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1.
本文以GFS资料为初始场,利用WRF（v3.6.1）模式对2015年第22号台风“彩虹”进行了数值研究。采用CMA（中国气象局）台风最佳路径、MTSAT卫星、自动站降水为观测资料,对比了4个微物理方案（Lin、WSM6、GCE和Morrison）对“彩虹”台风路径、强度、结构、降水的模拟性能。模拟发现上述4个云微物理方案都能较好地模拟出“彩虹”台风西行登陆过程,但是其模拟的台风强度、结构及降水存在较大差异;就水成物而言,除GCE方案对雨水的模拟偏高以外,其他方案对云水、雨水过程的模拟较为接近,其差异主要存在于云冰、雪、霰粒子的模拟上。本文对比分析了WSM6和Morrison两个方案模拟的云微物理过程,发现WSM6方案模拟的雪和霰粒子融化过程显著强于Morrison方案,但是冰相粒子间转化过程的强度明显弱于Morrison方案。云微物理过程的热量收支分析表明:WSM6方案模拟的眼区潜热更强,暖心结构更为显著,台风中心气压更低。细致的云微物理转化分析表明,此次台风降水的主要云微物理过程是水汽凝结成云水和凝华为云冰;生成的云水一方面被雨水收集碰并直接转化为雨水,另一方面先被雪粒子碰并收集转化为霰,然后霰粒子融化成雨水;而生成的云冰则通过碰并增长转化为雪。小部分雪粒子通过碰并收集过冷水滴并淞附增长为霰粒子,随后融化为雨水,大部分雪粒子则直接融化形成地面降水。 相似文献
2.
利用WRF模式中三种云微物理参数化方案(Lin、Eta和WSM6)对青藏高原一次强降水过程进行模拟试验,将模拟降水结果与实测资料进行对比,以评估不同云微物理参数化方案对该区域降水过程的模拟性能。结果表明:三种方案均能够模拟出此次降水天气过程的发生,但在主要降水区域和降水强度两方面仍与实测资料存在偏差;在水凝物方面,三种方案对冰粒子的模拟较接近,Lin和WSM6方案模拟的雪粒子差异较大,但霰粒子无明显差异。进一步对比分析了Lin和WSM6方案模拟的云微物理转化过程,结果表明:这两种方案都表现出了霰向雨水转化的特点。在Lin方案中,通过水汽向霰粒子凝华、霰碰并水汽凝华生成的雪粒子以及霰碰并云水这三种过程生成的霰粒子最终融化为雨水。而在WSM6方案中,一方面水汽凝结成云水,云水被雪和霰粒子碰并收集转化为霰,之后霰融化为雨水;另一方面水汽凝华为冰粒子,一部分冰转化为雪,雪直接融化为雨水或转化为霰融化为雨水,另一部分冰转化为霰,霰融化为雨水。 相似文献
3.
利用非静力平衡中尺度数值模式MM5,在四重嵌套网格区域内采用Reisner霰方案,对2009年2月12—13日辽宁雨夹雪转暴雪天气过程进行数值模拟,并对云内微物理过程特别是对雨水、雪和霰的源项进行分析。结果表明：雨水与雪碰并和雨水与云水碰并是产生雨水的主要微物理过程,并且雨水的增长主要分布在700hPa以下。300hPa—200hPa之间雪的凝华增长、冰晶向雪的自动转化和900hPa以下雨水与雪碰并成雪是雪增长主要的物理过程。冰晶向雪的自动转化对降雪的增长和长时间维持起到了重要作用。列出了此次天气过程降水云系的三层云结构及微物理过程模型。 相似文献
4.
一次飑线过程的云微物理参数化方案数值试验及其成因分析 总被引：2，自引：1，他引：1
利用WRF模式6种适合高分辨率且包含多种固态水成物粒子的云微物理参数化方案,分别对2012年5月16日江苏北部一次飑线过程进行数值试验,结果表明:LIN方案模拟的飑线回波反射率、强降水TS评分、结构和强度等均要优于其余5种微物理参数化方案。分析不同参数化试验结果中不同水成物粒子占比随时间的变化特征,并针对LIN方案采取敏感性试验和水成物转化微物理过程分析指出,在此次飑线过程中的各水成物粒子中,霰/雹粒子占比最大,是降水过程中最重要的粒子;地面降水直接来源是雨水,雨水主要来源于中层霰/雹粒子的融化,小部分来源于云水的自动转化;中层霰/雹粒子最主要来源是通过雨霰转化过程中的雨水撞冻冰雹微物理过程,其次是霰撞冻云水的微物理过程,而冰相物质雪晶和云冰的碰并、撞冻和自动转化过程微乎其微。 相似文献
5.
