Pub Date : 2025-03-01DOI: 10.1016/j.aosl.2024.100555
Qiushi Wen , Xuefen Zhang , Sheng Hu , Peitao Zhao , Shuixin Zhong , Zhenyu Liu , Zhongkuo Zhao , Jiahao Liang , Guangfeng Dai , Chenzhong Zhang , Mengjie Li , Ling Huang
Based on the China Meteorological Administration's Tropical Regional Atmosphere Model for the South China Sea (CMA-TRAMS), the authors conducted a collaborative assimilation forecasting experiment utilizing both Beidou radiosonde and drone-dropped (HAIYAN-I) radiosonde data in September 2023. Three assimilation experimental groups were designed as follows: Beidou radiosonde assimilation, drone-dropped radiosonde assimilation, and collaborative assimilation of Beidou and drone-dropped radiosonde data (hereinafter referred to as “Beidou-drop”). Additionally, a control group of operational forecasts without these data assimilations was set up. The results indicate that the operational forecast path in the control group deviated northward from the actual path. Besides, the Beidou-drop group showed the most significant improvement in terms of forecasting the typhoon path at 60 to 90 h lead times. Specifically, the 72 h and 90 h path errors were reduced by 66.8 and 82.4 km, respectively, resulting in a much more accurate forecast of Typhoon Haikui's landing point, at the coastal junction of Fujian and Guangdong. Furthermore, the collaborative assimilation revealed a notable impact on improving the forecast of wind and rain associated with Haikui's landfall, aligning more closely with the real case. A marked rise was also seen in the precipitation score of the Beidou-drop group, where the 50 mm TS (threat score) of the 72 h lead time increased from 0.33 in the control experiment to 0.75, and the 100 mm TS rose from 0.18 to 0.39.
{"title":"Collaborative assimilation experiment of Beidou radiosonde and drone-dropped radiosonde based on CMA-TRAMS","authors":"Qiushi Wen , Xuefen Zhang , Sheng Hu , Peitao Zhao , Shuixin Zhong , Zhenyu Liu , Zhongkuo Zhao , Jiahao Liang , Guangfeng Dai , Chenzhong Zhang , Mengjie Li , Ling Huang","doi":"10.1016/j.aosl.2024.100555","DOIUrl":"10.1016/j.aosl.2024.100555","url":null,"abstract":"<div><div>Based on the China Meteorological Administration's Tropical Regional Atmosphere Model for the South China Sea (CMA-TRAMS), the authors conducted a collaborative assimilation forecasting experiment utilizing both Beidou radiosonde and drone-dropped (HAIYAN-I) radiosonde data in September 2023. Three assimilation experimental groups were designed as follows: Beidou radiosonde assimilation, drone-dropped radiosonde assimilation, and collaborative assimilation of Beidou and drone-dropped radiosonde data (hereinafter referred to as “Beidou-drop”). Additionally, a control group of operational forecasts without these data assimilations was set up. The results indicate that the operational forecast path in the control group deviated northward from the actual path. Besides, the Beidou-drop group showed the most significant improvement in terms of forecasting the typhoon path at 60 to 90 h lead times. Specifically, the 72 h and 90 h path errors were reduced by 66.8 and 82.4 km, respectively, resulting in a much more accurate forecast of Typhoon Haikui's landing point, at the coastal junction of Fujian and Guangdong. Furthermore, the collaborative assimilation revealed a notable impact on improving the forecast of wind and rain associated with Haikui's landfall, aligning more closely with the real case. A marked rise was also seen in the precipitation score of the Beidou-drop group, where the 50 mm TS (threat score) of the 72 h lead time increased from 0.33 in the control experiment to 0.75, and the 100 mm TS rose from 0.18 to 0.39.</div><div>摘要</div><div>基于中国气象局南海台风模式CMA-TRAMS, 开展了北斗探空和无人机下投探空协同同化预报试验, 分别开展了北斗探空同化, 无人机下投探空同化, 北斗和下投探空 (beidou-drop) 协同同化试验. 结果表明, CMA-TRAMS业务预报路径较实况偏北, 协同同化了北斗和下投探空的路径预报改进效果最显著, 对60–90小时路径预报均有改进, 72小时和90小时路径误差分别较减小66.8 km和82.4 km, 且台风海葵的登陆区域更趋于向实况 (闽粤沿海交界处); 协同同化了北斗和下投探空对台风“海葵”登陆风雨影响更为显著, 与实况更加吻合, 降水评分提升明显, 72小时预报的50 mm TS评分由对照试验的0.33提高至0.75; 100 mm降水TS评分由对照试验的0.18提高至0.39.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100555"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643301","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 : 2025-03-01DOI: 10.1016/j.aosl.2025.100608
