Pub Date : 2024-12-01DOI: 10.1016/j.tcrr.2024.11.006
Jeff Callaghan
Recent intensifying tropical cyclones around the globe are analysed to examine the observed winds structure in their inner core. The winds in sectors with strong bands of thunderstorms were observed from analysed vector winds in weather forecasting computer models to turn in an anticyclonic fashion from the 850 hPa level up to the 500 hPa level. This wind structure resembles Quasi-Geostrophic warm air advection and from Hysplit the trajectory analysis was in areas of ascending air currents suitable for the initiation of thunderstorms. The rapid intensification occurred as the cyclonic circulation extends up to at least 200 hPa.
{"title":"Development of strong asymmetric convection leading to rapid intensification of tropical cyclones","authors":"Jeff Callaghan","doi":"10.1016/j.tcrr.2024.11.006","DOIUrl":"10.1016/j.tcrr.2024.11.006","url":null,"abstract":"<div><div>Recent intensifying tropical cyclones around the globe are analysed to examine the observed winds structure in their inner core. The winds in sectors with strong bands of thunderstorms were observed from analysed vector winds in weather forecasting computer models to turn in an anticyclonic fashion from the 850 hPa level up to the 500 hPa level. This wind structure resembles Quasi-Geostrophic warm air advection and from Hysplit the trajectory analysis was in areas of ascending air currents suitable for the initiation of thunderstorms. The rapid intensification occurred as the cyclonic circulation extends up to at least 200 hPa.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 4","pages":"Pages 239-260"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143307916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.tcrr.2024.11.002
Zeng Jinyu , Lian Chenfang , Yin Siyu , Sun Chaofeng
<div><div>Based on wind profile radar data, this paper aims at different typhoon processes landed and affected Fujian from 2011 to 2019, according to the nature of typhoon rainstorm, it can be classified into outer precipitation before typhoon landed, main body precipitation and precipitation at the rear of typhoon, the change of the characteristic quantities in approaching time of the occurrence of short-term heavy rainfall was analyzed, and the typhoon case in 2020 was back calculated. The results show that, the characteristics of low-level jet streams (maximum wind speed at low altitude, minimum height of jet streams, and low-level jet stream index), as well as the magnitude of vertical wind shear below 700 hPa, have important indicative significance for the occurrence of short-term heavy rainfall. (1) More than 80 % of short-term heavy rainfall occurred 3 h before the low-level jet stream already existed. The maximum wind speed below 2 km was basically close to a normal distribution, and the occurrence of heavy precipitation showed a bimodal pattern. The percentage of wind speed between 8 and 32 m/s was the highest, exceeding 85 %. The wind direction of the strong wind is mainly NE, SE, and SW. Classification analysis showed that the distribution characteristics of wind speed of the main precipitation were the same as before, but the wind direction SE was higher than NE. The wind speed of pre-landfall precipitation was basically skewed, and the occurrence time of heavy precipitation followed a normal distribution. The percentage of wind speed between 16 and 32 m/s was the highest, and the wind direction was the same as before classification. The maximum wind speed of precipitation in the rear was basically bimodal distribution, with a relatively even distribution, and the wind direction was mainly SE and SW. (2) In the 3 h before the occurrence of short-term heavy precipitation, there was an increase in the maximum wind speed value, a decrease in the minimum extension height, and an increase in the low-level jet stream index I. As short-term heavy rainfall approached, the intensity of the low-level jet stream remained high and its proportion increased. The minimum achievable extension height gradually decreased and remained stable at a low value. In the first 2 h of heavy rainfall, the wind speed reached its maximum, the extension height was the lowest, and the low-level jet stream index I was the highest. Classifying and discussing it, the precipitation in the rear was different, and the lowest height decreased to the lowest at the time of occurrence, at which point the I value reached its maximum. The characteristics of the other two categories were the same as before the classification. (3) The vertical wind shear from the ground to different isobaric surfaces gradually decreased with the increase of height. With the approach of short-term heavy rainfall, the vertical wind shear of each layer basically decreased gradually, after the beginn