20世纪利用一维层状云模式对2002年4月4~5日河南省冷锋降水过程进行了模拟。数值模拟结果显示,此次冷锋降水属于冷云降水过程,冷锋前后云中主要以冰相粒子为主,云中水质粒自上而下的空间分布依次为冰晶、雪、云水、霰、雨水。冷锋前后,各种水质粒有着不同的含量及数密度,但形成水质粒的主要微物理过程都表现为:冰晶数密度的增加主要依靠核化、繁生,大部分雪主要靠凝华、撞冻过冷云水和冰晶增长,霰的质量增加主要靠撞冻雪、过冷云水和雪自动转化而来,大部分的雨水是由霰融化而来,因而此次冷锋降水机制表现为“水汽—雪—霰—雨水”。 相似文献
6.
MM5中新显式云物理方案的建立和数值模拟 总被引：13，自引：3，他引：10
在MM5动力框架内, 在其中Reisner 2方案基础上采用双变参数方案, 增加了云水、雨水、雪和霰的数浓度预报方程.云中凝结核CCN的数浓度采用超几何函数表示; 云水向雨水的自动转换过程考虑了云滴谱的特征和发展变化对该过程的影响, 而不是采用原方案给定阈值的方法描述该过程; 对连续碰并方程不再将粒子落速差作为常量提出积分号外, 而是直接作为粒子直径函数在积分号内求解, 这样处理可以回避使用粒子群的平均落速带来的误差; 增加了霰和雪、霰和冰晶的碰并微物理过程.粒子引入Г分布谱函数, 对微物理过程采用了与之 相似文献
7.
华北暴雪的云微物理参数化方案的比较模拟 总被引：7，自引：3，他引：4
用MM5模式模拟2004年12月20-23日发生在华北地区的一次暴雪天气的发生发展及其演变过程.在四个嵌套网格区域内分别采用Goddard方案(试验G)和Reisner 2方案(试验R)的两个纯显式冰相云微物理参数化方案进行试验.模拟结果表明:试验G和试验R均可以较好的模拟暴雪过程中的环流形势演变、降雪分布和强度,并且两个试验的结果差别不大,但是云中的微物理过程有很大的不同.试验G的主要云微物理过程包括云水的凝结增长、云冰的凝华增长、云冰初始化、云冰被雪碰并、云水被雪碰并、雪的凝华增长、云冰的Bergeron过程等;而试验R的主要云微物理过程包括云冰的凝华增长、云冰转化成雪、雪的凝华增长和霰的凝华增长等. 相似文献
8.
一次梅雨锋暴雨云物理特征的数值模拟研究 总被引：4，自引：1，他引：3
利用中尺度数值模式MM5(V3.6),选用模式中不同的显式云物理方案,对2003年7月4-5日发生在江淮流域的梅雨锋暴雨过程进行了数值模拟,并根据模拟结果对造成此次暴雨过程的对流云团的微物理特征进行了分析.研究结果表明:(1) 具有详细云物理过程的中尺度模式MM5对短时强降水过程具有较好的模拟能力,提高MM5模式的分辨率,可以更好地模拟短时梅雨锋暴雨过程,模式中的Goddard云物理方案的模拟结果要优于Reisner方案和Schultz方案.(2) 梅雨锋对流云团是一种复杂的固、液、气三相混合体结构,在云体区域内的平均质量密度分布中,水汽的质量密度最大,其次是霰,而冰晶、雪、云水和雨水的质量密度较小且数值大小彼此接近,各种相态粒子质量密度峰值出现的高度随时间无明显变化.雨水、云冰和霰的质量密度随时间演变规律与地面降水强度的变化特征相一致,近地面层水汽密度随时间的演变规律比地面降水强度提前1-2个小时,水汽通量的辐合对暴雨时段内水汽的补充和维持起到了重要的作用.(3) 除了最基本的云水向雨水转化的云微物理过程之外,此次降水过程还显示,在中层500-700 hPa范围内雪、冰晶等冰相粒子首先转化为霰粒子,而霰和云水的结合进一步加速(剧)云水向雨水的转换,成为短时特大暴雨形成不可或缺的动力机制,云物理过程中的相变潜热与对流运动的正反馈机制是促进暴雨维持和发展的最重要热力因子. 相似文献
9.
