摘要
利用常规气象观测资料、ERA5再分析资料、闪电定位数据和多普勒天气雷达资料等,以中原地区代表性省份-河南省为研究区域,针对其2010-2021年冷季(10月至次年4月)显著高架对流个例进行不稳定机制分类,并对比分析不同机制下雷达回波特征。结果表明:(1)河南省冷季高架对流按照不稳定机制可分为条件不稳定类、条件对称不稳定类、条件不稳定与条件对称不稳定混合类和锋生次级环流触发类4种,其中条件不稳定类占比最多,条件对称不稳定类和混合类次之,锋生次级环流触发类较少。(2)冷季高架对流雷达回波以大范围层积混合回波为主,高架对流单体强度中心值超过40 dBZ,强回波中心高度超过0℃等温层,最大回波顶高在6~10 km。高仰角上存在环状或带状回波的类零度层亮带。(3)条件不稳定类雷达回波中心最强(55~60 dBZ),强回波发展高度和回波顶高最高(8~12 km),出现冰雹概率最高;混合类回波范围广、中心强度较大(40~55 dBZ),对流发展高度与不稳定主导类型有关,回波顶高达8~10 km。条件对称不稳定类和锋生环流触发类回波类似,结构呈条纹状或片状,中心强度较弱(30~45 dBZ),回波纹理均匀,回波发展高度达3 km,最大顶高达6~8 km,对流单体沿热成风方向传播,没有新生单体传播或合并,能够形成冰相粒子和雷暴,但出现雹暴概率较低。(4)径向速度场显示上下层风场不连续,850 hPa以下近地层维持东北或偏东急流,700 hPa以上存在强盛西南急流,较好反映了暖湿气流沿冷垫爬升的天气学特征;低层零速度线呈“S”型弯曲和明显的正负速度中心形成典型的“牛眼”结构,其中以锋生环流类最为显著,条件对称不稳定类次之。
Based on conventional meteorological observation data,ERA5 reanalysis data,lightning location data,and doppler weather radar data,taking Henan province that is the most representative region in central plains as the study area,significant elevated convection cases during the cold season(October to April of the following year)from 2010 to 2021 were classified according to instability mechanisms and the radar echo characteristics under different mechanisms were compared and analyzed.The results show as follows:(1)Elevated convection during the cold season in Henan Province are classified into four categories based on unstable mechanisms:conditionally instability,conditionally symmetric instability,mixed conditionally instability and conditionally symmetric instability and frontal secondary circulation triggering.Among them,conditionally instability class accounts for the largest proportion,followed by conditionally symmetric unstable instability and mixed class,while frontal secondary circulation triggering class accounts for a smaller proportion.(2)The radar echoes of elevated convection during the cold season are mainly large-scale stratiform mixed echoes.The intensity center of individual elevated convection exceeds 40 dBZ and the maximum echo top height is between 6 to 10 km.A ringshaped or banded echo is observed at high elevation angles near the freezing layer.(3)In the radar echoes of conditionally instability class,the strongest center(55~60 dBZ)and the highest development height and echo top height(8~12 km)are observed,with the highest probability of hail.The mixed class echoes have a wide range and a large center intensity(40~55 dBZ)and the development height of convection is related to the dominant instability type,with echo top height reaching 8-10 km.The echoes of conditionally symmetric instability class and frontal secondary circulation triggering class are similar in structure,showing stripe or patchy features,with weaker center intensity(30~45 dBZ),uniform echo texture,development height of echoes up to 3 km and maximum echo top height of 6~8 km.Convection cells propagate along the thermal wind direction,without new cell propagation or merging phenomena,and can form ice-phase particles and thunderstorms,but the probability of hailstorm is relatively low.(4)The radial velocity field shows discontinuity between the upper and lower wind fields,with a northeast or northeast jet stream below 850 hPa and a strong southwest jet stream above 700 hPa reflecting well the meteorological characteristics of warm and humid airflow ascending along the cold pad;the lowlevel zero-velocity line shows an"S"shaped bend and obvious positive and negative velocity centers form a typical"eye"structure,with the frontal secondary circulation class being the most significant,followed by the conditionally symmetric instability class.
作者
武威
许东蓓
WU Wei;XU Dongbei(College of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225,Sichuan,China;Luohe Meteorological Bureau,Luohe 462300,Henan,China)
出处
《高原气象》
北大核心
2025年第3期795-809,共15页
Plateau Meteorology
基金
河南省气象局面上项目(KM202242)
中国气象局航空气象重点开放实验室基金项目(HKQXZ-2024005)。
关键词
中原地区
冷季
高架对流
不稳定机制
雷达特征
central plains
cold season
elevated convection
instability mechanism
radar characteristics