{"title":"Application research of wind profile radar in short-term heavy rainfall forecast of typhoon in Fujian Province","authors":"Zeng Jinyu , Lian Chenfang , Yin Siyu , Sun Chaofeng","doi":"10.1016/j.tcrr.2024.11.002","DOIUrl":"10.1016/j.tcrr.2024.11.002","url":null,"abstract":"<div><div>Based on wind profile radar data, this paper aims at different typhoon processes landed and affected Fujian from 2011 to 2019, according to the nature of typhoon rainstorm, it can be classified into outer precipitation before typhoon landed, main body precipitation and precipitation at the rear of typhoon, the change of the characteristic quantities in approaching time of the occurrence of short-term heavy rainfall was analyzed, and the typhoon case in 2020 was back calculated. The results show that, the characteristics of low-level jet streams (maximum wind speed at low altitude, minimum height of jet streams, and low-level jet stream index), as well as the magnitude of vertical wind shear below 700 hPa, have important indicative significance for the occurrence of short-term heavy rainfall. (1) More than 80 % of short-term heavy rainfall occurred 3 h before the low-level jet stream already existed. The maximum wind speed below 2 km was basically close to a normal distribution, and the occurrence of heavy precipitation showed a bimodal pattern. The percentage of wind speed between 8 and 32 m/s was the highest, exceeding 85 %. The wind direction of the strong wind is mainly NE, SE, and SW. Classification analysis showed that the distribution characteristics of wind speed of the main precipitation were the same as before, but the wind direction SE was higher than NE. The wind speed of pre-landfall precipitation was basically skewed, and the occurrence time of heavy precipitation followed a normal distribution. The percentage of wind speed between 16 and 32 m/s was the highest, and the wind direction was the same as before classification. The maximum wind speed of precipitation in the rear was basically bimodal distribution, with a relatively even distribution, and the wind direction was mainly SE and SW. (2) In the 3 h before the occurrence of short-term heavy precipitation, there was an increase in the maximum wind speed value, a decrease in the minimum extension height, and an increase in the low-level jet stream index I. As short-term heavy rainfall approached, the intensity of the low-level jet stream remained high and its proportion increased. The minimum achievable extension height gradually decreased and remained stable at a low value. In the first 2 h of heavy rainfall, the wind speed reached its maximum, the extension height was the lowest, and the low-level jet stream index I was the highest. Classifying and discussing it, the precipitation in the rear was different, and the lowest height decreased to the lowest at the time of occurrence, at which point the I value reached its maximum. The characteristics of the other two categories were the same as before the classification. (3) The vertical wind shear from the ground to different isobaric surfaces gradually decreased with the increase of height. With the approach of short-term heavy rainfall, the vertical wind shear of each layer basically decreased gradually, after the beginn","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 4","pages":"Pages 261-275"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143307917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.tcrr.2024.11.008
Zaine Perry , Ramontsheng Rapolaki , Sarah Roffe , Moagabo Ragoasha
During February–March 2023, the record-breaking tropical cyclone (TC) Freddy caused widespread flooding and damages across southeastern Africa. While <5 % of TCs make landfall into southern Africa, TC Freddy made landfall twice and is the only TC in the past two decades that has tracked over 8000 km across the entire southern Indian Ocean. To understand why TC Freddy was so unique, this study investigated the evolution, track and atmospheric-oceanic mechanisms driving TC Freddy using the ERA5, CFSv2, OSTIA, NCEP-NCAR datasets and track data from various sources. It was found that SSTs were >27 °C during TC Freddy’s lifetime, while TC Dingani and a split Mascarene High played a role in steering TC Freddy across the southern Indian Ocean. Leading up to the development of TC Freddy, conditions were favourable for TC genesis, as indicated by the levels of the Genesis Potential Parameter (GPP) and its modified version (GPPI), the tropical cyclone heat potential levels, and elevated SSTs. Ridging subtropical anticyclones and the Mascarene High alongside favourable steering flow and GPP (and GPPI) conditions resulted in Freddy’s double landfall in Mozambique. In assessing the tracks, it was found that there are discrepancies in the track of the commonly used IBTrACS when compared to ERA5 and RSMC tracks, which has implications for impact studies due to the underestimation of landfall considerations. This study reveals the unique characteristics and atmospheric-oceanic mechanisms driving TC Freddy, emphasising the importance of accurate representation of favourable conditions and track data for enhancing TC forecasting and impact assessments.