Lili Lei , Jianfang Fei , Wen Zhou
{"title":"Theory and prediction of tropical cyclones and induced precipitation","authors":"Lili Lei , Jianfang Fei , Wen Zhou","doi":"10.1016/j.aosl.2025.100608","DOIUrl":"10.1016/j.aosl.2025.100608","url":null,"abstract":"","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100608"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643422","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 : 2025-03-01DOI: 10.1016/j.aosl.2025.100594
Zhuoying Li , Wen Zhou
Against the backdrop of climate change, the activity of tropical cyclones (TCs) has captured widespread attention. Observational datasets indicate a declining trend in the genesis longitude of western North Pacific (WNP) TCs. This study investigates the zonal changes of WNP TCs with CMIP6-HighResMIP models. These models capture the genesis density of WNP TCs fairly well. The results reveal a westward shift in TC genesis longitude. This trend is associated with the significant reduction in the TC frequency over the southeastern WNP. The study also discusses changes in large-scale circulation patterns and the impact of the strengthening Pacific Walker circulation.
Against the backdrop of climate change, the activity of tropical cyclones (TCs) has captured widespread attention. Observational datasets indicate a declining trend in the genesis longitude of western North Pacific (WNP) TCs. This study investigates the zonal changes of WNP TCs with CMIP6-HighResMIP models. These models capture the genesis density of WNP TCs fairly well. The results reveal a westward shift in TC genesis longitude. This trend is associated with the significant reduction in the TC frequency over the southeastern WNP. The study also discusses changes in large-scale circulation patterns and the impact of the strengthening Pacific Walker circulation.摘要在全球变暖背景下, 热带气旋的活动变化引起广泛关注. 观测数据表明, 西北太平洋热带气旋年平均生成经度呈减小趋势. 本研究利用CMIP6-HighResMIP模式对西北太平洋热带气旋活动的经度变化进行研究, 这些高分辨率模式较好地捕捉了西北太平洋热带气旋的生成密度. 研究显示西北太平洋地区热带气旋生成经度呈现西移的趋势, 这一趋势与西北太平洋地区东南部热带气旋频率的显著减少有关. 本研究还讨论了大尺度环流模式的变化以及太平洋沃克环流的加强所造成的影响.
{"title":"Westward shift of western North Pacific tropical cyclones in CMIP6-HighResMIP models","authors":"Zhuoying Li , Wen Zhou","doi":"10.1016/j.aosl.2025.100594","DOIUrl":"10.1016/j.aosl.2025.100594","url":null,"abstract":"<div><div>Against the backdrop of climate change, the activity of tropical cyclones (TCs) has captured widespread attention. Observational datasets indicate a declining trend in the genesis longitude of western North Pacific (WNP) TCs. This study investigates the zonal changes of WNP TCs with CMIP6-HighResMIP models. These models capture the genesis density of WNP TCs fairly well. The results reveal a westward shift in TC genesis longitude. This trend is associated with the significant reduction in the TC frequency over the southeastern WNP. The study also discusses changes in large-scale circulation patterns and the impact of the strengthening Pacific Walker circulation.</div><div>摘要</div><div>在全球变暖背景下, 热带气旋的活动变化引起广泛关注. 观测数据表明, 西北太平洋热带气旋年平均生成经度呈减小趋势. 本研究利用CMIP6-HighResMIP模式对西北太平洋热带气旋活动的经度变化进行研究, 这些高分辨率模式较好地捕捉了西北太平洋热带气旋的生成密度. 研究显示西北太平洋地区热带气旋生成经度呈现西移的趋势, 这一趋势与西北太平洋地区东南部热带气旋频率的显著减少有关. 本研究还讨论了大尺度环流模式的变化以及太平洋沃克环流的加强所造成的影响.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100594"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643432","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 : 2025-03-01DOI: 10.1016/j.aosl.2024.100479
Yidan Lin , Kekuan Chu , Zhe-Min Tan
