By using regular meteorological data and Doppler radar data,causes for a hail storm over northern area of Dalian on Oct.13,2009 were analyzed from several aspects,including synoptic background,T-LnP charts and the cha...By using regular meteorological data and Doppler radar data,causes for a hail storm over northern area of Dalian on Oct.13,2009 were analyzed from several aspects,including synoptic background,T-LnP charts and the characteristics of radar reflectivity factor evolution.The results showed that the hail storm occurred in downstream of 500 hPa trough.The 500 hPa cold trough turned zonally and triggered the formation of shear line on lower level.Before the hail event,instability energy and moisture supply were observed.The shear line on lower level intensified the atmospheric instability,promoted the release of potential energy,caused the hail event.The cooperation of upper and lower level jet streams provided favorable dynamic condition for strong convection development.The Doppler radar analysis showed that strong convection was comprised of multiple convection cells,which demonstrated 'L' and 'V' shapes during mature stage,with peak intensity of 50-60 dBz.展开更多
A thunderstorm that produced severe wind, heavy rain and hail on 23 August 2001 in Beijing was studied by a three-dimensional cloud model including hail-bin microphysics. This model can provide important information f...A thunderstorm that produced severe wind, heavy rain and hail on 23 August 2001 in Beijing was studied by a three-dimensional cloud model including hail-bin microphysics. This model can provide important information for hail size at the surface, which is not available in hail parameterization cloud models. The results shows that the cloud model, using hail-bin microphysics, could reasonably reflect the storm＇s characteristics such as life cycle, rainfall distribution and the diameter of the hailstones and also can reproduce developing processes of downbursts, where they can then be compared with the observed features of the storm. The downburst formation mechanism was investigated based on the cloud microphysics of the simulated storm and it was found that the downburst was primarily produced by hail-loading and enhanced by cooling processes that were due to hail melting and rain evaporation. The loading and melting of hail played crucial roles in the formation of downbursts within the storm.展开更多
Through multi-source data analyses of regional automatic station data, wind profiling radar, lightning information, new-generation weather-radar echo data and conventional observations in Fujian Province, and others, ...Through multi-source data analyses of regional automatic station data, wind profiling radar, lightning information, new-generation weather-radar echo data and conventional observations in Fujian Province, and others, this paper finds out aspects to focus on for potential forecasts and the nowcasting of wide-range gale weathers with thunderstorms and hail weathers in west Fujian Province on April 26th, 2016. Thus providing a basis for future forecasting of such catastrophic meteorological activities. Results of analyses showed that being affected by the eastward moving of upper troughs and the eastward and southward moving of low-level vortex shears, cold air and warm air strongly intersected in west Fujian Province;noticeable cold and warm advection formed the temperature frontal-zone;and under the triggering of the ground convergence line, impetuses formed by the strong convergent uplift before the south troughs forcibly produced wide-range squall lines, hails and other strong convective weathers. The squall line was caused by baroclinic frontogenesis. Hails with a diameter of up to 3 cm happened in the prefrontal warm zone. Supercells were generated and developed in the 80 km hot low-pressure convergence zone before the squall line moved along the direction at about 25° to the right of the mean wind field of the environment, belonged to right-shifting hailstorms, were of characteristics representing the hook echo and were of characteristics that the strength of the echo was high. On the afternoon of 26th, on the ground, temperature and humidity strongly increased. Fujian was located in the warm zone in the south side of the inverted trough. The specific humidity at 850 hPa was higher than 12 g/kg. The positive temperature change lasted for 24 hours. In the inland, the ridge was warm, while the trough was cold. Strong vertical wind shears that reached 20 m/s at 925 - 500 hPa and others were beneficial environmental conditions for forming the process of strong convective weather of baroclinic frontogenesis for this time.展开更多