{"title":"Analysing the atmospheric-oceanic conditions driving the sustained long track and intensity of Tropical Cyclone Freddy","authors":"Zaine Perry , Ramontsheng Rapolaki , Sarah Roffe , Moagabo Ragoasha","doi":"10.1016/j.tcrr.2024.11.008","DOIUrl":"10.1016/j.tcrr.2024.11.008","url":null,"abstract":"<div><div>During February–March 2023, the record-breaking tropical cyclone (TC) Freddy caused widespread flooding and damages across southeastern Africa. While <5 % of TCs make landfall into southern Africa, TC Freddy made landfall twice and is the only TC in the past two decades that has tracked over 8000 km across the entire southern Indian Ocean. To understand why TC Freddy was so unique, this study investigated the evolution, track and atmospheric-oceanic mechanisms driving TC Freddy using the ERA5, CFSv2, OSTIA, NCEP-NCAR datasets and track data from various sources. It was found that SSTs were >27 °C during TC Freddy’s lifetime, while TC Dingani and a split Mascarene High played a role in steering TC Freddy across the southern Indian Ocean. Leading up to the development of TC Freddy, conditions were favourable for TC genesis, as indicated by the levels of the Genesis Potential Parameter (GPP) and its modified version (GPPI), the tropical cyclone heat potential levels, and elevated SSTs. Ridging subtropical anticyclones and the Mascarene High alongside favourable steering flow and GPP (and GPPI) conditions resulted in Freddy’s double landfall in Mozambique. In assessing the tracks, it was found that there are discrepancies in the track of the commonly used IBTrACS when compared to ERA5 and RSMC tracks, which has implications for impact studies due to the underestimation of landfall considerations. This study reveals the unique characteristics and atmospheric-oceanic mechanisms driving TC Freddy, emphasising the importance of accurate representation of favourable conditions and track data for enhancing TC forecasting and impact assessments.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 4","pages":"Pages 356-388"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143308166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.tcrr.2024.11.004
Kin Sik Liu , Johnny C.L. Chan , Bruce Chong , Homan Wong
This study reveals the possible future changes in tropical cyclone (TC) landfalling activity along the East Asian coast under different climate change scenarios based on global circulation model (GCM) simulations. We first identify those GCMs that have the “best” performance in simulating the TC activity over the western North Pacific (WNP) during the current climate (1979–2014) by examining the simulated TCs in each of the GCMs and then compare these simulated TCs with the observed TC climatological features of annual frequency, track densities and genesis locations. Based on such comparisons, we have identified five (TaiESM1, EC-Earth3, ACCESS-CM2, ACCESS-ESM1-5 and HadGEM3-GC31-LL) models among all the available GCMs. A multi-model ensemble gives a further improvement when compared with observations.
Future projections from some of these models are then used to identify the frequency of TC activity over the entire WNP as well as landfalling TCs in six East Asia coastal regions under two climate change scenarios (SSP2-4.5 and SSP5-8.5) for two periods, 2041-70 and 2071-2100. A bias-correction method is also applied to the projected intensity of these landfalling TCs to estimate the landfall intensity.
In general, these GCMs project a possible decrease in TC genesis frequency over the entire WNP, consistent with the results of most of the other studies. At mid-century, decreases in TC genesis frequency are projected to be around 10% for both scenarios. Towards the end of the century, the decreases will be more significant, with the percentage changes of 14.9% (SSP2-4.5) and 22.4% (SSP5-8.5). For landfalling TCs, the northern part of the East Asian coast will likely have an increase in frequency, ranging from 17 to 60% but a decrease of 14–27% in the southern part. In general, the average intensity of landfalling TCs will likely increase although the percentages are not large, ranging from 2 to 14%.