This study employs the self-organizing map method to investigate the upper-tropospheric outflow patterns of tropical cyclones (TCs) over the western North Pacific from 1979 to 2019, using the 200 hPa horizontal wind fields from the ERA5 reanalysis datasets. According to the number and orientation of TC outflow channels, as well as the wind speed, the outflow patterns are classified into five categories: southwestward single-channel pattern S1 (26.1%); northwestward single-channel pattern S2 (23.6%); northeastward single-channel pattern S3 (23.6%); double-channel outflow pattern D (20.8%); and high latitude outflow pattern H (6.0%). Composite analysis shows that the orientations of the TC outflow channels are aligned with the direction of the environmental vertical wind shear and closely related to the distribution of the environmental inertial instability, upper-level divergence, and inner-core convective activities. TC intensity and intensity changes for different outflow patterns are also significantly different. Patterns S1 and S2 usually appear in the development phase and are thus prone to TC intensification, while patterns S3 and H usually occur in the weakening phase and are thus prone to TC weakening. The double-channel pattern (D) has the largest mean intensity and accounts for more than 60% of super-typhoon samples.
{"title":"Characteristics of tropical cyclone outflow over the western North Pacific","authors":"Yidan Lin , Kekuan Chu , Zhe-Min Tan","doi":"10.1016/j.aosl.2024.100479","DOIUrl":"10.1016/j.aosl.2024.100479","url":null,"abstract":"<div><div>This study employs the self-organizing map method to investigate the upper-tropospheric outflow patterns of tropical cyclones (TCs) over the western North Pacific from 1979 to 2019, using the 200 hPa horizontal wind fields from the ERA5 reanalysis datasets. According to the number and orientation of TC outflow channels, as well as the wind speed, the outflow patterns are classified into five categories: southwestward single-channel pattern S1 (26.1%); northwestward single-channel pattern S2 (23.6%); northeastward single-channel pattern S3 (23.6%); double-channel outflow pattern D (20.8%); and high latitude outflow pattern H (6.0%). Composite analysis shows that the orientations of the TC outflow channels are aligned with the direction of the environmental vertical wind shear and closely related to the distribution of the environmental inertial instability, upper-level divergence, and inner-core convective activities. TC intensity and intensity changes for different outflow patterns are also significantly different. Patterns S1 and S2 usually appear in the development phase and are thus prone to TC intensification, while patterns S3 and H usually occur in the weakening phase and are thus prone to TC weakening. The double-channel pattern (D) has the largest mean intensity and accounts for more than 60% of super-typhoon samples.</div><div>摘要</div><div>本文基于欧洲中期天气预报中心第五代大气再分析数据集 (ERA5) 的200 hPa水平风场数据, 借助自组织映射网络方法对1979–2019年间西北太平洋热带气旋的流出层特征进行了客观分型研究. 根据流出通道的数量, 方向以及风速大小等特征, 西北太平洋热带气旋流出层主要可分为五种流出类型: 西南向单流出通道型 (26.1%); 西北向单出流通道型 (23.6%); 东北向单流出通道型 (23.6%), 双流出通道型 (20.8%) 以及高纬度流出通道型 (6.0%). 不同流出通道类型对应的热带气旋高层热力, 动力结构具有显著差异, 流出通道的方向与高层惯性稳定度, 散度场, 以及热带气旋内核区对流活动的分布等密切相关. 同时, 流出通道类型与热带气旋的强度及强度变化也具有密切联系. 西南和西北向单通道流出型主要发生在增强阶段, 具有东北向单流出通道和高纬流出通道的热带气旋则更倾向于衰减. 双流出通道型的热带气旋样本具有最大的平均强度, 且热带气旋强度越强, 双流出通道出现的频率越大, 占强热带气旋样本的60%以上.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100479"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139892492","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 : 2025-03-01DOI: 10.1016/j.aosl.2025.100589
Junjie Deng , Jin Zhang , Haoyan Liu , Hongqi Li , Feng Chen , Jing Chen
The impacts of lateral boundary conditions (LBCs) provided by numerical models and data-driven networks on convective-scale ensemble forecasts are investigated in this study. Four experiments are conducted on the Hangzhou RDP (19th Hangzhou Asian Games Research Development Project on Convective-scale Ensemble Prediction and Application) testbed, with the LBCs respectively sourced from National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) forecasts with 33 vertical levels (Exp_GFS), Pangu forecasts with 13 vertical levels (Exp_Pangu), Fuxi forecasts with 13 vertical levels (Exp_Fuxi), and NCEP GFS forecasts with the vertical levels reduced to 13 (the same as those of Exp_Pangu and Exp_Fuxi) (Exp_GFSRDV). In general, Exp_Pangu performs comparably to Exp_GFS, while Exp_Fuxi shows slightly inferior performance compared to Exp_Pangu, possibly due to its less accurate large-scale predictions. Therefore, the ability of using data-driven networks to efficiently provide LBCs for convective-scale ensemble forecasts has been demonstrated. Moreover, Exp_GFSRDV has the worst convective-scale forecasts among the four experiments, which indicates the potential improvement of using data-driven networks for LBCs by increasing the vertical levels of the networks. However, the ensemble spread of the four experiments barely increases with lead time. Thus, each experiment has insufficient ensemble spread to present realistic forecast uncertainties, which will be investigated in a future study.
