In the present study, a severe squall line(SL) was analyzed by using intensive observational surface data and radar monitoring products. In this process, mesoscale convergence lines, such as the sea breeze front(SBF),...In the present study, a severe squall line(SL) was analyzed by using intensive observational surface data and radar monitoring products. In this process, mesoscale convergence lines, such as the sea breeze front(SBF), gust front and dry line, served as the main triggering and strengthening factors. The transition from convection triggering to the formation of the initial shape was mainly affected by the convergence line of the SBF, which combined with thermal convection to form the main parts of the SL. In the later stage, the convergence line of the gust front merged with other convergence lines to form a series of strong convective cells. The SBF had good indicative significance in terms of severe convective weather warnings. The suitable conditions of heat, water vapor and vertical wind shear on the Shandong Peninsula were beneficial to the maintenance of the SL. Before SL occurrence, tropopause folding strengthened, which consequently enhanced the baroclinic property in the middle and upper troposphere. The high sensible heat flux at the surface easily produced a positive potential vorticity anomaly in the low layer, resulting in convective instability, which was conducive to the maintenance of these processes. In the system, when precipitation particles passed through the unsaturated air layer, they underwent strong evaporation, melting or sublimation, and the cooling effect formed negative buoyancy, which accelerated the sinking of the air and promoted the sustained development of the surface gale. Together with the development of lowlevel mesocyclones, the air pressure decreased rapidly, which was conducive to gale initiation.展开更多
This work discusses issues related to the impact of urbanization on the microphysical processes of precipitating systems associated with synoptic, mesoscale, and local scale systems. Among the issues addressed is the ...This work discusses issues related to the impact of urbanization on the microphysical processes of precipitating systems associated with synoptic, mesoscale, and local scale systems. Among the issues addressed is the impact of urban heat <span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">island (UHI) in S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center and urban densification (UD) in the</span><span> </span><span style="font-family:Verdana;">Metropolitan Area of S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo (MASP) on the microphysical, dynamic, and</span><span style="font-family:Verdana;"> thermodynamic properties and distribution of precipitation and heavier rainfall from sea-breeze (SB) e cold-front (CF) combined during their space-time evolutions. For this purpose, it used four components: classification of hydrometeors with fuzzy logic, calculation of the raindrop diameters, an estimate of liquid water mass and ice mass from polarimetric-variables measured with dual-pola- rization X-band meteorological radar. The results indicated that urban densification (UD) and heat island (UHI) of the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center impact the formation of precipitation, liquid water mass, and ice mass, depth, and duration of </span><span style="font-family:Verdana;">a thunderstorm. It was also observed the asymmetric configuration of the th</span><span style="font-family:Verdana;">understorm is induced by the strong convergence in the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center, and this strong convergence is induced by the intense heat island (UHI) in the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center. Was also observed that this event that is formed in the Metropolitan Area of S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span>o Paulo (MASP) depends on microphysical processes of mixed-phase of the cloud (water and ice) above the 0<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span>C isotherm for the production of intense rain and cold pool at the surface. These important microphysical processes within long-lasting secondary convective cells over the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center should be taken into account on convective parameterization schemes as well as the associated cold pool dynamics.</span></span></span></span>展开更多
对2007年8月13日天津多普勒天气雷达(CIN RAD WSR/98D)探测的雷暴天气个例进行分析,结果表明:此次雷暴天气是由渤海湾海风锋与阵风锋碰撞形成的;碰撞后,在海风锋前端、阵风锋前部有新的雷暴单体形成;阵风锋后部的对流回波主体加强,...对2007年8月13日天津多普勒天气雷达(CIN RAD WSR/98D)探测的雷暴天气个例进行分析,结果表明:此次雷暴天气是由渤海湾海风锋与阵风锋碰撞形成的;碰撞后,在海风锋前端、阵风锋前部有新的雷暴单体形成;阵风锋后部的对流回波主体加强,对流回波主体由椭圆状加强为典型的弓状。应用天津36个自动气象站的地面六要素资料和北京850 h Pa以上探空资料,组成新的诊断资料,对该个例进行诊断分析,结果表明:雷达探测的海风锋前端具有较强的低层垂直风切变梯度和露点温度梯度大值区,海风锋前沿与0~3 km垂直风切变梯度密集区相对应,且与露点温度梯度变化较快的区域基本吻合;海风锋与阵风锋相互碰撞时,0~3 km垂直风切变在2 h内变化较快,且有明显的增加趋势,CAPE(convective available potential energy,对流有效位能)值在雷暴形成前有较明显增加;随着雷暴天气结束,上述特征随之消失。展开更多