{"title":"Projections of future tropical cyclone landfalling activity in the East Asia region","authors":"Kin Sik Liu , Johnny C.L. Chan , Bruce Chong , Homan Wong","doi":"10.1016/j.tcrr.2024.11.004","DOIUrl":"10.1016/j.tcrr.2024.11.004","url":null,"abstract":"<div><div>This study reveals the possible future changes in tropical cyclone (TC) landfalling activity along the East Asian coast under different climate change scenarios based on global circulation model (GCM) simulations. We first identify those GCMs that have the “best” performance in simulating the TC activity over the western North Pacific (WNP) during the current climate (1979–2014) by examining the simulated TCs in each of the GCMs and then compare these simulated TCs with the observed TC climatological features of annual frequency, track densities and genesis locations. Based on such comparisons, we have identified five (TaiESM1, EC-Earth3, ACCESS-CM2, ACCESS-ESM1-5 and HadGEM3-GC31-LL) models among all the available GCMs. A multi-model ensemble gives a further improvement when compared with observations.</div><div>Future projections from some of these models are then used to identify the frequency of TC activity over the entire WNP as well as landfalling TCs in six East Asia coastal regions under two climate change scenarios (SSP2-4.5 and SSP5-8.5) for two periods, 2041-70 and 2071-2100. A bias-correction method is also applied to the projected intensity of these landfalling TCs to estimate the landfall intensity.</div><div>In general, these GCMs project a possible decrease in TC genesis frequency over the entire WNP, consistent with the results of most of the other studies. At mid-century, decreases in TC genesis frequency are projected to be around 10% for both scenarios. Towards the end of the century, the decreases will be more significant, with the percentage changes of 14.9% (SSP2-4.5) and 22.4% (SSP5-8.5). For landfalling TCs, the northern part of the East Asian coast will likely have an increase in frequency, ranging from 17 to 60% but a decrease of 14–27% in the southern part. In general, the average intensity of landfalling TCs will likely increase although the percentages are not large, ranging from 2 to 14%.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 4","pages":"Pages 328-343"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143307920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.tcrr.2024.11.005
Anupama Sahoo , M.S. Girishkumar
Tropical cyclones (TCs) create more disasters when they make landfall. Climatologically, the west coast of the Bay of Bengal (BoB), one of the most densely populated geographical regions over the globe, is more vulnerable to TC landfall during the primary TC season (October–December), with around 72% of TCs originating in the BoB making landfall on the west coast of BoB (WCBoB). However, the evidence for reliable interannual modulation of sub-seasonal variability on landfalling TCs during the primary TC season in the BoB has been explored less. Here, we used the 35 years (1988–2022) of best TC track data from the BoB to investigate this aspect. Those TCs that made landfall on the WCBoB indicate a significant meridional shift between the first and second half of the primary TC season in the La Niña regime, with 93% (83%) of TC formed in the first (second) half of the season making landfall in the north WCBoB (south WCBoB). Our study reveals that the meridional shift in genesis location and difference in steering flow between the first and second halves of the season is principally responsible for the sub-seasonal variability of landfall location in the La Niña regime, in which former characteristics seem to be determined by southward propagation of Genesis Potential Index (GPI). GPI magnitude is lower in the El Niño regime than in the La Niña regime during the primary TC season, resulting in lower TC activity without sub-seasonal variability in the landfall characteristics in the BoB.