{"title":"Impacts of lateral boundary conditions from numerical models and data-driven networks on convective-scale ensemble forecasts","authors":"Junjie Deng , Jin Zhang , Haoyan Liu , Hongqi Li , Feng Chen , Jing Chen","doi":"10.1016/j.aosl.2025.100589","DOIUrl":"10.1016/j.aosl.2025.100589","url":null,"abstract":"<div><div>The impacts of lateral boundary conditions (LBCs) provided by numerical models and data-driven networks on convective-scale ensemble forecasts are investigated in this study. Four experiments are conducted on the Hangzhou RDP (19th Hangzhou Asian Games Research Development Project on Convective-scale Ensemble Prediction and Application) testbed, with the LBCs respectively sourced from National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) forecasts with 33 vertical levels (Exp_GFS), Pangu forecasts with 13 vertical levels (Exp_Pangu), Fuxi forecasts with 13 vertical levels (Exp_Fuxi), and NCEP GFS forecasts with the vertical levels reduced to 13 (the same as those of Exp_Pangu and Exp_Fuxi) (Exp_GFSRDV). In general, Exp_Pangu performs comparably to Exp_GFS, while Exp_Fuxi shows slightly inferior performance compared to Exp_Pangu, possibly due to its less accurate large-scale predictions. Therefore, the ability of using data-driven networks to efficiently provide LBCs for convective-scale ensemble forecasts has been demonstrated. Moreover, Exp_GFSRDV has the worst convective-scale forecasts among the four experiments, which indicates the potential improvement of using data-driven networks for LBCs by increasing the vertical levels of the networks. However, the ensemble spread of the four experiments barely increases with lead time. Thus, each experiment has insufficient ensemble spread to present realistic forecast uncertainties, which will be investigated in a future study.</div><div>摘要</div><div>本文探讨了基于人工智能大模型的边界条件对对流尺度集合预报的影响. 四组实验的边界条件分别来自美国国家环境预报中心 (NCEP) 全球预报系统 (GFS) 的33层预报 (Exp_GFS) , 13层预报 (Exp_GFSRDV) , 盘古 (Pangu) 的预报 (Exp_Pangu) 和伏羲 (Fuxi) 的预报 (Exp_Fuxi) . 结果表明, Exp_Pangu的预报表现与Exp_GFS相当, 而Exp_Fuxi的预报表现略逊于Exp_Pangu, 这可能是因为盘古的预报在大尺度上比伏羲更准确, 因此人工智能大模型能有效地为对流尺度集合预报提供边界条件. 此外, 在四组实验中, Exp_GFSRDV的预报结果最差, 这表明通过增加神经网络的垂直层数, 有潜力进一步改进使用人工智能大模型提供边界条件的预报结果. 然而, 四组实验的集合离散度几乎不会随着预报时长的增加而变大, 因此其集合离散度不足以表征预报的不确定性, 这点将在后续进一步研究.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100589"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643362","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 : 2025-03-01DOI: 10.1016/j.aosl.2024.100552
Yixuan Ren, Lili Lei, Jian-Feng Gu, Zhe-Min Tan, Yi Zhang
While steady improvements have been achieved for the track forecasts of typhoons, there has been a lack of improvement for intensity forecasts. One challenge for intensity forecasts is to capture the rapid intensification (RI), whose nonlinear characteristics impose great difficulties for numerical models. The ensemble sensitivity analysis (ESA) method is used here to analyze the initial conditions that contribute to typhoon intensity forecasts, especially with RI. Six RI processes from five typhoons (Chaba, Haima, Meranti, Sarika, and Songda) in 2016, are applied with ESA, which also gives a composite initial condition that favors subsequent RI. Results from individual cases have generally similar patterns of ESA, but with different magnitudes, when various cumulus parameterization schemes are applied. To draw the initial conditions with statistical significance, sample-mean azimuthal components of ESA are obtained. Results of the composite sensitivity show that typhoons that experience RI in 24 h favor