河北省层状云降水系统微物理结构的飞机观测研究

【作者】 杨文霞；

【导师】 杜秉玉； 牛生杰；

【作者基本信息】 南京信息工程大学 ， 气象学， 2004， 硕士

【摘要】 本文利用1991年5月25日一次回流天气过程和1992年6月20至21日的西风槽天气过程,总共4个架次的飞行作业中获取的PMS资料,结合部分雷达、探空、雨量资料和已有的成果,从一个新的角度对河北省层状云降水系统的微物理结构进行了分析。在分析过程中,加强了对平飞资料的分析,注重分析了层状云中的一些中尺度组织、高空云带和对流泡的微物理结构特征,采用陶树旺等(2001)提出的层状冷云飞机人工增雨实时监测指标,对冷云进行了可播性判别,对云内的温度变化,如云内逆温等进行了分析。 主要结果表明:在1991年5月25日的回流天气过程中,层状云降水系统存在不均匀性,表现为较强降水云带,空中较强降水云带和地面降雨量具有很好的对应关系。飞机在进入较强云带时,云物理量(LWC、N、D、T)等会产生剧烈变化,表现为LWC跃增、N快速增大、云滴谱谱宽拓宽、T下降等,在同一云带中,温度变化不大并且比周围低。 1991年6月21日个例观测到对流泡位于层积云下部暖云中的部分,泡状结构明显,呈现出中尺度组织特征,天气系统的配置有利于垂直上升运动的发展:通过对比分析,发现对流泡内具有云滴浓度高、液态水含量较高、云谱型相似以及2D-C粒子尺度大等特点:本次个例观测到的对流泡内云滴谱表现为单峰型。 1992年6月20日两次个例的冷云中冰晶尺度、冰水含量(IWC)、冰晶浓度和过冷水含量(LWC)的垂直分布表明,冷云中冰晶尺度随高度降低整体趋势表现为增大,在3400(-1.5℃)～3100m(0℃)增长最快,在此温度区间由于温度较高,冰晶粒子易于攀附和粘连,是本次过程的主要冷云增长过程之一;冰晶浓度的最大值位于4400m(408/L),LWC的最大值位于4000m(0.0802/m~3),与较大冰晶浓度对应的LWC较小,说明冰晶浓度较大的地方消耗掉较多的过冷水。 1991年5月25日个例在飞机上升和下降过程中两次于2000m左右探测到较强的云内逆温,逆温层顶下方存在云水含量的峰值,推测两次云内逆温的形成与大气中的强逆温有关。更多还原

【Abstract】 Based on the PMS data obtained in 4 cases during 25,May 1991,a returning process and 20-21, June 1992,a westerly trough system,meanwhile with some radar , sounding and rainfall data,considering prior results,the microphysical structure of precipitating stratiform clouds in Hebei Province is studied from a new angle. The analysis of the PMS data obtained along level flying routes is enlianced. The microphysical structure of some mesoscale organizations in the stratiform clouds, for example, cloud bands and convective bubbles, is stressly studied. The seeding condition criteria and operation indexes in cold stratiform clouds proposed by Tao Shuwang,et al are used to justice the clouds. The variation of the temperature in the clouds , for example the inversion inside the clouds.is analysed.The main results show: the precipitating stratiform clouds in returning process are inhomogeneous, the strong precipitating cloud bands staying in them. The strong precipitating cloud bands correspond with the ground rainfall well. When the aircraft flies into the bands, the main cloud physical parameters (LWC, N, D and T, et al) changes strongly. The liquid water content (LWC) leap up, the particle concentration (N) grow up rapidly, the spectrum width become wider, the temperature descends.et al. In a same cloud band, the variation of temperature is small meanwhile the temperature is lower.The convective bubbles were observed in the warm clouds under the middle of the cumulostratus on 21,June 1992. The bubbles clearly show that they are one kind of mesoscale organization. It suggests that the synoptic system is situable to produce convective bubbles. It’s contrastly analysed that the particle concentration and the liquid water content are higher.the particle spectra is similar,the particles captured by 2D-C probe are bigger in the bubbles.Inside bubbles the particle spectra is uniform distribution.In the cold clouds of 2 cases on 20,June 1992, vertical distribution of ice size, ice water content(IWC), ice concentration and LWC shows that the ice size increases with decreasing altitude, the most fast increase appears at 3400 (-1.5℃) ~3100m (0℃) where the temperature is higer and the ice particle is easer to accumulate and conglutinate which is the main cold growing process. The maximum ice concentration appears at 4400m (408/L) . The maximum LWC appears at 4000m (0.0802/m~3) .The LWC corresponding to bigger ice concentration is smaller, it is suggest that more supercooled water is consumed.The strong inversion inside clouds is detected twice at about 2000m during up and down on 25,May 1991, the LWC reaches a pea below the top of the inversion. It is更多还原