{"title":"Sub-seasonal variability of tropical cyclone landfall characteristics on the west coast of the Bay of Bengal during October–December: The role of La Niña and El Niño","authors":"Anupama Sahoo , M.S. Girishkumar","doi":"10.1016/j.tcrr.2024.11.005","DOIUrl":"10.1016/j.tcrr.2024.11.005","url":null,"abstract":"<div><div>Tropical cyclones (TCs) create more disasters when they make landfall. Climatologically, the west coast of the Bay of Bengal (BoB), one of the most densely populated geographical regions over the globe, is more vulnerable to TC landfall during the primary TC season (October–December), with around 72% of TCs originating in the BoB making landfall on the west coast of BoB (WCBoB). However, the evidence for reliable interannual modulation of sub-seasonal variability on landfalling TCs during the primary TC season in the BoB has been explored less. Here, we used the 35 years (1988–2022) of best TC track data from the BoB to investigate this aspect. Those TCs that made landfall on the WCBoB indicate a significant meridional shift between the first and second half of the primary TC season in the La Niña regime, with 93% (83%) of TC formed in the first (second) half of the season making landfall in the north WCBoB (south WCBoB). Our study reveals that the meridional shift in genesis location and difference in steering flow between the first and second halves of the season is principally responsible for the sub-seasonal variability of landfall location in the La Niña regime, in which former characteristics seem to be determined by southward propagation of Genesis Potential Index (GPI). GPI magnitude is lower in the El Niño regime than in the La Niña regime during the primary TC season, resulting in lower TC activity without sub-seasonal variability in the landfall characteristics in the BoB.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 4","pages":"Pages 276-285"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143354297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.tcrr.2024.11.001
Jeferson Zerrudo, Sharon Juliet Arruejo
This study introduces the ‘Zero-Point Boundary’ method to map the 2013 Typhoon Haiyan storm surge in coastal eastern Leyte. Utilising the ‘Rivera Dispersive Wave Model’ or RDM, we interpolated simulated storm surge and wave height data, subtracting them from a 5-m resolution digital terrain model raster provided by the National Mapping and Resource Information Authority (NAMRIA) to determine inundation limits and depths relative to the average Filipino male height (i.e., 165 cm). Validation against the 2013 joint survey conducted by the Japan Society of Civil Engineers (JSCE) and the Philippine Institute of Civil Engineers (PICE) showed an 81 % accuracy rate when identifying water limit locations in Tacloban City, suggesting potential for future forecasting. However, the absence of compound flooding consideration in the simulations may have influenced this rate. Overall, this study underscores the importance of accurate modelling and communication in hazard mapping for enhancing preparedness and mitigation efforts, emphasising a balanced approach to risk perception.
{"title":"Hindcasting the typhoon haiyan storm surge in coastal eastern leyte","authors":"Jeferson Zerrudo, Sharon Juliet Arruejo","doi":"10.1016/j.tcrr.2024.11.001","DOIUrl":"10.1016/j.tcrr.2024.11.001","url":null,"abstract":"<div><div>This study introduces the ‘Zero-Point Boundary’ method to map the 2013 Typhoon Haiyan storm surge in coastal eastern Leyte. Utilising the ‘Rivera Dispersive Wave Model’ or RDM, we interpolated simulated storm surge and wave height data, subtracting them from a 5-m resolution digital terrain model raster provided by the National Mapping and Resource Information Authority (NAMRIA) to determine inundation limits and depths relative to the average Filipino male height (i.e., 165 cm). Validation against the 2013 joint survey conducted by the Japan Society of Civil Engineers (JSCE) and the Philippine Institute of Civil Engineers (PICE) showed an 81 % accuracy rate when identifying water limit locations in Tacloban City, suggesting potential for future forecasting. However, the absence of compound flooding consideration in the simulations may have influenced this rate. Overall, this study underscores the importance of accurate modelling and communication in hazard mapping for enhancing preparedness and mitigation efforts, emphasising a balanced approach to risk perception.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 4","pages":"Pages 293-327"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143307918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.tcrr.2024.08.001
Adolfo Quesada-Román , Hugo G. Hidalgo , Eric J. Alfaro
Tropical cyclones (TC) pose a persistent natural hazard to Costa Rica. Exposure to natural hazards, such as mass movements and floods, is compounded by a growing urban population and inadequate land use planning. This study conducted a comprehensive analysis of the economic impacts of TC of Costa Rica from Hurricane Joan in 1988 to Hurricane Eta in 2020, assessing the impact by municipality and economic sector using baseline information of the Ministry of National Planning and Economic Policy. According to the study, road infrastructure (933.8 US million), agriculture (280.5 US million), river rehabilitation (153.96 US million), housing 98.26 (US million), and health (81.74 US million) were among the sectors most severely affected by TC over the past 30 years. The Pacific basin municipalities in Costa Rica were found to be the most vulnerable, primarily due to the indirect impacts of TC. The study's results offer useful information on the economic sectors and municipalities that are most exposed from TC in Costa Rica and provide a replicable methodology for other regions and countries facing similar tropical phenomena.
