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1.
霰粒子参数对强对流云降水和催化影响的数值模拟研究 总被引：1，自引：0，他引：1
本文利用三维对流云AgI催化模式, 开展了霰粒子密度和落速参数的敏感性模拟试验, 以研究高凇附度时霰粒子参数的选取对催化模拟结果的影响。敏感性试验中对七个霰微物理过程进行了调整。分析发现改变霰落速参数和霰密度, 可以引起3小时模拟的总降水量增加4.9%。催化后改变了敏感性试验中霰落速和上升气流的配置, 并影响到霰碰并云水和冰晶的过程, 及霰融化成雨水的过程。在高凇附度云中如果只增加霰密度而没有增加相应的落速系数, 将使云中霰含量大幅增加。霰参数也影响了自然云和催化云的降水效率。过量催化使得催化云的降水效率低于自然云。增加霰密度的同时也增加霰落速系数, 将使其降水效率高于对照试验, 从而影响催化效果。在高凇附度云中采用大密度和较大下落系数, 并且利用比数浓度平均落速计算霰粒子比数浓度的下落过程, 会使催化效率从25%减少到15%, 极大地改变催化效果。所以在高凇附度的暴雨个例中, 应当采用高霰密度和相应的高霰落速, 否则减雨的催化效果将会被大幅夸大。 相似文献
2.
强风暴电过程对霰粒子含量和谱分布影响的数值模拟研究 总被引：2，自引：0，他引：2
利用建立的耦合电过程三维冰粒子分档模式(通过引入电场力来考虑电场对粒子的影响),模拟研究了北京一次强雷暴发展过程中电过程对霰粒子含量、数浓度的影响。结果发现:(1)相对小的霰粒子含量受电过程直接影响较大,这种影响累积后,会对相对较大的霰粒子含量产生间接作用。在冰雹发展的初期和成熟期的部分阶段,电场对霰粒子最大含量所处空间位置基本没有影响。而在冰雹发展的成熟期向衰败期过渡时的部分时刻,电场对其稍有影响。在霰粒子最大含量处,直径相对较大的霰粒子决定着总的霰粒子含量。(2)总体来说,直径较小的霰粒子数浓度受电场影响较大,直径较大的霰粒子数浓度受电场影响较小。由于霰粒子含量中心大直径粒子较多,而其受电场的影响相对较小,并且该处电场也小于电场极值,故其最大含量受电场影响相对较小。所以,在此次个例的模拟过程中,霰粒子最大含量的时变曲线变化很小。(3)考虑电过程情况下,在霰粒子数浓度最大处,小直径霰粒子数浓度要么增加,要么略微减少,而大直径霰粒子要么进档增长受阻,要么数浓度减少。对不同直径的霰粒子来说,电过程既有可能使其数浓度增加,又有可能使其数浓度减少。当电场较大时,电过程对小直径霰粒子的影响比较直接,而对大直径霰粒子的... 相似文献
3.
霰粒子下落速度对云系及降水发展影响的数值研究 总被引：1，自引：0，他引：1
云和降水的形成是动力过程与微物理过程相瓦作用的产物,云数值模式中的微物理过程参数化方案对云和降水发展过程有直接影响.在云数值模式中,粒子群体的下落速度都足用质量加权下落末速度公式来表达,而且不同的模式采用的公式存在差异,质量加权下落末速度中参数取值不同,引起的粒子下落末速度不同.为了了解粒子下落末速度变化对云系和降水发展的影响,对2004年8月12日一次冷锋降水过程,利用中尺度ARPS模式做模拟研究.在分析降水机制的基础上,对霰这一下落末速度较大的降水粒子,做下落末速度(Vg)的敏感性试验,从动力、热力、微物理的角度,通过数值模拟对比分析了霰下落末速度减小对降水分布和强度、云系的移动、云系的宏观热力和动力场的影响,并给出了影响的途径和机理.结果表明:Vg变化对云的厚度和含水量有影响,下落末速度减小对冰晶、雪、霰的含水量垂直分布及分布随时间变化影响较大,其中,霰的含水量显著减少,雪的含水量增加,并调整了云中水质粒的空间分布;Vg减小对地面累积总降水量的分布影响较小,但对降水强度的分布影响较大.Vg减小时,降水强度减小,降水时间延迟,因此,霰下落末速度变化将调整底层降水分布;对于云系的移动情况基本上没有影响,但对云中水质粒的空间分布有影响;霰下落末速度变化影响云中霰的融化和撞冻增长从而影响热力场.末速度减小时,霰和雪的融化罱明显减小,导致非绝热冷却率的减小,引起下沉气流的减小. 相似文献
4.