enhanced primary circulation from low to high levels, intensified secondary circulation with increased radial inflow at lower levels and increased radial outflow at upper levels, a prominent warm core at around 300 hPa, and increased humidity at low levels. As the forecast lead time increases, the patterns of ESA are retained, while the sensitivity magnitudes decay. Given the general and quantitative composite sensitivity along with associated uncertainties for different cumulus parameterization schemes, appropriate sampling of the composite sensitivity in numerical models could be beneficial to capturing the RI and improving the forecasting of typhoon intensity.
{"title":"Understanding the initial conditions contributing to the rapid intensification of typhoons through ensemble sensitivity analysis","authors":"Yixuan Ren, Lili Lei, Jian-Feng Gu, Zhe-Min Tan, Yi Zhang","doi":"10.1016/j.aosl.2024.100552","DOIUrl":"10.1016/j.aosl.2024.100552","url":null,"abstract":"<div><div>While steady improvements have been achieved for the track forecasts of typhoons, there has been a lack of improvement for intensity forecasts. One challenge for intensity forecasts is to capture the rapid intensification (RI), whose nonlinear characteristics impose great difficulties for numerical models. The ensemble sensitivity analysis (ESA) method is used here to analyze the initial conditions that contribute to typhoon intensity forecasts, especially with RI. Six RI processes from five typhoons (Chaba, Haima, Meranti, Sarika, and Songda) in 2016, are applied with ESA, which also gives a composite initial condition that favors subsequent RI. Results from individual cases have generally similar patterns of ESA, but with different magnitudes, when various cumulus parameterization schemes are applied. To draw the initial conditions with statistical significance, sample-mean azimuthal components of ESA are obtained. Results of the composite sensitivity show that typhoons that experience RI in 24 h favor enhanced primary circulation from low to high levels, intensified secondary circulation with increased radial inflow at lower levels and increased radial outflow at upper levels, a prominent warm core at around 300 hPa, and increased humidity at low levels. As the forecast lead time increases, the patterns of ESA are retained, while the sensitivity magnitudes decay. Given the general and quantitative composite sensitivity along with associated uncertainties for different cumulus parameterization schemes, appropriate sampling of the composite sensitivity in numerical models could be beneficial to capturing the RI and improving the forecasting of typhoon intensity.</div><div>摘要</div><div>针对台风强度特别是快速增强 (RI) 的预报难点, 本文对2016年5个台风的6次RI过程应用集合敏感性分析 (ESA), 以分析有利于RI的初始条件. 对于不同的个例和积云参数化方案, ESA获得的有利于台风RI的集合敏感性相似但量级存在差异. 复合敏感性揭示了经历RI的台风所需的初始条件, 其有更强的主环流, 更显著的暖心及增加的低层湿度. ESA估计的集合敏感性随预报时长增加而减弱. 通过采样复合敏感性可有望改进集合初始条件及台风强度预报.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100552"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643423","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 : 2025-03-01DOI: 10.1016/j.aosl.2024.100465
Yixuan He , Qingqing Li , Yufan Dai
This study investigates the characteristics of secondary eyewall formation (SEF) in idealized tropical cyclones embedded in vertical wind shear (VWS) at different heights. The results show that upper-layer VWS at a relatively low shear height is more favorable for SEF than upper-layer VWS at a relatively high shear height and lower-layer VWS. In the experiments with upper-layer VWS at a relatively low shear height, better-organized stratiform clouds are located in the downwind sector of outer rainbands. The low-level descending inflow associated with the stratiform sector is stronger in these experiments than in the experiments with upper-layer VWS at a relatively high shear height and lower-layer VWS. The enhanced descending inflow can trigger supergradient winds and convergence near the top of the boundary layer, close to three times the radius of the maximum wind, where convection is locally forced. The subsequent convection axisymmetrization leads to SEF.