{"title":"Assessing the impact of tropical cyclones on economic sectors in Costa Rica, Central America","authors":"Adolfo Quesada-Román , Hugo G. Hidalgo , Eric J. Alfaro","doi":"10.1016/j.tcrr.2024.08.001","DOIUrl":"10.1016/j.tcrr.2024.08.001","url":null,"abstract":"<div><div>Tropical cyclones (TC) pose a persistent natural hazard to Costa Rica. Exposure to natural hazards, such as mass movements and floods, is compounded by a growing urban population and inadequate land use planning. This study conducted a comprehensive analysis of the economic impacts of TC of Costa Rica from Hurricane Joan in 1988 to Hurricane Eta in 2020, assessing the impact by municipality and economic sector using baseline information of the Ministry of National Planning and Economic Policy. According to the study, road infrastructure (933.8 US million), agriculture (280.5 US million), river rehabilitation (153.96 US million), housing 98.26 (US million), and health (81.74 US million) were among the sectors most severely affected by TC over the past 30 years. The Pacific basin municipalities in Costa Rica were found to be the most vulnerable, primarily due to the indirect impacts of TC. The study's results offer useful information on the economic sectors and municipalities that are most exposed from TC in Costa Rica and provide a replicable methodology for other regions and countries facing similar tropical phenomena.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 3","pages":"Pages 196-207"},"PeriodicalIF":2.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.tcrr.2024.08.002
Gengjiao Ye , Pingzhi Fang , Hui Yu
Traditionally, an empirical speed-up factor was introduced to reflect the effects of nonflat terrain on near-surface wind speeds. In this paper, the resistance effects of nonflat terrain are considered by introducing the terrain drag coefficient in the parametric wind field model for tropical cyclones (TCs) with a theoretical method. Terrain effects on wind fields are investigated in complex areas along the coastal zone in China under TC conditions. The results show that the terrain drag coefficient is the function of the slope angle and is sensitive to the spatial resolution. After including the resistance effect of nonflat terrain, the TC intensities weaken overall during landfall, with a slight enhancement near the coastal zone. The wind speeds outside the radius of the maximum wind speed decrease, while the wind speeds within the radius of the maximum wind speed increase. Both the TC eye and the radius of maximum wind speed shrink, which is more obvious when the TC center is entirely over land. As a result, the location and magnitude of the maximum wind speed are affected by the nonflat terrain. The changed structure of the wind fields demonstrates the necessity of considering the effects of nonflat terrain in simulating the wind fields under TC conditions.