利用三维云起电放电模式, 通过对2008年9月6日北京地区一次雷暴过程的模拟, 研究了云内雨滴、冰晶、霰和雹4种粒子对云内闪电活动的直接影响。对比几种主要冰相粒子比质量浓度的分布变化与模拟闪电开始发生高度的关系, 并分析几种冰相粒子所带电量变化率的时空变化特征后发现:霰和冰晶是对云内闪电发生作用最为重要的两种粒子; 雹粒子对闪电发生作用有限; 雨滴则对于主电荷区附近闪电发生没有直接影响。模拟结果表明:在实际观测中出现的雷达强回波达到某个高度之上可以预警闪电发生的现象, 主要是由于霰粒子在一定高度之上与冰晶之间发生强烈的电荷分离, 从而使云内电场迅速增强, 并最终引发闪电而导致的。 相似文献
5.
使用中尺度数值模式(WRFV3.7.1)对发生在宁夏南部山区两次降雹天气过程的背景场特征、云宏微观结构以及云内微物理转化机制进行了数值研究。结果表明:该地区冰雹云形成的大气环境水汽含量较少,冰雹的发生主要依靠"上干下湿"的不稳定层结及午后局地加热效应。两次个例发生的环境水汽含量存在较大差异,导致两次雹云个例微物理结构演变特征不同。对数值模拟结果分析发现,宁南山区冰雹云中雪粒子含量较多,雹胚(霰粒)主要通过雪粒子转化而来。霰粒主要通过水汽凝华及碰并过冷云水增长。模拟云中冰雹形成高度相对较低,冰雹形成后主要通过收集过冷云水增长。除碰冻过冷云水外,对过饱和水汽的凝华也是雪、霰、雹粒子质量增长的一个重要来源。模拟得到该地区冰雹云中云雨自动转化过程较弱,雨水主要是通过雪、霰、雹粒子在下落过程中融化形成。雨水在下落过程中蒸发显著。 相似文献
6.
“碧利斯”(0604)暴雨过程不同类型降水云微物理特征分析 总被引：2，自引：3，他引：2
本文利用"碧利斯"(0604)暴雨增幅过程高分辨率的数值模拟资料, 将降水分成对流降水和层云降水, 对比分析了不同类型降水云微物理特征和过程的差异, 探讨了不同类型降水对暴雨增幅的贡献, 结果指出:(1)暴雨增幅前, 降水基本为层云降水, 对流降水只存在于零星的几个小区域, 暴雨增幅发生时段, 对流降水所占比例较暴雨增幅前有显著增加, 平均降水强度达层云降水强度的3倍多。(2)暴雨增幅时段, 云系发展更加旺盛, 云中各种水凝物含量较增幅前明显增加, 其中, 对流和层云降水区云中水凝物含量均有一定程度增长, 但对流降水区增加更显著;而无论增幅前还是增幅时段, 对流降水区云中水凝物含量均要明显大于层云降水区, 并且两者的这种差异随着地面降水强度的增强而增大。(3)暴雨增幅前后, 对流降水区雨滴的两个主要来源最终均可以追踪到云水, 通过云水与大的液相粒子(雨滴)和大的固相粒子(雪)之间、以及大的固相粒子(雪和霰)之间的相互作用和转化, 造成雨滴增长, 并最终形成地面降水, 而层云降水区中与雨滴形成相关的上述主要云微物理过程明显变弱, 但层云降水区中暴雨增幅时段的上述过程又要强于增幅前, 说明层云降水对暴雨增幅也有一定贡献。 相似文献
7.
不同云底温度雹云成雹机制及其引晶催化的数值研究 总被引：24，自引：1，他引：23
用二维准弹性冰雹云模式模拟了中国不同地区的冰雹云的成雹机制和人工引晶催化的效果,结果表明：强对流云中自然初始降水元的形成主要同云雨自动转化相关;云底温度较低的冰雹云的雹胚形成以云霰转化过程为主,暖云底的雹云则以雨霰转化为主。人工引晶的作用有三：（１）加强云中冰霰转化过程,雹胚过多争食防雹;（２）促进雨霰转化过程,使雹胚浓度增加,并且减少过冷雨滴,抑制冰雹碰冻过冷雨滴的增长;（３）使云的下部霰量增加,降低降水粒子的增长轨迹,阻碍霰雹的增长。多次催化有时比一次大剂量催化的防雹增雨效果好。 相似文献
8.