A rare large-scale hail process in Yantai and Weihai City in the autumn of 2021 was analyzed based on the surface meteorology,high-altitude observation and S-band radar detection data.The results showed that this proc...A rare large-scale hail process in Yantai and Weihai City in the autumn of 2021 was analyzed based on the surface meteorology,high-altitude observation and S-band radar detection data.The results showed that this process was influenced by shallow trough,and strong upper-level jet stream in the middle and upper levels guided the intrusion of mid-level cold air into the warm and humid environment at the lower level.The shear lines and trunk lines in the lower level also provided certain triggering conditions for uplift,brewing conditions suitable for the occurrence and development of strong convection.The vertical wind shear was unusually large,and vertical wind shear was up to 10 m/s at 0-1 km,20 m/s at 0-3 km,and 32 m/s at 0-6 km,which was conducive to the growth of the storm.In this process,isolated multi-cell thunderstorm was generated at the beginning,and then it developed and strengthened continuously,moving to the southeast.In the later stage,a convection cell was born at the boundary between Yantai and Weihai,and developed into supercell storm.The storm lasted for a long time,and continued to develop and strengthen as it moved eastward,affecting most areas of Weihai from northwest to southeast.In the development stage of the storm,the radar reflectivity factor had obvious characteristics of hook echo and three-body scatter spike,and there was echo overhang and other hail echo features in the middle layer.Weak mesocyclone appeared at a low elevation,and there was the potential for the occurrence of tornado.展开更多
文摘By using regular meteorological data and Doppler radar data,causes for a hail storm over northern area of Dalian on Oct.13,2009 were analyzed from several aspects,including synoptic background,T-LnP charts and the characteristics of radar reflectivity factor evolution.The results showed that the hail storm occurred in downstream of 500 hPa trough.The 500 hPa cold trough turned zonally and triggered the formation of shear line on lower level.Before the hail event,instability energy and moisture supply were observed.The shear line on lower level intensified the atmospheric instability,promoted the release of potential energy,caused the hail event.The cooperation of upper and lower level jet streams provided favorable dynamic condition for strong convection development.The Doppler radar analysis showed that strong convection was comprised of multiple convection cells,which demonstrated 'L' and 'V' shapes during mature stage,with peak intensity of 50-60 dBz.
基金This research was jointly sponsored by the National Natural Science Foundation of China （Grant Nos. 40575003 and 40333033） the Chinese Academy of Sciences Innovation Foundation （Grant No. KZCX3-SW-213 and KZCX3-SW-225）.
文摘A thunderstorm that produced severe wind, heavy rain and hail on 23 August 2001 in Beijing was studied by a three-dimensional cloud model including hail-bin microphysics. This model can provide important information for hail size at the surface, which is not available in hail parameterization cloud models. The results shows that the cloud model, using hail-bin microphysics, could reasonably reflect the storm＇s characteristics such as life cycle, rainfall distribution and the diameter of the hailstones and also can reproduce developing processes of downbursts, where they can then be compared with the observed features of the storm. The downburst formation mechanism was investigated based on the cloud microphysics of the simulated storm and it was found that the downburst was primarily produced by hail-loading and enhanced by cooling processes that were due to hail melting and rain evaporation. The loading and melting of hail played crucial roles in the formation of downbursts within the storm.
文摘Through multi-source data analyses of regional automatic station data, wind profiling radar, lightning information, new-generation weather-radar echo data and conventional observations in Fujian Province, and others, this paper finds out aspects to focus on for potential forecasts and the nowcasting of wide-range gale weathers with thunderstorms and hail weathers in west Fujian Province on April 26th, 2016. Thus providing a basis for future forecasting of such catastrophic meteorological activities. Results of analyses showed that being affected by the eastward moving of upper troughs and the eastward and southward moving of low-level vortex shears, cold air and warm air strongly intersected in west Fujian Province;noticeable cold and warm advection formed the temperature frontal-zone;and under the triggering of the ground convergence line, impetuses formed by the strong convergent uplift before the south troughs forcibly produced wide-range squall lines, hails and other strong convective weathers. The squall line was caused by baroclinic frontogenesis. Hails with a diameter of up to 3 cm happened in the prefrontal warm zone. Supercells were generated and developed in the 80 km hot low-pressure convergence zone before the squall line moved along the direction at about 25° to the right of the mean wind field of the environment, belonged to right-shifting hailstorms, were of characteristics representing the hook echo and were of characteristics that the strength of the echo was high. On the afternoon of 26th, on the ground, temperature and humidity strongly increased. Fujian was located in the warm zone in the south side of the inverted trough. The specific humidity at 850 hPa was higher than 12 g/kg. The positive temperature change lasted for 24 hours. In the inland, the ridge was warm, while the trough was cold. Strong vertical wind shears that reached 20 m/s at 925 - 500 hPa and others were beneficial environmental conditions for forming the process of strong convective weather of baroclinic frontogenesis for this time.