{"title":"A theoretical method to characterize the resistance effects of nonflat terrain on wind fields in a parametric wind field model for tropical cyclones","authors":"Gengjiao Ye , Pingzhi Fang , Hui Yu","doi":"10.1016/j.tcrr.2024.08.002","DOIUrl":"10.1016/j.tcrr.2024.08.002","url":null,"abstract":"<div><div>Traditionally, an empirical speed-up factor was introduced to reflect the effects of nonflat terrain on near-surface wind speeds. In this paper, the resistance effects of nonflat terrain are considered by introducing the terrain drag coefficient in the parametric wind field model for tropical cyclones (TCs) with a theoretical method. Terrain effects on wind fields are investigated in complex areas along the coastal zone in China under TC conditions. The results show that the terrain drag coefficient is the function of the slope angle and is sensitive to the spatial resolution. After including the resistance effect of nonflat terrain, the TC intensities weaken overall during landfall, with a slight enhancement near the coastal zone. The wind speeds outside the radius of the maximum wind speed decrease, while the wind speeds within the radius of the maximum wind speed increase. Both the TC eye and the radius of maximum wind speed shrink, which is more obvious when the TC center is entirely over land. As a result, the location and magnitude of the maximum wind speed are affected by the nonflat terrain. The changed structure of the wind fields demonstrates the necessity of considering the effects of nonflat terrain in simulating the wind fields under TC conditions.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 3","pages":"Pages 161-174"},"PeriodicalIF":2.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.tcrr.2024.08.006
Zhiming Feng , Chenfei Liao , Jinyu Zeng
Based on the ERA5 reanalysis data and the surface observations from automatic weather stations, a comparative analysis has been conducted to investigate the differences in heavy rainfall distributions caused by two landfalling tropical cyclones (TCs): LUPIT (2109) and LISA (9610). The two TCs have similar tracks, intensity and landing points, but show different asymmetric features in their rainstorm location relative to their tracks. The results indicate that the TC rainfall differences are mainly caused by different rainstorm formation mechanisms. The wind shear contributes most to the rainstorm of LISA, while land-sea contrast and topographical effect are the main factors of LUPIT rainstorm. Under the influence of strong environmental vertical wind shear and the weak cold air invasion from the west, the circulation center of LISA tilts westward with height, which cooperates with the low-level water vapor convergence and vertical ascending movement on the western side of the TC center to jointly cause the heavy rainstorm to the west of LISA center. In contrast, LUPIT has weak environmental vertical wind shear and no obvious structure tilting with height. Topographic effect plays a crucial role in causing the heavy rainstorm on the north of TC center. The southeasterly jet is blocked by the Taimu Mountain in the northeastern Fujian Province, and the strong ascending motion caused by the terrain-induced convergence appears to the north of LUPIT center. In addition, the moisture convergence is more pronounced in the north and weaker in the south. The intrusion of weak cold air from the east to the coastal areas of central-northern Fujian, and the moisture-convergence distribution, jointly cause the heavy rainstorm to the north of LUPIT.
基于ERA5再分析数据和自动气象站的地面观测资料，我们对两个登陆热带气旋（TC）造成的强降雨分布差异进行了对比分析：LUPIT (2109) 和 LISA (9610)。这两个热带气旋的路径、强度和登陆点相似，但其暴雨位置相对于其路径呈现出不同的不对称特征。结果表明，热带气旋降雨量的差异主要是由不同的暴雨形成机制造成的。风切变对 LISA 的暴雨贡献最大，而陆海对比和地形效应是 LUPIT 暴雨的主要因素。在强大的环境垂直风切变和西侧弱冷空气入侵的影响下，LISA 的环流中心随着高度的增加向西倾斜，与 TC 中心西侧的低层水汽辐合和垂直上升运动共同作用，导致 LISA 中心西侧的暴雨。相比之下，LUPIT的环境垂直风切变较弱，结构随高度的倾斜不明显。地形效应是造成TC中心北侧暴雨的关键因素。东南气流受福建省东北部太姥山阻挡，地形辐合引起的强烈上升运动出现在鲁北TC中心以北。此外，北部的水汽辐合更为明显，南部则较弱。东部弱冷空气侵入闽中北部沿海地区，加上水汽辐合分布，共同造成了鲁北地区的暴雨。
{"title":"Comparative analysis of heavy rainfall area between landfalling typhoon LUPIT (2109) and typhoon LISA (9610)","authors":"Zhiming Feng , Chenfei Liao , Jinyu Zeng","doi":"10.1016/j.tcrr.2024.08.006","DOIUrl":"10.1016/j.tcrr.2024.08.006","url":null,"abstract":"<div><div>Based on the ERA5 reanalysis data and the surface observations from automatic weather stations, a comparative analysis has been conducted to investigate the differences in heavy rainfall distributions caused by two landfalling tropical cyclones (TCs): LUPIT (2109) and LISA (9610). The two TCs have similar tracks, intensity and landing points, but show different asymmetric features in their rainstorm location relative to their tracks. The results indicate that the TC rainfall