为提高双偏振天气雷达雷暴监测预警能力,探究雷暴活动过程雷达偏振信息特征及雷暴内部微物理过程,利用S波段双偏振多普勒天气雷达,结合地面大气电场仪和闪电定位系统资料对2015年8月31日发生在南京地区一次局地强雷暴过程进行了分析。主要利用体扫数据获得雷暴单体内部垂直剖面(Vertical Cross Section,VCS),同时结合模糊逻辑算法进行粒子类型识别,得到多个偏振参量和雷暴云内部粒子类型的垂直分布情况,进一步分析得到各偏振参量和粒子分布随闪电活动的演变规律。结果表明:在-15℃高度层以上冰晶区域出现K_(DP)的负值区与闪电活动具有很好的相关性;雷暴云中霰粒子的分布变化同闪电活动演变同步很好,在一定高度霰粒子的出现可以用来对雷暴进行预警;雷暴云中低层存在强烈的辐合上升区,利于霰和冰晶碰撞非感应起电和闪电的发生。 相似文献
9.
云中粒子谱形状因子变化对云及降水影响的数值研究 总被引：5，自引：2，他引：5
鉴于目前云数值模式和中尺度数值模式中云和降水过程大多用体积水参数化的方式描述,而不同模式所用的粒子谱不同或粒子谱的参数不同,用这些模式模拟研究云和降水的物理过程、降水形成机制、催化防雹和催化增雨机理以及预报降水等就遇到这样一个问题:粒子谱或谱参数不同对研究结果有何影响?因此利用中国科学院大气物理研究所的三维冰雹云催化数值模式,做雹云中粒子谱参数变化的数值试验,分析了冰雹云中雨滴谱、冰晶谱、霰谱的形状参数对降雨降雹、云中微物理过程的影响。结果表明,雨滴谱形状参数变化,对降雨形成机制基本没有影响,对与雨滴有关的物理过程有直接影响。霰谱对地面降雹量、降雹强度、雨强的影响较大,对降雨量影响较小;对冰晶、霰以及冰雹的质量和数量产生率都有明显的影响,云中的所有微物理过程均受到了不同程度的影响,对有些过程影响最为显著,它不但影响粒子的产生过程,也影响粒子的增长过程。冰晶谱对降水量的影响较小,但对各种粒子的某些形成或增长过程影响较大,有的很大。此外,冰晶谱型的变化,对不同地区云或不同个体云降水的影响程度不同,反映了滴谱谱型对云和降水影响的复杂性。利用这些研究结果,讨论了云模式的使用问题。 相似文献
10.
雷暴微物理过程对电活动影响的数值模拟研究 总被引：2，自引：0，他引：2
在一维时变雷暴云起电放电模式的基础上,分别利用对流降水试验合作计划(CCOPE)和夏季雷暴放电与降水研究(STEPS)一次雷暴的实测探空资料进行了初步模拟,并通过敏感性试验研究了软雹垂直通量、地面温度和反转温度对雷暴云起电放电过程的影响.模式考虑的冰晶生成机制为Fletcher 和H-M冰晶生成机制.对比CCOPE和STEPS雷暴个例的模拟与观测结果,发现垂直电场正负极大值出现的位置与实测结果较接近,但电场极值差异较大,模拟结果明显大于实测结果.敏感性试验表明,当软雹垂直通量增加时,雷暴云首次放电时间降低,而单位时间内发生闪电的次数(闪频)随之增大.当地面温度较高时,雷暴云中负电荷的垂直厚度较小,雷暴云的正、负电荷最大密度较大.当反转温度较低时,冰晶所带负电荷的垂直范围较大.在敏感性试验中,当模式中地面温度为32℃,反转温度＜-26℃时,雷暴云出现反极性电荷结构.该模式能较直观地模拟雷暴发展过程中的电荷结构和电场时空分布等. 相似文献
11.