{"title":"Secondary eyewall formation in upper- and lower-layer vertical wind shear simulated in idealized tropical cyclones","authors":"Yixuan He , Qingqing Li , Yufan Dai","doi":"10.1016/j.aosl.2024.100465","DOIUrl":"10.1016/j.aosl.2024.100465","url":null,"abstract":"<div><div>This study investigates the characteristics of secondary eyewall formation (SEF) in idealized tropical cyclones embedded in vertical wind shear (VWS) at different heights. The results show that upper-layer VWS at a relatively low shear height is more favorable for SEF than upper-layer VWS at a relatively high shear height and lower-layer VWS. In the experiments with upper-layer VWS at a relatively low shear height, better-organized stratiform clouds are located in the downwind sector of outer rainbands. The low-level descending inflow associated with the stratiform sector is stronger in these experiments than in the experiments with upper-layer VWS at a relatively high shear height and lower-layer VWS. The enhanced descending inflow can trigger supergradient winds and convergence near the top of the boundary layer, close to three times the radius of the maximum wind, where convection is locally forced. The subsequent convection axisymmetrization leads to SEF.</div><div>摘要</div><div>不同高度垂直风切变下热带气旋外眼墙形成特征存在明显差异. 研究发现较低的高层切变比较高的高层切变和低层切变更有利于外眼墙形成. 结果表明, 较低的高层切变环境下外雨带下游的层云更具组织化, 与层云相关的下沉入流更强, 有利于在边界层上方三倍最大风半径附近产生更强的超梯度风和辐合, 有利于强迫出对流以及之后的轴对称化过程最终形成外眼墙.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100465"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139633965","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 : 2025-03-01DOI: 10.1016/j.aosl.2024.100573
Jiancheng Huang, Zhanhong Ma, Lei Liu, Xiangcheng Li, Tianli Jiang
Tropical cyclone–induced heavy precipitation (TCP) can have a detrimental impact on human productivity, causing significant economic losses and even human casualties in coastal countries every year. In this review article, the authors highlight the latest research developments in terms of ocean–atmosphere interactions and TCP, and identify the gaps where further research is required to enhance our understanding. The paper revolves around the following topics: (1) the characteristics of TCP over the ocean; (2) how air–sea interface processes, including sea surface temperature, sea-salt aerosols, and sea spray, influence TCP development; (3) the effects of TCP on the ocean; and (4) TCP changes in the context of global warming. In addition, directions and suggestions for future research toward a more comprehensive understanding of TCP–ocean interactions are discussed. Overall, this review summarizes the recent research progress and challenges in TCP–ocean interactions, and could serve as a guide for improvements in convective parameterization schemes and climate models toward predicting TCP distribution and intensity more accurately.