Cloud microphysical differences with precipitation intensity in a torrential rainfall event in Sichuan,China 
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下载免费PDF全文 《大气和海洋科学快报》2016,(2)
降水是由复杂的动力、热力和云微物理过程相互作用产生。为了揭示四川暴雨过程的云微物理特征,利用WRF模式对四川一次暴雨过程的高分辨率模拟资料,研究不同强度降水中云微物理特征和过程的差异。结果显示,水凝物含量在不同强度降水中显著不同;随着降水强度增强,与雨水产生直接或间接相关的云微物理转化过程明显增强;作为雨水的两个主要源项,云水被雨水碰并收集(QCL_(cr))随着降水强度增强而单调递增,而霰融化(QML_(gr))增长较为缓慢。 相似文献
10.
东北冷涡中尺度云系降水机制研究 II: 数值模拟 总被引：1，自引：1，他引：0
在利用卫星、雷达和机载PMS(粒子测量系统)等观测资料对2003年7月8日东北冷涡积层混合云系的降水形成机制分析的基础上,将观测分析与数值模拟研究相结合,用中尺度数值模式对积层混合云系做数值模拟,并结合观测资料进一步分析了积层混合云系的微物理结构、粒子形成过程和降水形成机制,获得如下结果:(1)混合云中对流云具有分层的微物理结构.冰晶含水量最大值出现的高度最高,其次由高到低的排序是雪、云水、霰和雨;雨水主要出现在云的暖区;各种粒子中以雨水含水量最高,其次是霰.对流云体生命期较长,微物理结构基本稳定.(2)粒子形成增长过程有差异.冰晶通过凝华过程增长.雪主要来源于冰晶,产生后主要通过撞冻、收集冰晶和凝华过程增长,其中撞冻过冷云水增长对雪质量贡献最大,其产生率极大值高度与过冷云水相当.丰富的过冷云水,给雪的撞冻增长提供了有利条件.在高、中和低层雪的形成有着不同的机制,高层雪收集冰晶长大后,下落到低层又以雪撞冻过冷云水的结淞增长为主要过程.霰主要由雨滴冻结和雪的转化产生,过冷雨滴与冰晶接触冻结成霰;过冷雨滴收集雪,雪随着雨滴的冻结而转化成霰.因此霰的产生与过冷雨滴关系极大.霰主要撞冻云水、收集雪和冰晶增长,其中撞冻是霰的重要增长过程.雨水主要由霰的融化形成,降水主要是由冷云过程产生的.在过冷层,霰撞冻增长占优势.云上部的冰晶和雪对云的中部具有播撒作用,过冷层中存在丰富的过冷水,对冰相粒子的撞冻增长有利.对云水消耗的分析表明,雨滴对云滴的收集、霰和雪对云水的撞冻增长是消耗云水的主要过程.(3)从各种粒子的形成和增长过程可以看出,大部分雨水由霰融化形成,暖云过程贡献要小得多.可见,降水主要是由冷云过程产生的,这与观测分析的结果一致. 相似文献
11.
