摘要
利用2004—2010年中国西北四省(区)强对流天气过程高空、地面实况资料,以及近15年西北区强对流研究主要成果,按照强对流天气产生的基本动力学原理,根据其主导因素的不同,将西北区强对流天气基本形势配置分为高空冷平流强迫、低层暖平流强迫、斜压锋生等3类。分析3类基本配置天气尺度环境场显著特征,以及这些特征在中尺度强对流系统发展过程中所起的作用,总结各类配置之间的主要差异及其与中国其他区域的差异。结果表明,高空冷平流强迫类,冷平流可从300 h Pa向下延伸至对流层低层,而850 h Pa则多表现为弱的暖平流。与中国中东部相比,对流层中下层温度递减率更大,层结不稳定在午后会有强烈发展,LFC更高。区域性强对流天气与大范围降水后地面增湿或低层暖湿气流北上有关;局地强对流天气与复杂小地形对应地面抬升和水汽分布不均匀有关。低层暖平流强迫类强对流天气,中低层暖平流占主导作用,湿层可从地面向上延伸到500 h Pa附近,LFC高度明显偏低,温度垂直递减率小于冷平流强迫类。斜压锋生类强对流天气的显著特点是中低层冷暖空气强烈交汇,并伴有明显温度锋区和锋生。水汽条件好于冷平流强迫类,垂直风切变明显高于前两类。
By using the precipitation data of the main convective weather processes from the year of 2004 to2010 in Northwest China,the basic situation configuration of northwest convective weather is divided into three categories by different dominant factors. And, we analyzed the salient features of these three configurations in the field of synoptic-scale environment and the different roles which these features are played in mesoscale convective systems. Meantime,we summarized the main differences among these configurations and also the differences with other regional convective weather configurations. The primary conclusions are as follow: The strong convective weather which is forced by upper air cold advection shows that cold advection may extend downward from 300 h Pa to 700 h Pa, and 850 h Pa is mostly weak warm advection. Compared such kind of convective weather with that occur in the central, eastern of China, temperature lapse rate in the lower troposphere is greater; instability stratification can be stronger in the afternoon;and LFC is higher. Regional convective weather is often associated with ground humidification after large-scale precipitation or lowaltitude warm air moving northward;local strong convective weather is associated with ground uplift of complex terrain and uneven distribution of water vapor. The strong convection weather which is forced by lowlevel warm advection shows that warm advection plays a dominant role in the lower and wet layer extends from ground upward to near 500 h Pa,LFC height is lower significantly. The temperature lapse rate in the lower troposphere is less than the rate in the first situation configuration. The most notable feature of the baroclinic frontogenesis convective weather is the intense interaction between cold and warm air in the lower level,which accompanied with significant temperature frontal zone and frontogenesis. Moisture condition is better than the first situation configuration, vertical wind shear is stronger than the previous two categories significantly.
出处
《高原气象》
CSCD
北大核心
2015年第4期973-981,共9页
Plateau Meteorology
基金
公益性行业(气象)科研专项(GYHY201306006)
中国气象局新技术推广项目(CMAGJ2014M54)
关键词
中国西北区
强对流
形势配置
特殊性
综合分析
Northwest China
Strong convective weather
Situation configuration
Particularity
Comprehensive analysis
