摘要
利用2003年7月8日的东北冷涡中对流云带的飞机穿云观测资料,结合雷达、卫星云图及天气图等资料,详细分析了此次冷涡对流云带的宏观特征、微物理结构,并对降水形成机制进行初步探讨。此次东北冷涡对流云系具有明显的带状水平回波结构,中等强度,垂直尺度小(小于6 km),云过冷液态水含量丰富,最大可达3.3 g/m3,云的上部过冷水含量也达到2.0 g/m3。对流云带的上部存在冰粒子高浓度区,最大值为1062 L-1,出现在5242 m(-6.8℃)处,这些冰粒子在高过冷水含量区的快速长大对降水产生起到重要作用。云滴直径与云滴浓度在0℃层附近呈现负相关性;通过分析解释了上升气流强的区域有更小的云滴粒子和冰晶粒子的原因,上升气流的作用造成了0℃层以下粒子浓度的积累。在弱上升气流区,2-DC观测的粒子浓度,高浓度区对应小粒子多,低浓度区对应大粒子多。并初步探讨了冷涡对流云带可能存在冰晶繁生过程。
A detailed analysis of macro/microstructure for convective rainbands of a mesoscale cold vortex over Northeast China has been conducted based on data including airborne PMS （Particle Measuring System）, radar, satellite and weather chart etc., obtained from field campaign on 8 July 2003 in Jilin Province, and the precipitation formation mechanism is preliminarily discussed. The results show that the northeastern cold vortex had apparent horizontal band echo structure with middle intensity and small vertical height （less than 6 km）, but it had high supercooled water content with a maximum value of 3.3 g/m^3 , the supercooled water content even reaches 2. 0 g/m^3 at upper levels of cloud. High number concentration of ice particles is observed, the maximum value reaches 1062 L^-1 at 5242 m AGL （-6.8℃）, the rapid growth of these particles in the region of high supercooled water content has an important contribution to precipitation formation. High concentration of ice crystals at the top of cloud plays a major role in maintaining precipitation. A negative correlation between the number concentration and the diameter of cloud particles is found near 0℃ layer. The number concentration of droplets or ice particles in the region of strong updraft is smaller than that in the region of weaker updraft. The accumulation region of particle concentration is found below 0℃ layer due to the updraft effect. The 2 -DC probe shows that high number concentration corresponds to small-size particles while low number concentration corresponds to large-size ones. The ice multiplication process possibly existing in cloud is also preliminarily discussed.
出处
《大气科学》
CSCD
北大核心
2007年第4期621-634,共14页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金资助项目40333033
40537034
吉林省气象局开放式基金课题
中国气象局
吉林省人民政府人工影响天气联合开放实验室课题
关键词
东北冷涡
对流云带
微物理结构
飞机探测
Northeast China cold vortex, convective rainband, microphysical structure, exploration
