2014年登陆广东省湛江市徐闻县的台风"海鸥"与"威马逊"均先在海南文昌翁田镇登陆后并穿过琼州海峡,台风路径相似。"威马逊"是1973年以来登陆华南的最强台风,中心气压910 h Pa,最大风力17级(60 m/s),"...2014年登陆广东省湛江市徐闻县的台风"海鸥"与"威马逊"均先在海南文昌翁田镇登陆后并穿过琼州海峡,台风路径相似。"威马逊"是1973年以来登陆华南的最强台风,中心气压910 h Pa,最大风力17级(60 m/s),"海鸥"中心气压960 h Pa,附近最大风力则为13级(40 m/s)。从台风强度来说,应该是"威马逊"增水比"海鸥"要大,然而事实却是"海鸥"实际出现的风暴增水远比"威马逊"严重。为更好地理解风暴潮机理及现象,有必要深入地分析造成这种差异现象的原因。展开更多
2014年9月16日夜间,第15号台风"海鸥"外围螺旋雨带中产生龙卷,袭击了广东省佛山市三水区白坭镇。通过现场灾情勘察、群众走访、新一代雷达观测等资料的综合分析,确定这次龙卷强度为EF1级。分析其发生发展的环境背景、雷达回...2014年9月16日夜间,第15号台风"海鸥"外围螺旋雨带中产生龙卷,袭击了广东省佛山市三水区白坭镇。通过现场灾情勘察、群众走访、新一代雷达观测等资料的综合分析,确定这次龙卷强度为EF1级。分析其发生发展的环境背景、雷达回波特征,并与相似台风路径下无龙卷产生的1409号超强台风"威马逊"环境条件对比,结果表明:龙卷发生在登陆台风"海鸥"移动方向的右后侧,对应上空200 h Pa为辐散区,500 h Pa为副热带高压和"海鸥"之间的强东南气流汇合处,从925 h Pa到500 h Pa强东南急流轴走向一致、上下叠加在珠江口附近,地面存在触发对流的东路弱冷空气和中尺度辐合线。环境条件呈弱的条件不稳定,对流有效位能(CAPE)小、抬升凝结高度(LCL)低、垂直风切变和风暴相对螺旋度(SRH)大;产生龙卷的对流风暴属于低质心的微型超级单体风暴,速度图上低层存在强中气旋,中气旋中心伴有TVS,中气旋和TVS尺度比较小、垂直伸展高度比较低,强中气旋、TVS分别早于龙卷14 min、8 min出现。龙卷出现在微型超级单体风暴右后侧钩状回波顶端、TVS附近。分析还表明,相似台风路径下,台风"海鸥"(有龙卷出现)和超强台风"威马逊"(无龙卷出现)的环境条件明显差异主要体现在0~1 km的低层垂直风切变和SRH上,后者的0~1 km垂直风切变和SRH均明显偏小,不利于微型超级单体风暴的出现。展开更多
The Sutong Bridge, a cable-stayed located in the southeast coastal area of China, is vulnerable to the Pacific typhoons. From the data measured by two 3D ultrasonic anemometers at the height of 76 m and 306 m, the win...The Sutong Bridge, a cable-stayed located in the southeast coastal area of China, is vulnerable to the Pacific typhoons. From the data measured by two 3D ultrasonic anemometers at the height of 76 m and 306 m, the wind characteristics （including 10-minute mean wind speed and direction, turbulence intensity and gust factor, power spectral density and integral scale of turbulence） of Typhoon Kalmaegi are analyzed The comparison of 10-minute mean wind velocity from the two anemometers vali- dates the reliability of wind data. The turbulence intensities （Iu, Iv, and Iw） show the decreasing trend as the mean wind speed increases. The mean value of Iv/Iu is 0.94, while that of Iw/Iu is 0.90. Discrepancy exists between field-measured power spectra and code-suggested spectra. Those results can enlarge the wind database of the southeast coastal area of China, and provide references for wind resistance evaluation of the bridge.展开更多
Kalmaegi(1415)required the issuance of Gale or Storm Wind Signal No.8 in Hong Kong in 2014,even though it passed by at a distance of 370 km from Hong Kong during its closest approach.Storm surges triggered by Kalmaegi...Kalmaegi(1415)required the issuance of Gale or Storm Wind Signal No.8 in Hong Kong in 2014,even though it passed by at a distance of 370 km from Hong Kong during its closest approach.Storm surges triggered by Kalmaegi caused backflow of sea water in some low lying areas in both Hong Kong and Macao.This paper reviews the use of observational data in monitoring the cyclone characteristics and studies the synoptic factors leading to its fast movement and extensive circulation.The combined analysis of multi-platform satellite wind retrieval,in-situ surface observations and aircraft reconnaissance data over the northern part of the South China Sea is found to be useful in depicting the cyclone structure.Synoptic analysis suggests that the relatively large size of Kalmaegi may be attributed to monsoon shear pattern during its formation stage and the subsequent strengthening of southwesterlies over the northern part of the South China Sea.A strong subtropical ridge north of Kalmaegi not only provides strong steering and thus its high translational speed,but also leads to extensive gale force wind distribution over its northern semi-circle.The performance of various numerical prediction models in forecasting the movement,intensity change and wind structure of Kalmaegi,as well as the storm surge triggered,is assessed and presented.展开更多