differences are mainly caused by different rainstorm formation mechanisms. The wind shear contributes most to the rainstorm of LISA, while land-sea contrast and topographical effect are the main factors of LUPIT rainstorm. Under the influence of strong environmental vertical wind shear and the weak cold air invasion from the west, the circulation center of LISA tilts westward with height, which cooperates with the low-level water vapor convergence and vertical ascending movement on the western side of the TC center to jointly cause the heavy rainstorm to the west of LISA center. In contrast, LUPIT has weak environmental vertical wind shear and no obvious structure tilting with height. Topographic effect plays a crucial role in causing the heavy rainstorm on the north of TC center. The southeasterly jet is blocked by the Taimu Mountain in the northeastern Fujian Province, and the strong ascending motion caused by the terrain-induced convergence appears to the north of LUPIT center. In addition, the moisture convergence is more pronounced in the north and weaker in the south. The intrusion of weak cold air from the east to the coastal areas of central-northern Fujian, and the moisture-convergence distribution, jointly cause the heavy rainstorm to the north of LUPIT.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 3","pages":"Pages 175-186"},"PeriodicalIF":2.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.tcrr.2024.08.005
Pingzhi Fang , Tao Huo , Junjun Pan , Guihan Luan
Using high-frequency onshore wind data from four different heights of a coastal tower, the variations in gust factor with turbulence intensity, height and wind speed were studied under typhoon conditions. The gust factor increases with increasing turbulence intensity and, most often, can be described by a linear relationship with the turbulence intensity. The gust factor decreases with height and is relatively small compared with those presented in the national codes and other studies. A value of 2.5 is acceptable for the peak factor, which is close to the recommended value of the national code in China. The gust factor increases with increasing wind speed and is also affected by the wind direction. The gust factor has a value to that of previously published results when the wind flows roughly perpendicular to the shoreline, and has a smaller value when the wind flows roughly parallel to the shoreline. The phenomenon is caused by the confinement of shoreline on the sea wave development. Sea waves tend to propagate normal to the shoreline because of the refraction effect. As a result, a shorter roughness length exists in the parallel direction to the shoreline. It can be further explained by the weakness in the momentum flux exchange between the air and sea based on the wave form drag theory when the wind flows parallel to the shoreline.
{"title":"Variations in gust factor with wind direction and height based on the measurements from a coastal tower during three landfalling typhoons","authors":"Pingzhi Fang , Tao Huo , Junjun Pan , Guihan Luan","doi":"10.1016/j.tcrr.2024.08.005","DOIUrl":"10.1016/j.tcrr.2024.08.005","url":null,"abstract":"<div><div>Using high-frequency onshore wind data from four different heights of a coastal tower, the variations in gust factor with turbulence intensity, height and wind speed were studied under typhoon conditions. The gust factor increases with increasing turbulence intensity and, most often, can be described by a linear relationship with the turbulence intensity. The gust factor decreases with height and is relatively small compared with those presented in the national codes and other studies. A value of 2.5 is acceptable for the peak factor, which is close to the recommended value of the national code in China. The gust factor increases with increasing wind speed and is also affected by the wind direction. The gust factor has a value to that of previously published results when the wind flows roughly perpendicular to the shoreline, and has a smaller value when the wind flows roughly parallel to the shoreline. The phenomenon is caused by the confinement of shoreline on the sea wave development. Sea waves tend to propagate normal to the shoreline because of the refraction effect. As a result, a shorter roughness length exists in the parallel direction to the shoreline. It can be further explained by the weakness in the momentum flux exchange between the air and sea based on the wave form drag theory when the wind flows parallel to the shoreline.</div></div>","PeriodicalId":44442,"journal":{"name":"Tropical Cyclone Research and Review","volume":"13 3","pages":"Pages 187-195"},"PeriodicalIF":2.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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