High-resolution numerical simulation data of a rainstorm triggering debris flow in Sichuan Province of China simulated by the Weather Research and Forecasting (WRF) Model were used to study the dominant cloud microphysical processes of the torrential rainfall. The results showed that: (1) In the strong precipitation period, particle sizes of all hydrometeors increased, and mean-mass diameters of graupel increased the most significantly, as compared with those in the weak precipitation period; (2) The terminal velocity of raindrops was the strongest among all hydrometeors, followed by graupel’s, which was much smaller than that of raindrops. Differences between various hydrometeors’ terminal velocities in the strong precipitation period were larger than those in the weak precipitation period, which favored relative motion, collection interaction and transformation between the particles. Absolute terminal velocity values of raindrops and graupel were significantly greater than those of air upward velocity, and the stronger the precipitation was, the greater the differences between them were; (3) The orders of magnitudes of the various hydrometeors’ sources and sinks in the strong precipitation period were larger than those in the weak precipitation period, causing a difference in the intensity of precipitation. Water vapor, cloud water, raindrops, graupel and their exchange processes played a major role in the production of the torrential rainfall, and there were two main processes via which raindrops were generated: abundant water vapor condensed into cloud water and, on the one hand, accretion of cloud water by rain water formed rain water, while on the other hand, accretion of cloud water by graupel formed graupel, and then the melting of graupel formed rain water. 相似文献
12.
I. Geresdi 《Atmospheric Research》1998,45(4):237-252
One of the purposes of the Fourth Cloud Modeling Workshop was to compare different microphysical treatments. In this paper, the results of a widely used bulk treatment and five versions of a detailed microphysical model are presented. Sensitivity analysis was made to investigate the effect of bulk parametrization, ice initiation technique, CCN concentration and collision efficiency of rimed ice crystal–drop collision. The results show that: (i) The mixing ratios of different species of hydrometeors calculated by bulk and one of the detailed models show some similarity. However, the processes of hail/graupel formation are different in the bulk and the detailed models. (ii) Using different ice initiation in the detailed models' different processes became important in the hail and graupel formation. (iii) In the case of higher CCN concentration, the mixing ratio of liquid water, hail and graupel were more sensitive to the value of collision efficiency of rimed ice crystal–drop collision. (iv) The Bergeron–Findeisen process does not work in the updraft core of a convective cloud. The vapor content was always over water saturation; moreover, the supersaturation gradually increased after the appearance of precipitation ice particles. 相似文献
13.
两次飑线过程中短时强降水和冰雹强度差异及成因分析 总被引：5，自引：2，他引：3
利用常规观测资料、雷达反射率资料和NCEP/NCAR提供的FNL再分析资料,结合中尺度非静力模式(WRF)的模拟结果,分析了2009年6月3—6日两次飑线过程的环境背景、移动路径以及短时强降水和冰雹强度的差异及其产生的原因。结果表明:移动路径的差异主要由500 hPa以下引导气流不同造成。数值模拟和水汽试验得出,两次过程在垂直方向的水汽条件存在明显差异可能是短时强降水及冰雹强度不同的主要原因。700~850 hPa水汽的多少对霰(雹)比含水量的大小非常敏感,这一区域的水汽增多,则霰(雹)比含水量明显增加,反之,有明显减少。 相似文献
14.
Numerical Simulation of Macro- and Micro-structures of Intense Convective Clouds with a Spectral Bin Microphysics Model 总被引：1，自引：0，他引：1
By use of a three-dimensional compressible non-hydrostatic convective cloud
model with detailed microphysics featuring spectral bins of cloud
condensation nuclei (CCN), liquid droplets, ice crystals, snow and graupel
particles, the spatial and temporal distributions of hydrometeors in a
supercell observed by the (Severe Thunderstorm Electrification and
Precipitation Study) STEPS triple-radar network are simulated and analyzed.
The bin model is also employed to study the effect of CCN concentration on
the evolution characteristics of the supercell. It is found that the CCN
concentration not only affects the concentration and spectral distribution
of water droplets, but also influences the characteristics of ice crystals
and graupel particles. With a larger number of CCN, more water droplets and
ice crystals are produced and the growth of graupel is restrained. With a
small quantity of CCN the production of large size water droplets are
promoted by initially small concentrations of water droplets and ice
crystals, leading to earlier formation of small size graupel and restraining
the recycling growth of graupel, and thus inhibiting the formation of large
size graupel (or small size hail). It can be concluded that both the macroscopic
airflow and microphysical processes influence the formation and growth of large
size graupel (or small size hail). In regions with heavy pollution, a high
concentration of CCN may restrain the formation of graupel and hail, and in
extremely clean regions, excessively low concentrations of CCN may also limit
the formation of large size graupel (hail). 相似文献
15.