文摘2014年登陆广东省湛江市徐闻县的台风"海鸥"与"威马逊"均先在海南文昌翁田镇登陆后并穿过琼州海峡,台风路径相似。"威马逊"是1973年以来登陆华南的最强台风,中心气压910 h Pa,最大风力17级(60 m/s),"海鸥"中心气压960 h Pa,附近最大风力则为13级(40 m/s)。从台风强度来说,应该是"威马逊"增水比"海鸥"要大,然而事实却是"海鸥"实际出现的风暴增水远比"威马逊"严重。为更好地理解风暴潮机理及现象,有必要深入地分析造成这种差异现象的原因。
文摘2014年9月16日夜间,第15号台风"海鸥"外围螺旋雨带中产生龙卷,袭击了广东省佛山市三水区白坭镇。通过现场灾情勘察、群众走访、新一代雷达观测等资料的综合分析,确定这次龙卷强度为EF1级。分析其发生发展的环境背景、雷达回波特征,并与相似台风路径下无龙卷产生的1409号超强台风"威马逊"环境条件对比,结果表明:龙卷发生在登陆台风"海鸥"移动方向的右后侧,对应上空200 h Pa为辐散区,500 h Pa为副热带高压和"海鸥"之间的强东南气流汇合处,从925 h Pa到500 h Pa强东南急流轴走向一致、上下叠加在珠江口附近,地面存在触发对流的东路弱冷空气和中尺度辐合线。环境条件呈弱的条件不稳定,对流有效位能(CAPE)小、抬升凝结高度(LCL)低、垂直风切变和风暴相对螺旋度(SRH)大;产生龙卷的对流风暴属于低质心的微型超级单体风暴,速度图上低层存在强中气旋,中气旋中心伴有TVS,中气旋和TVS尺度比较小、垂直伸展高度比较低,强中气旋、TVS分别早于龙卷14 min、8 min出现。龙卷出现在微型超级单体风暴右后侧钩状回波顶端、TVS附近。分析还表明,相似台风路径下,台风"海鸥"(有龙卷出现)和超强台风"威马逊"(无龙卷出现)的环境条件明显差异主要体现在0~1 km的低层垂直风切变和SRH上,后者的0~1 km垂直风切变和SRH均明显偏小,不利于微型超级单体风暴的出现。
基金Supported by the Key Project of the National Natural Science Foundation of China (0538020)the National Natural Science Foundation of China for Distinguished Young Scientists (50725828)+1 种基金the National Natural Science Foundation of China (50908046)the Specialized Research Fund for the Doctoral Program of Higher Education (200802861012)
文摘The Sutong Bridge, a cable-stayed located in the southeast coastal area of China, is vulnerable to the Pacific typhoons. From the data measured by two 3D ultrasonic anemometers at the height of 76 m and 306 m, the wind characteristics （including 10-minute mean wind speed and direction, turbulence intensity and gust factor, power spectral density and integral scale of turbulence） of Typhoon Kalmaegi are analyzed The comparison of 10-minute mean wind velocity from the two anemometers vali- dates the reliability of wind data. The turbulence intensities （Iu, Iv, and Iw） show the decreasing trend as the mean wind speed increases. The mean value of Iv/Iu is 0.94, while that of Iw/Iu is 0.90. Discrepancy exists between field-measured power spectra and code-suggested spectra. Those results can enlarge the wind database of the southeast coastal area of China, and provide references for wind resistance evaluation of the bridge.
文摘Kalmaegi(1415)required the issuance of Gale or Storm Wind Signal No.8 in Hong Kong in 2014,even though it passed by at a distance of 370 km from Hong Kong during its closest approach.Storm surges triggered by Kalmaegi caused backflow of sea water in some low lying areas in both Hong Kong and Macao.This paper reviews the use of observational data in monitoring the cyclone characteristics and studies the synoptic factors leading to its fast movement and extensive circulation.The combined analysis of multi-platform satellite wind retrieval,in-situ surface observations and aircraft reconnaissance data over the northern part of the South China Sea is found to be useful in depicting the cyclone structure.Synoptic analysis suggests that the relatively large size of Kalmaegi may be attributed to monsoon shear pattern during its formation stage and the subsequent strengthening of southwesterlies over the northern part of the South China Sea.A strong subtropical ridge north of Kalmaegi not only provides strong steering and thus its high translational speed,but also leads to extensive gale force wind distribution over its northern semi-circle.The performance of various numerical prediction models in forecasting the movement,intensity change and wind structure of Kalmaegi,as well as the storm surge triggered,is assessed and presented.
