface temperature (SST) response to the LSTYs, because of a relatively fast translation speed and the warmer subsurface ocean, the SST cooling was weakest for WM cases. However, the strongest SST cooling was found in SM cases and it was partially due to their slowest translation speed. [ABSTRACT FROM AUTHOR]

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 sub‐periods: 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. [ABSTRACT FROM AUTHOR]

Increasing intense landfalling typhoons (LFTYs) are of great coastal threatens to southern China. However, changes in genesis location and landfalling frequency of western North Pacific (WNP) LFTY dedicated to southern China remain unclear. Here we identified such LFTYs during peak summer and found that most LFTYs formed south of 20°N and the LFTY genesis locations over southern WNP have also experienced a sharp interdecadal shift since 1998, which are mainly attributed to the large‐scale environment changes induced by the Mega‐La Niña‐like climate shift. However, LFTY frequency (= "landfalling frequency of southern China typhoon") shows a slight increasing trend but without significant interdecadal variation. Variations of LFTY frequency are mainly affected by the easterly steering flows near 20°N over the South China Sea and the Philippine Sea, which are closely linked to the WNP subtropical high activity. Our results provide a new perspective on the LFTY activities dedicated to southern China. Plain Language Summary: We explore the changes in frequency and genesis location of landfalling typhoon (LFTY) dedicated to southern China during peak summer over 1979–2015, which is important for people's life and property from the coastal risk perspective. Results show that the LFTY genesis location is primarily modulated by the Pacific interdecadal variation via modifying the large‐scale atmospheric and oceanic responses over the western North Pacific. While the LFTY frequency (= "landfalling frequency of southern China typhoon") is significantly affected by the easterly steering flows near 20°N over the South China Sea and the Philippine Sea, which are closely linked to the western North Pacific subtropical high activity. Key Points: Landfalling frequency and genesis location of southern China typhoon are affected by different mechanisms during peak summerInterdecadal changes in landfalling typhoon (LFTY) genesis location are primarily attributed to the late‐1990s Mega‐La Niña‐like regime shiftVariations of LFTY frequency are mainly driven by the easterly steering flows near 20°N associated with the western North Pacific subtropical high activity [ABSTRACT FROM AUTHOR]

Based on multiple datasets, a comparative analysis has investigated the different rainfall distributions and the factors related to strong (weak) rainfall induced by landfalling strong typhoons moving northwest (SR-NWLFSTYs, WR-NWLFSTYs) which are defined from the tracks, the locations, and intensities of the rainfall center of LFSTYs based on a dynamic composite analysis method. The obviously stronger rainfall induced by SR-NWLFSTYs, with the intensive rainfall center presenting a cyclonic rotation in the lifecycle of typhoons, tends to be accompanied by the pronouncedly enhanced low-level jet and a warmer SST before and during landfall. Owing to the enhanced low-level jet, moisture convergence experiences an intensification, resulting in a warmer and more humid circulation. Sufficient water vapor and latent heat is favorable for the enhancement of the mid-troposphere warm core structure with longer maintenance which can prolong the impact period of typhoons, leading to continuous precipitation. Simultaneously, the coupling of low-level convergence and upper-level divergence provides favorable dynamic conditions, thus further promoting the upward transportation of moisture through Ekman pumping, which tends to increase the mid-troposphere moisture through moisture advection. The changes in the mid-troposphere moisture coincide well with the evolution of rainfall over the same region during the lifecycle of typhoons. Comparatively, the asymmetric rainfall features of WR-NWLFSTYs with intense rainfall center mainly placed in the northeast quarter of the TC center during the lifecycle of TCs is likely related to the relatively weaker low-level jet which remains almost constant during and after landfall. The weaker low-level flow transports less moisture into the cyclone, and prohibits the weakening of vertical wind shear after landfall, leading to reduced precipitation with an obvious asymmetric distribution. Concurrently, the configuration of the weakening upper-level divergence and low-level convergence after landfall has been unable to maintain the upward motion for precipitation, resulting in relatively weaker rainfall for WR-NWLFSTYs. • The evolution and primary possible mechanisms of the different precipitation distributions before, during, and after landfall of three types of landfalling strong typhoons (LFSTYs) over South China were investigated. • The different intensities of low-level jets corresponded to different possible dynamic mechanisms of precipitation evolutions for two main types of LFSTYs. [ABSTRACT FROM AUTHOR]

An analysis of high-resolution precipitation data for 1978-2006 indicates that the precipitation over southern China in June experienced a low-value period in 1980-1989 and a high-value period in 1992-2001. It also reveals that exceptional heavy (light) precipitation occurred in June 2005 (2004) since 1951. For these variations on both interdecadal and interannual timescales, fairly uniform anomalies of precipitation appeared over Vietnam, southern China, and southeastern China. Corresponding to positive (negative) precipitation anomalies, anomalous southeasterly (northwesterly) flow at 850 hPa reached Vietnam and anomalous southwesterly (northeasterly) flow expanded to the coastal regions of southern and southeastern China. Precedent to the positive (negative) precipitation anomalies during 1992-2001 (1980-1989), positive (negative) anomalies of sea surface temperature appeared over the extratropical northwestern Pacific in the winter and spring seasons, associated with a strong (weak) extension of the warm Kuroshio Current that affects the coastal region of eastern China. The above-normal precipitation in June 2005 was associated with the pseudo-ENSO event in the previous winter, and the below-normal precipitation in June 2004 was associated with negative anomalies of sea surface temperature over the equatorial central Pacific and positive anomalies over the equatorial western and eastern Pacific. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of body mass index (BMI) and waist circumference (WC) on metabolic health risks (MHR)., Methods: Based on data from two community populations (Suzhou city and Changshu city) derived from a project on 'multiple metabolic disorders and metabolic syndrome' in Jiangsu province. 1604 subjects were divided into groups as normal weight (BMI: 18-23.9), overweight (BMI: 24-27.9) and obesity (BMI > or = 28) according to BMI measurement. According to the results from WC measurement, they were grouped as abdominal obesity (male: > or = 85 cm; female: > or = 80 cm) and normal. Relative risks (RR) for hypertension, hyperglycemia, dyslipidemia were calculated., Results: In males and females, the mark values of hypertension, hyperglycemia, dyslipidemia as well as the prevalence of MS were related to BMI and WC. The relativity remained true when the confounding factors were under control. Among the overweight group, the aRR of all these metabolic health risks were basically lower than those when the overweight group and the abdominal obesity group were combined. Both in males and females, when groups combining normal weight with abdominal obesity group, the aRR of all these metabolic health risks were higher than overweight group combining with normal WC group in most of the cases., Conclusion: As to the effect of BMI and WC on metabolic health risks, WC--the mark of abdominal obesity seemed to be more effective than BMI.