A multiparameter radar case study of the microphysical and kinematic evolution of a lightning producing storm 总被引：7，自引：0，他引：7
Summary We examine the co-evolving microphysical, kinematic, and electrical characteristics of a multi-cell thunderstorm observed on 21 May 1993 along the Front Range of Colorado using data collected with the 11 cm, multiparameter, CSU-CHILL Doppler radar. The measured polarimetric variables provide information on the size, shape, orientation, and thermodynamic phase of hydrometeors. Recent modeling and observational advances in weather radar polarimetry now permit the inference of bulk-hydrometeor types and mixing ratios, and the measurement of precipitation rate in mixed-phase (i.e., hail and rain) environments. We have employed these and other radar techniques, such as dual-Doppler analyses, to investigate the correlation between the convective life cycle of a multi-cell storm and the evolution of lightning type and flash rate.The observations suggest a strong correlation between the radar-inferred graupel volume suspended in a vigorous updraft in upper-portions of the storm and the in-cloud (IC) lightning flash rate. Our analyses reveal that maxima in the hail rate are related to peaks in the cloud-to-ground (CG) lightning flash rate. Both correlation's are consistent with the non-inductive charging mechanism which relies on collisions between graupel/hail particles and ice crystals in the presence of supercooled water. Peaks in storm outflow are shown to either lag or to coincide with maxima in both the CG flash rate and hail rate. The amount and vertical location of ice in this storm was also related to the strength and polarity of the electric field through observations of a Field Excursion Associated With Precipitation (FEAWP) and a subsequent microburst. We demonstrate that the FEAWP was coincident with the descent of graupel and small hail below the charge reversal level as explained by the non-inductive charging mechanism, and that the further descent of graupel and small hail below the melting level aided in the generation of a microburst near the surface. Using observations of the FEAWP, we present some comparative speculation on the microphysics of the associated lower positive charge center and the applicability of various laboratory charging studies.With 14 Figures 相似文献
16.
三维强风暴动力-电耦合数值模拟研究Ⅰ:模式及其电过程参数化方案 总被引：14，自引：2，他引：14
为了研究风暴中的动力、微物理和电过程三者间的相互作用 ,在已有的工作基础上 ,建立了一个三维强风暴动力 电耦合数值模式。模式中将云中水物质分为水汽、云水、雨水、冰晶、雪、霰和雹 7类 ,各种粒子采用双变参数谱。考虑了详细的起电过程 ,它们包括扩散、电导、感应和非感应以及次生冰晶起电机制。此外 ,在模式中加入了云内放电参数化过程和云顶处屏蔽电荷层形成的参数化方案用以研究整个雷暴生命史内的电活动特征。最后利用CCOPE(CooperativeConvectivePrecipitationExperiment)计划中 1981年 7月 19日的风暴资料对模式的性能进行了验证 ,模拟结果显示此模式可以较好地描述风暴中动力、微物理和电结构的发展演变过程。 相似文献
17.
为探究贵州省威宁地区雹暴过程中雹胚粒子的演变特征,本文在对X波段双线偏振雷达数据经过退折叠、滤波、自适应衰减订正后,运用Barnes插值方法对偏振参量进行插值,并结合模糊逻辑算法进行水成物粒子识别,然后对威宁县的两次典型雹暴过程进行了系统的分析,得到以下结论:（1）两次过程中高密度霰的来源均为冰晶聚合物和冻滴,低密度霰粒子的来源均为冰晶粒子;单体雹暴过程中高密度霰粒子对冰雹的产生贡献最大,多单体雹暴过程中低密度霰粒子对冰雹的产生贡献最大。（2）多单体雹暴中,衰减单体的高空辐合以及低空辐散对发展单体的雹胚形成有促进作用。（3）单体雹暴降雹前:低密度霰粒子数量近乎不变;由于冰晶聚合物增多使得消耗过冷水粒子速度加快,导致过冷水粒子减少,而且有部分高密度霰粒子坠落至地面,导致高密度霰粒子数量减少,每分钟减少的距离库数为10;降雹时:高密度霰粒子淞附过冷水粒子增长形成冰雹,导致高密度霰粒子减少,每分钟减少的距离库数为12.1;而在“贝吉龙过程”（即Wegener-Bergeron-Findeisen过程,简称WBF）以及冰晶聚合物的淞附作用下,低密度霰粒子迅速增多,每分钟增加的距离库数为36;降雹后:低密度霰粒子坠落,数量快速减少,每分钟减少的距离库数为36.6;低密度霰粒子在下降过程中淞附过冷水、冰晶聚合物等粒子转化成高密度霰粒子,导致高密度霰粒子总量几乎不变,每分钟增加的距离库数为2。（4）多单体雹暴降雹前与单体雹暴类似,不同的是在消散单体的促进作用下,发展单体的发展速度、雹胚数量、回波强度均高于单体雹暴;降雹时:低密度霰粒子在下落过程中淞附过冷水滴增长形成冰雹,导致数量迅速减少,每分钟减少的距离库数为62.6;高密度霰粒子数量增加,每分钟增的距离库数为16.5;由成熟到降雹的时间比单体雹暴长15分钟左右;降雹后与单体雹暴类似。（5）通过对威宁地区雹暴机制的分析,分别建立了单体雹暴、多单体雹暴的概念模型。本文针对两种典型雹暴的各个过程中雹胚的演变特征研究得到了初步结果,这对于雹暴预警、预报以及人工消雹具有较高的应用价值。 相似文献
18.