基金Supported by the Science and Technology Research Project of Shandong Meteorological Bureau(2022sdqxm11).
文摘A rare large-scale hail process in Yantai and Weihai City in the autumn of 2021 was analyzed based on the surface meteorology,high-altitude observation and S-band radar detection data.The results showed that this process was influenced by shallow trough,and strong upper-level jet stream in the middle and upper levels guided the intrusion of mid-level cold air into the warm and humid environment at the lower level.The shear lines and trunk lines in the lower level also provided certain triggering conditions for uplift,brewing conditions suitable for the occurrence and development of strong convection.The vertical wind shear was unusually large,and vertical wind shear was up to 10 m/s at 0-1 km,20 m/s at 0-3 km,and 32 m/s at 0-6 km,which was conducive to the growth of the storm.In this process,isolated multi-cell thunderstorm was generated at the beginning,and then it developed and strengthened continuously,moving to the southeast.In the later stage,a convection cell was born at the boundary between Yantai and Weihai,and developed into supercell storm.The storm lasted for a long time,and continued to develop and strengthen as it moved eastward,affecting most areas of Weihai from northwest to southeast.In the development stage of the storm,the radar reflectivity factor had obvious characteristics of hook echo and three-body scatter spike,and there was echo overhang and other hail echo features in the middle layer.Weak mesocyclone appeared at a low elevation,and there was the potential for the occurrence of tornado.
基金supported by the Basic Scientific Program of the Institute of Atmospheric Physics supporting the 14th Five-Year Plan[Grant No.7-224151]Youth Innovation Team of China Meteorological Administration[Grant No.CMA2023QN10]+4 种基金the National Natural Science Foundation of China[Grant Nos.42175010,41965010,U223321842275010]Beijing Municipal Science and Technology Commission[Grant No.Z221100005222012]the Department of Science and Technology of Hebei Province[Grant No.22375404D]the Open subjects of the Key Open Laboratory of Cloud Physical Environment,China Meteorological Administration[Grant No.2020Z00715]。
文摘利用多普勒雷达资料,结合探空和常规资料,对2 0 1 1年4月1 7日一次超级单体雹暴的流场和回波结构演变特征进行了详细研究,主要结果:该雹暴是在条件性不稳定和垂直风切变较大的环境条件下产生的右移风暴。雹云初生发展阶段,垂直剖面显示逐渐形成有组织化的斜上升气流促进雹云发展。成熟降雹阶段,雹云内形成一支强的斜上升气流和深厚的中气旋,主上升气流对应雹云的弱回波区。雹云维持典型的弱回波区—悬挂回波—回波墙特征结构。根据雷达径向速度和雹云移速订正得出的"零线"演变发现,随着雹云的发展,"零线"逐渐向悬挂回波靠近,并穿过悬挂回波,"零线"的走向为上翘式,附近"穴道"的汇集力较强,有利于降雹。通过对"零线"位置的判断可分析有利成雹的区域。根据高低空两层强回波的水平错位,利用两高度强中心连线所作剖面能快速准确得出特征剖面,并将0°C层以上6 k m高度处降雹潜势达到1 0 0%的4 5 d B Z的区域识别为成雹区,与降雹实况对比发现识别效果良好。