{"title":"Perspectives and challenges on the interaction between tropical cyclone precipitation and the ocean: A review","authors":"Jiancheng Huang, Zhanhong Ma, Lei Liu, Xiangcheng Li, Tianli Jiang","doi":"10.1016/j.aosl.2024.100573","DOIUrl":"10.1016/j.aosl.2024.100573","url":null,"abstract":"<div><div>Tropical cyclone–induced heavy precipitation (TCP) can have a detrimental impact on human productivity, causing significant economic losses and even human casualties in coastal countries every year. In this review article, the authors highlight the latest research developments in terms of ocean–atmosphere interactions and TCP, and identify the gaps where further research is required to enhance our understanding. The paper revolves around the following topics: (1) the characteristics of TCP over the ocean; (2) how air–sea interface processes, including sea surface temperature, sea-salt aerosols, and sea spray, influence TCP development; (3) the effects of TCP on the ocean; and (4) TCP changes in the context of global warming. In addition, directions and suggestions for future research toward a more comprehensive understanding of TCP–ocean interactions are discussed. Overall, this review summarizes the recent research progress and challenges in TCP–ocean interactions, and could serve as a guide for improvements in convective parameterization schemes and climate models toward predicting TCP distribution and intensity more accurately.</div><div>摘要</div><div>热带气旋引起的强降水 (TCP) 经常对人类生产生活产生不利影响, 每年给沿海国家造成重大经济损失和人员伤亡. 本综述重点梳理回顾了海气相互作用和热带气旋降水方面近年来的研究进展, 并指出了有待进一步研究的差距领域, 以增强对热带气旋降水的认识. 本文主要围绕以下主题展开: (1) 海洋上的TCP特征; (2) 海气界面过程 (海表面温度, 海盐气溶胶和海雾等) 如何影响TCP的发展; (3) TCP对海洋的影响; (4) 全球变暖背景下的TCP变化. 此外, 文章提出了结论性的方向和建议, 以期对TCP与海洋的相互作用有更全面的认识. 总体而言, 本文总结了近年来TCP与海洋相互作用的最新研究进展和面临的挑战, 可指导改进对流参数化方案和气候模型, 以更准确地预测TCP的分布和强度.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100573"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643360","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 : 2025-03-01DOI: 10.1016/j.aosl.2024.100557
Ling Huang , Chunxia Liu , Yongqiang Yu , Liwei Zou
This paper provides a comparative analysis of the performance of a high-resolution regional ocean–atmosphere coupled model in predicting tropical cyclone (TC) gales over the northern South China Sea. The atmosphere and ocean components of the coupled system are represented by the China Meteorological Administration's Tropical Regional Atmosphere Model for the South China Sea (CMA-TRAMS) and the LASG/IAP Climate system Ocean Model (LICOM), respectively. The Ocean Atmosphere Sea Ice Soil VersionH 3 (OASIS3) software has been utilized for the exchange of momentum, heat, and freshwater fluxes between these two components. An assessment of the coupled model's three-day predictions for five TCs’ gales was conducted. Preliminary findings indicate that the predicted TC tracks show less sensitivity to oceanic influences than the predicted TC intensities. Significant improvement in predicting the surface TC gales has been achieved through coupling the ocean model. This improvement is attributed to the impact of the warmer ocean's effect on TC intensification, counteracting the cooling effect of the cold wake. In summary, coupling has enhanced the model's predictive capabilities for TC gales. A detailed assessment of the coupled model's performance in predicting other tropical weather phenomena is forthcoming.
{"title":"A regional ocean–atmosphere coupled model using CMA-TRAMS and LICOM: Preliminary results for tropical cyclone gale prediction over the northern South China Sea","authors":"Ling Huang , Chunxia Liu , Yongqiang Yu , Liwei Zou","doi":"10.1016/j.aosl.2024.100557","DOIUrl":"10.1016/j.aosl.2024.100557","url":null,"abstract":"<div><div>This paper provides a comparative analysis of the performance of a high-resolution regional ocean–atmosphere coupled model in predicting tropical cyclone (TC) gales over the northern South China Sea. The atmosphere and ocean components of the coupled system are represented by the China Meteorological Administration's Tropical Regional Atmosphere Model for the South China Sea (CMA-TRAMS) and the LASG/IAP Climate system Ocean Model (LICOM), respectively. The Ocean Atmosphere Sea Ice Soil VersionH 3 (OASIS3) software has been utilized for the exchange of momentum, heat, and freshwater fluxes between these two components. An assessment of the coupled model's three-day predictions for five TCs’ gales was conducted. Preliminary findings indicate that the predicted TC tracks show less sensitivity to oceanic influences than the predicted TC intensities. Significant improvement in predicting the surface TC gales has been achieved through coupling the ocean model. This improvement is attributed to the impact of the warmer ocean's effect on TC intensification, counteracting the cooling effect of the cold wake. In summary, coupling has enhanced the model's predictive capabilities for TC gales. A detailed assessment of the coupled model's performance in predicting other tropical weather phenomena is forthcoming.