基金Natural Science Foundation of Shandong Province (ZR2021MD062, ZR2021MD010, ZR2023MD118)National Natural Science Foundation of China (42275001)+2 种基金Shandong Meteorological Bureau Innovation Team Project (SDCXTD2023-1)Huaihe River Meteorology Open Research Fund (HRM201807)Key Special Project of Qingdao Meteorological Bureau (2023qdqxz02)。
文摘In the present study, a severe squall line(SL) was analyzed by using intensive observational surface data and radar monitoring products. In this process, mesoscale convergence lines, such as the sea breeze front(SBF), gust front and dry line, served as the main triggering and strengthening factors. The transition from convection triggering to the formation of the initial shape was mainly affected by the convergence line of the SBF, which combined with thermal convection to form the main parts of the SL. In the later stage, the convergence line of the gust front merged with other convergence lines to form a series of strong convective cells. The SBF had good indicative significance in terms of severe convective weather warnings. The suitable conditions of heat, water vapor and vertical wind shear on the Shandong Peninsula were beneficial to the maintenance of the SL. Before SL occurrence, tropopause folding strengthened, which consequently enhanced the baroclinic property in the middle and upper troposphere. The high sensible heat flux at the surface easily produced a positive potential vorticity anomaly in the low layer, resulting in convective instability, which was conducive to the maintenance of these processes. In the system, when precipitation particles passed through the unsaturated air layer, they underwent strong evaporation, melting or sublimation, and the cooling effect formed negative buoyancy, which accelerated the sinking of the air and promoted the sustained development of the surface gale. Together with the development of lowlevel mesocyclones, the air pressure decreased rapidly, which was conducive to gale initiation.
文摘This work discusses issues related to the impact of urbanization on the microphysical processes of precipitating systems associated with synoptic, mesoscale, and local scale systems. Among the issues addressed is the impact of urban heat <span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">island (UHI) in S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center and urban densification (UD) in the</span><span> </span><span style="font-family:Verdana;">Metropolitan Area of S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo (MASP) on the microphysical, dynamic, and</span><span style="font-family:Verdana;"> thermodynamic properties and distribution of precipitation and heavier rainfall from sea-breeze (SB) e cold-front (CF) combined during their space-time evolutions. For this purpose, it used four components: classification of hydrometeors with fuzzy logic, calculation of the raindrop diameters, an estimate of liquid water mass and ice mass from polarimetric-variables measured with dual-pola- rization X-band meteorological radar. The results indicated that urban densification (UD) and heat island (UHI) of the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center impact the formation of precipitation, liquid water mass, and ice mass, depth, and duration of </span><span style="font-family:Verdana;">a thunderstorm. It was also observed the asymmetric configuration of the th</span><span style="font-family:Verdana;">understorm is induced by the strong convergence in the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center, and this strong convergence is induced by the intense heat island (UHI) in the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center. Was also observed that this event that is formed in the Metropolitan Area of S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span>o Paulo (MASP) depends on microphysical processes of mixed-phase of the cloud (water and ice) above the 0<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span>C isotherm for the production of intense rain and cold pool at the surface. These important microphysical processes within long-lasting secondary convective cells over the S<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#F7F7F7;">ã</span></span></span></span>o Paulo city center should be taken into account on convective parameterization schemes as well as the associated cold pool dynamics.</span></span></span></span>
文摘对2007年8月13日天津多普勒天气雷达(CIN RAD WSR/98D)探测的雷暴天气个例进行分析,结果表明:此次雷暴天气是由渤海湾海风锋与阵风锋碰撞形成的;碰撞后,在海风锋前端、阵风锋前部有新的雷暴单体形成;阵风锋后部的对流回波主体加强,对流回波主体由椭圆状加强为典型的弓状。应用天津36个自动气象站的地面六要素资料和北京850 h Pa以上探空资料,组成新的诊断资料,对该个例进行诊断分析,结果表明:雷达探测的海风锋前端具有较强的低层垂直风切变梯度和露点温度梯度大值区,海风锋前沿与0~3 km垂直风切变梯度密集区相对应,且与露点温度梯度变化较快的区域基本吻合;海风锋与阵风锋相互碰撞时,0~3 km垂直风切变在2 h内变化较快,且有明显的增加趋势,CAPE(convective available potential energy,对流有效位能)值在雷暴形成前有较明显增加;随着雷暴天气结束,上述特征随之消失。