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Typhoons 9117 (.) 9119 and 9918 passed through Kyushu, Chugoku, and Shikoku of Japan in the middle and the latter part of September. Many areas in the western parts of Japan suffered from strong winds and heavy rainfall during the...
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Typhoons 9117 (.) 9119 and 9918 passed through Kyushu, Chugoku, and Shikoku of Japan in the middle and the latter part of September. Many areas in the western parts of Japan suffered from strong winds and heavy rainfall during these typhoons, which damaged crops and greenhouses in these years. The money lost in agriculture in Kyushu, Chugoku, and Shikoku as a result of typhoon 9117 (.) 9119 exceeded 281 billion yen. The money lost in agriculture in these areas as a result of typhoon 9918 exceeded 114 billion yen. Typhoon 9117 (.) 9119 damaged crops, trees, livestock, institutions, and so on. but trees and livestock were not nearly as damaged by typhoon 9918. The crop most damaged by typhoon 9117 (.) 9119 was fruit trees, but the one most damaged by typhoon 9918 was rice. The money lost in rice, vegetables, trees and institutions caused by typhoon 9117 (.) 9119 in this region was more than that caused by typhoon 9918. The difference is attributed to the landing strengths, disaster types, and damage mechanisms of the typhoons.
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We used satellite data, typhoon-resolving atmospheric forcing and a data assimilating ocean model, the East Asian Seas Nowcast/Forecast System (EASNFS), to investigate circulation and three upwelling regions perturbed by tides and...
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We used satellite data, typhoon-resolving atmospheric forcing and a data assimilating ocean model, the East Asian Seas Nowcast/Forecast System (EASNFS), to investigate circulation and three upwelling regions perturbed by tides and Typhoon Fanapi (2010) in the seas around Taiwan. The three upwelling areas located off northeast Taiwan, off southeast China and over the Penghu Channel off southwest Taiwan are normally limited in expanse before Fanapi. The tidal currents enhance all three. To cope with typhoon strength atmospheric forcing, we applied typhoon-resolving Weather Research and Forecasting (WRF) model wind fields that significantly enhanced Fanapi-induced upwelling. Approaching Taiwan, Fanapi induces a cold wake spreading preferably on the right side of the essentially westward running track in the western Pacific. The three upwelling areas in the East China Sea and Taiwan Strait subsequently become expansive as Fanapi approaches and enters the Taiwan Strait. The mechanisms leading to normal or Fanapi-perturbed upwelling and circulation in seas around Taiwan, especially the latter two mentioned above, are suggested. In essence, Fanapi disrupts circulation in the Taiwan Strait, and also the Taiwan Strait outflow entering the East China Sea, leading to expanded upwelling areas. We also suggest that high-resolution wind and tides application is essential for the upwelling modeling study and also the general circulation in the region with and without typhoons.
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This study utilizes the quasi-Lagrangian azimuthal momentum equation (i.e., budget calculation) and 1.667-km-resolution numerical simulation data to study the intensity and structural changes in Hurricane Sandy's extratropical tra...
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This study utilizes the quasi-Lagrangian azimuthal momentum equation (i.e., budget calculation) and 1.667-km-resolution numerical simulation data to study the intensity and structural changes in Hurricane Sandy's extratropical transition. The results indicate that after the onset of extratropical transition, Sandy maintains an eyewall-like convection and warm core in the core region and has a frontal structure in the outer region. In the outer region, baroclinicity-driven frontal convection induces extensive planetary boundary layer (PBL) inflow, causing an inward advection of absolute angular momentum (AAM) per unit radius, which generates outer local wind maxima and expands Sandy's outer wind field through a spinup process. Moreover, because the outer tangential wind velocity accelerates in a frontal convection, local wind maxima associated with fronts can expand to the outer sides of frontal regions. Frontal convection increases AAM in the outer region, providing the precondition for reintensification; however, the front itself cannot cause Sandy's reintensification. The eyewall-like convection in the core region still plays an important role in Sandy's reintensification. When the baroclinic zone, where a strong horizontal temperature gradient exists, approaches the core region, the eyewall-like convection is enhanced because the warm, moist air of the core region is lifted by the cold, dry air associated with the approaching baroclinic zone. Consequently, owing to the enhancement of eyewall-like convection, the PBL inflow, which extends from the outer region to the core region, develops. This inflow increases the inward transportation of the outer frontal region's high-AAM air, thus leading to spinning up the core region's wind and reintensification.
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This study investigated the characteristics of 60 typhoons approaching Japan over the past 14?years (2006–2019) by conducting statistical analysis of their temporal evolution, active hours, intensity, frequency, size, duration, a...
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This study investigated the characteristics of 60 typhoons approaching Japan over the past 14?years (2006–2019) by conducting statistical analysis of their temporal evolution, active hours, intensity, frequency, size, duration, and translation speed. By dividing the time period into the earlier (before 2012) and the most recent (after 2013) years, the analysis indicated that the annual frequency of typhoons is higher in the most recent years than in the earlier years. The typhoons in recent years took relatively less time to reach Japan and remained active for shorter time over the land are of Japan than those in the earlier years. The intensity of the typhoons in the recent years showed stronger winds and considerably lower pressures at the landfall time than that in the earlier years. Typhoons in recent years carry more frequent and intense rainfall compared to those in the earlier years in this study. The analysis inferred that the higher sea surface temperature, weaker vertical wind shears, and a larger amount of moisture around the centers of the recent typhoons were responsible for making them stronger.