</div><div>摘要</div><div>本文对一个具有我国自主知识产权的高分辨率区域海气耦合模式在南海北部台风大风预报性能进行对比分析. 该耦合模式的大气和海洋部分分别为中国气象局南海台风模式 (CMA-TRAMS) 和中国科学院大气物理研究所的海洋模式 (LICOM), 并用OASIS耦合器实现海气界面动量, 热量和淡水通量的交换. 本文对海气耦合模式预报5个台风的24, 48和72小时大风的性能进行了检验评估. 初步结果表明, 预报的台风路径对海洋影响的敏感性低于台风强度. 耦合模式使预报台风大风的准确性得到显著提高, 这一改进归结于海气耦合模式更为准确的海表温度对台风增强的影响, 从而抵消了冷尾流的降温效应. 总而言之, 耦合模式增强了模式对台风大风的预报能力. 关于海气耦合模式在其他热带天气中的预报能力评估将在未来工作中展示.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100557"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643302","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 : 2025-03-01DOI: 10.1016/j.aosl.2024.100560
Tianju Wang , Ju Wang
The present study employs statistical analysis to investigate the relationship between the geopotential height anomalies induced by tropical cyclones (TCs) and the meridional movement of the western Pacific subtropical high (WPSH), as well as the mechanisms through which TCs can induce such geopotential height anomalies. Results show that TCs can cause the WPSH to move northward, and the meridional motion of the WPSH ridgeline is related with the geopotential height anomalies, which is better indicated by the relative geopotential height anomalies. In the process of TCs causing the WPSH to move northward, the TCs cause abnormal horizonal warm (cold) advection and abnormal ascending (descending) motion in the region south (north) of 40°N. Since the influence of the abnormal vertical motion is weaker, the abnormal temperature tendency eventually shows a more consistent phase distribution with the abnormal horizonal temperature advection, which is favorable for the temperature to abnormally increase near 40°N. Such an abnormal increase in temperature causes the geopotential height to abnormally increase under the static equilibrium constraint, which further changes the location of the centroid of the WPSH geopotential height, and hence the location of the WPSH ridgeline changes as well.
{"title":"Relationship between the geopotential height anomalies induced by tropical cyclones and the meridional movement of the western Pacific subtropical high","authors":"Tianju Wang , Ju Wang","doi":"10.1016/j.aosl.2024.100560","DOIUrl":"10.1016/j.aosl.2024.100560","url":null,"abstract":"<div><div>The present study employs statistical analysis to investigate the relationship between the geopotential height anomalies induced by tropical cyclones (TCs) and the meridional movement of the western Pacific subtropical high (WPSH), as well as the mechanisms through which TCs can induce such geopotential height anomalies. Results show that TCs can cause the WPSH to move northward, and the meridional motion of the WPSH ridgeline is related with the geopotential height anomalies, which is better indicated by the relative geopotential height anomalies. In the process of TCs causing the WPSH to move northward, the TCs cause abnormal horizonal warm (cold) advection and abnormal ascending (descending) motion in the region south (north) of 40°N. Since the influence of the abnormal vertical motion is weaker, the abnormal temperature tendency eventually shows a more consistent phase distribution with the abnormal horizonal temperature advection, which is favorable for the temperature to abnormally increase near 40°N. Such an abnormal increase in temperature causes the geopotential height to abnormally increase under the static equilibrium constraint, which further changes the location of the centroid of the WPSH geopotential height, and hence the location of the WPSH ridgeline changes as well.</div><div>摘要</div><div>本文采用统计分析方法, 讨论了热带气旋引起的位势高度异常与西太副高经向移动之间的关系, 并给出了可能机理. 研究表明, 热带气旋可导致西太副高向北移动, 这样的西太副高异常移动与相对位势高度异常的联系更加紧密. 其原因在于, 热带气旋在40°N附近引起了异常水平温度平流和异常垂直运动, 这对西太副高异常北移起到了重要作用. 但由于异常垂直运动的影响相对较弱, 使得异常温度倾向最终与异常水平温度平流更为一致, 导致40°N附近温度异常升高.这样温度异常升高在静力平衡约束下又导致位势高度异常升高, 最终使得西太副高的经向位置发生变化.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 2","pages":"Article 100560"},"PeriodicalIF":2.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643303","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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