为了更好的基于X波段双线偏振雷达,开展强对流天气的监测与预警、云内微物理过程等的应用研究,本文对该雷达的质量控制方法及云内水成物粒子识别方法进行了较系统的比较分析,得到的主要结论如下:(1) 采用径向连续性检查的方法对差分传播相移进行相位退折叠后,其连续性明显提升。对差分传播相移进行滤波处理,其小波去噪明显优于滑动平均和中值滤波。经自适应约束算法进行衰减订正后,其值与S波段雷达差异减小,且强回波区回波强度增幅比弱回波区明显,可达5dBZ。(2) 基于模糊逻辑算法能较好地解决阈值重叠问题,有效识别毛毛雨(DR)、雨(RA)、干雪(DS)、干冰晶(DC)、湿雪(WS)、干霰(DG)、湿霰(WG)、小冰雹(SH)、大冰雹(LH)和雨夹雹(RH)10种水成物粒子。此外,环境温度的引入对解决0℃层以下液态与冰相粒子混合,以及其他粒子分布不合理的现象有较明显的帮助。至此,建立了一套基于检查径向连续性-小波去噪-自适应约束算法-加入环境温度的模糊逻辑算法的质量控制及粒子识别方法。 相似文献
19.
Summary Seven different microphysical sensitivity experiments were designed with an objective to evaluate their respective impacts
in modulating hurricane intensity forecasts using mesoscale model MM5. Microphysical processes such as melting of graupel,
snow and cloud ice hydrometeors, suppression of evaporation of falling rain, the intercept parameter and fall speed of snow
and graupel hydrometeors are modified in the existing NASA Goddard Space Flight Center (GSFC) microphysical parameterization
scheme. We studied the impacts of cloud microphysical processes by means of track, intensity, precipitation, propagation speed,
kinematic and thermodynamic vertical structural characteristics of hurricane inner core. These results suggest that the set
of experiments where (a) melting of snow, graupel and cloud ice were suppressed (b) melting of snow and graupel were suppressed
and (c) where the evaporation of rain water was suppressed all produced most intense storms. The major findings of this study
are the interconversion processes such as melting and evaporation among hydrometeors and associated feedback mechanism are
significantly modulate the intensity of the hurricane. In particular an experiment where the melting of graupel, snow and
cloud ice hydrometeors was eliminated from the model parameterization scheme produced the most explosively intensified storm.
In the experiment where rain water evaporation was eliminated from the model, it produced a stronger storm as compared to
the control run but it was not as strong as the storms produced from absence of melting processes. The impact on intensity
due to variations made in intercept parameters of the hydrometeors (i.e., snow and graupel) were not that evident compared
to other experiments. The weakest storm was noted in the experiment where the fall speeds of the snow hydrometeors were increased
two fold. This study has isolated some of the factors that contributed to a stronger hurricane and concludes with a motivation
that the findings from this study will help in further improvement in the design of sophisticated explicit microphysical parameterization
for the mesoscale non-hydrostatic model for realistic hurricane intensity forecasts. 相似文献
20.
It has been found that air bubbles, which exhale during freezing of overcooled cloud drops on the hail or graupel particles surface, carry away a great amount of positive charge to the surrounding space while the compensating negative charge remains on the solid particles of hydrometeors. This conception was used for computation of rates of charge accumulation on the hail particles and generation of thunderstorm electricity in deep convective clouds. It is shown that this conception describes the most powerful mechanism of thunderstorm electricity generation and satisfies all the requirements for the theory of thunderstorm electricity. 相似文献