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Typhoon Haiyan hit the Philippines in 2013, causing billions in damage, and taking thousands of lives. Media and researchers claimed that people did not have enough information about the storm, or did not understand the informatio...
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Typhoon Haiyan hit the Philippines in 2013, causing billions in damage, and taking thousands of lives. Media and researchers claimed that people did not have enough information about the storm, or did not understand the information given to them, and therefore did not evacuate. This research departs from the assumption of a knowledge deficit: it asks how people understood warnings and how information flowed from the government. This research focuses on Guiuan, a municipality that sustained heavy damage and loss of life, and the entry point of many typhoons in the Philippines. Guided by Stuart Hall's Encoding-Decoding Theory, the researcher carried out focus group discussions with citizens and interviews with local government officials from one coastal and one inland village. Through systematic qualitative analysis of interviews and discussions, the researcher found that participants from different locations in the same municipality understood warning information differently, based on unique epistemological frames. While local government framed people as deficient in knowledge, the citizens actually called upon their previous experiences with storms in order to make evacuation decisions. However, they could not project worse scenarios from previous experience and needed a phenomenon to match an experience in real time before making an evacuation decision. These findings imply that disaster imagination, disaster memory, and disaster knowledge are all distinct concepts, and future research should examine how specific contexts frame risk. Early warning systems for storms must also take into account unique epistemological frames as a means to localize communication and engage communities in the decision-making process.
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Surprisingly, on 27 December 2001, a storm named Typhoon Vamei formed near in Singaporean waters. An examination on the SSM/I-derived rainfall rates and air-sea parameters showed that significant higher latent heat release and air...
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Surprisingly, on 27 December 2001, a storm named Typhoon Vamei formed near in Singaporean waters. An examination on the SSM/I-derived rainfall rates and air-sea parameters showed that significant higher latent heat release and air-sea energy flux during convective rainfall activities played a key role in the typhoon's growth. A quantitative analysis revealed that the energy flux from the ocean to the atmosphere and the latent heat release during the rainfall activities both increased significantly during the initial growth stage. However, the values rapidly decreased just before the storm reached typhoon strength. Separately, in contrast to a case that occurred in 1999, the total thermal energy calculated from Typhoon Vamei's formation was two times higher. Thus, despite a very weak Coriolis force in the equatorial belt, the special terrain of Borneo Island and narrow channel in the equatorial South China Sea caused a Borneo vortex via northeasterly cold surges, together with the accumulated energy was sufficiently strong enough to induce the formation of Typhoon Vamei.
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The major purpose of this study was to develop a predictive model of the yearly frequency of typhoon. Based on historical data, a predictive model of yearly frequency of typhoon that landed in South China was pro- Posed during the...
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The major purpose of this study was to develop a predictive model of the yearly frequency of typhoon. Based on historical data, a predictive model of yearly frequency of typhoon that landed in South China was pro- Posed during the season of typhoon using the basic thinking and its algorithm of Projection Pursuit Regression (PPR). The results show that the predictive precision of PPR model is much better than that of stepwise regres- sion (SR) model.
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Analyzing the typhoon wind hazards is crucial to determine the extreme wind load on engineering structures in the typhoon prone region. In essence, the typhoon hazard analysis is a high-dimensional problem with randomness arising ...
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Analyzing the typhoon wind hazards is crucial to determine the extreme wind load on engineering structures in the typhoon prone region. In essence, the typhoon hazard analysis is a high-dimensional problem with randomness arising from the typhoon genesis, environmental variables and the boundary layer wind field. This study suggests a dimension reduction approach by decoupling the original typhoon hazard analysis into two stages. At the first stage, the randomness of the typhoon genesis and environmental variables are propagated through the typhoon track model and intensity model into the randomness of the key typhoon parameters. At the second stage, the probability distribution information of the key typhoon parameters, combined with the randomness of the boundary layer wind field, could be used to estimate the extreme wind hazard. The Chinese southeast coastline is taken as an example to demonstrate the adequacy and efficiency of the suggested decoupling approach.
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In two successive years, 2017 and 2018, Macau suffered tremendously from strong typhoons, Hato and Mangkhut, respectively. Following Hato in 2017, a top officer who served as the observatory's director, resigned amid public compla...
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In two successive years, 2017 and 2018, Macau suffered tremendously from strong typhoons, Hato and Mangkhut, respectively. Following Hato in 2017, a top officer who served as the observatory's director, resigned amid public complaints over the late issuance of a higher warning signal during the typhoon. In light of this general disappointment in Macau's disaster preparation and response procedures, we conducted an interview survey in downtown Macau. Our survey aimed to determine whether people felt any noticeable improvement in the authority's disaster response during Mangkhut in 2018, compared to the response during Hato. The typhoons were of similar intensity and followed similar paths. The most notable difference between the two disasters was that Signal 8 was triggered seven hours earlier for Mangkhut than Hato, demonstrating a remarkable difference in the precaution and response taken by the authority. 18 months after Hato, we did not observe a significant investment in public infrastructure for flood protection. However, 88% of the respondents replied that they perceived that there was an improvement in the authority's disaster response and management. Soft countermeasures, such as warning boards, evacuation drills, prompt signal issuance, and emergency responses, might be responsible for the favourable perception among the local residents.
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