[1] Tropical cyclone (TC) damage is closely associated with the time TCs spend over land. After examining 233 TCs that formed over the western North Pacific and then made landfall over China mainland during 1951China mainland during -2009, this study shows a significant increase in the annual average overland duration of a TC over the past 35 years from 1975 to 2009, while no significant trend can be detected in the annual frequency. The increasing duration over land is consistent with the increasing rainfall associated with the landfall TCs and changes in the large-scale steering flow. It seems that the decreasing vertical wind shear allows the landfall TCs to increase survival time over land during the past 35 years.
The torrential-rainfall-associated tropical cyclone (TC) activity often causes flood disasters in China. Moreover, studies suggest that TC-related rainfall rates are likely to increase in a warmer climate. Using daily precipitation observations at 514 meteorological stations during 1965̶2009, this study investigates the primary features of TC rainfall in China, with a particular focus on the contribution of TC rainfall to the changes in the precipitation climate and the average rainfall per TC.TC rainfall mainly affected eastern and southeastern China, accounting for more than 10% of the summer rainfall in South and Southeast China. TC rainfall trended upward in the lower reach of the Yangtze River and Southeast China, contributing to the "wetting in the south and drying in the north" pattern by enhancing the rainfall in Southeast China. This study suggests that the average rainfall per TC has significantly increased in Southeast China during 1965̶2009. In the peak season (July̶September), all significant changes are upward trends that occur south of the Yangtze River east of 110°E. This study finds that the increasing rainfall per TC was not accompanied with the enhanced TC intensity. In addition, no significant trend can be found in the translation speed of TCs that affected China during 1965̶2009, suggesting that the increasing TC rainfall per TC in China was not due to the slowdown of TC movement.
Objective: Lianhua Qingwen combined with Western medicine (LHQW+WM) has been proposed as a viable treatment for coronavirus disease 2019 . Interestingly, umbrella reviews of systematic reviews (SRs), which provide the most comprehensive evidence, are the best evidence in evidence-based medicine. Therefore, an umbrella review of SRs that summarizes and evaluates the efficacy of LHQW+WM for COVID-19 is urgently required.Methods: Overall, 6 databases were used to conduct a comprehensive literature search from inception to January 22, 2022. The corrected covered area (CCA) was used to analyze the overlapping between SRs. Meta-analysis was conducted when that of the included SRs was inappropriate. A MeaSurement Tool to Assess Systematic Reviews (AMSTAR-2) was also employed to assess the quality of the included SRs.Results: In total, 12 SRs were identified, which included 12 unique primary studies. The included SRs ranged in quality from moderate to critically low and had an extremely high CCA (36.4%). Compared to conventional treatment, LHQW+WM showed efficacy concerning fatigue recovery [risk ratio (RR) = 1.69, 95% confidence interval (CI): 1.04-2.73, n = 2, I 2 = 0%], cough recovery (RR = 1.65, 95% CI: 1.09-2.51, n = 3, I 2 = 39.1%), and overall effective rates (RR = 1.17, 95% CI: 1.07-1.28, n = 3, I 2 = 17.5%).Conclusion: LHQW+WM may improve the clinical symptoms of patients with COVID-19; however, the results should be interpreted cautiously because of the rigorous processes in the included SRs.
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