A Simulation Study on the Characteristics of Cloud Microphysics of
Heavy Rainfall in the Meiyu Front 下载免费PDF全文
下载免费PDF全文 A heavy rainfall in the Meiyu front during 4--5 July 2003 is simulated by use of the non-hydrostatic mesoscale model MM5 (V3--6) with different explicit cloud microphysical parameterization schemes. The characteristics of microphysical process of convective cloud are studied by the model outputs. The
simulation study reveals that: (1) The mesoscale model MM5 with explicit cloud microphysical process is capable of simulating the instant heavy rainfall in the Meiyu front, the rainfall simulation
could be improved significantly as the model resolution is increased, and the Goddard scheme is better than the Reisner or Schultz scheme. (2) The convective cloud in the Meiyu front has a
comprehensive structure composed of solid, liquid and vapor phases of water, the mass density of water vapor is the largest one in the cloud; the next one is graupel, while those of ice, snow, rain
water and the cloud water are almost same. The height at which mass density peaks for different hydrometeors is almost unchangeable during the heavy rainfall period. The mass density variation of rain water, ice, and graupel are consistent with that of ground precipitation, while that of water vapor in the low levels is 1--2 h earlier than the precipitation. (3) The main contribution to the water vapor budget in the atmosphere is the convergence of vapor flux through advection and convection, which provides the main vapor source of the rainfall. Besides the basic process of the auto-conversion of cloud water to rain water, there is an additional cloud microphysical process that is essential to the formation of instant heavy rainfall, the ice-phase crystals are transformed into graupels first and then the increased graupels mix with cloud water and accelerates the conversion of cloud water to rain water. The positive feedback mechanism between latent heat release and convection is the main cause to maintain and develop the heavy precipitation. 相似文献
12.
W. S. Lin C.-H. Sui C. Bueh A. Wang S. Fan C. Wu S. Fong J. Li J. Meng 《Meteorology and Atmospheric Physics》2007,95(3-4):195-204
Summary A moderate snowfall event in North China is simulated using the high-resolution mesoscale model MM5. A fourfold-nest experiment,
with a minimum horizontal grid size of 2 km, is run. In order to study the cloud microphysics processes associated with the
snowfall, two experiments were conducted in two inner domains, one using the Goddard scheme (Goddard experiment), and the
other using the Reisner scheme (Reisner experiment). The analysis focused on the comparison of the cloud microphysics processes
which occurred in the experiments.
It is shown that there is no implicit precipitation of cumulus parameterization in the domain of grid scale 18 km. The snowfall
distribution patterns in the experiments are slightly different, but the microphysical characteristics and processes may have
considerable differences between the two experiments: (1) The water substances in the cloud have cloud water, cloud ice and
snow, but no rainwater and graupel in the Goddard experiment. However, the water substances in the cloud have cloud ice, snow,
and graupel, but no cloud water and rainwater in the Reisner experiment. (2) The cloud ice mixing ratios in the Goddard experiment
are larger than those in the Reisner experiment. (3) In the Goddard experiment, the dominant cloud microphysical processes
include the growth of cloud water by the condensation of supersaturated vapor, the depositional growth of cloud ice, the initiation
of cloud ice, the accretion of cloud ice by snow, the accretion of cloud water by snow, the deposition growth of snow and
the Bergeron process of cloud ice. In the Reisner experiment, the dominant cloud microphysical processes include the depositional
growth of cloud ice, the conversion of cloud ice to snow, the deposition of snow, and the deposition growth of graupel. (4)
There is only snowfall in the Goddard experiment. Meanwhile, there is ice fall, snow fall, and graupel in the Reisner experiment.
But the ice fall and graupel in the Reisner experiment is very slight and can be ignored. 相似文献
13.
利用GRAPES模式研究气溶胶对云和降水过程的影响 总被引：5，自引：3，他引：2
在GRAPES中尺度模式的双参数微物理方案中加入了气溶胶活化参数化过程,实现了对云滴数浓度的预报。选取不同季节两个降水过程进行模拟,并分别开展了不同气溶胶背景下的两个试验进行对比分析,研究气溶胶对云和降水可能的影响。结果表明:气溶胶浓度增加后,因为活化产生了更多尺度较小的云滴,抑制了云雨的自动转化,使大气中滞留了更多的云水,暖云降水减小;另一方面,云水的增加会使冰相粒子,尤其是雪和霰通过碰并云水等过程而增大,最后融化成雨增加冷云降水,同时冰相粒子增加会释放更多的潜热,促进上升气流的发展,进一步增加冷云降水。气溶胶对降水的影响存在空间不一致性,暖云较厚的地方暖雨过程受到的抑制明显,使地面降水减小,冷云厚度相对较厚时,冷云降水的增加会大于暖云降水的抑制,使地面降水增加。同时由于在云降水发展的不同阶段冷暖云的变化,气溶胶对降水的影响也存在着时间不一致性。 相似文献
14.
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
15.
A Simulating Study on Resolvable-Scale Microphysical Parameterization in a Mesoscale Model 总被引：3，自引：1，他引：2
The Penn State/ NCAR Mesoscale Model (MM5) is used to simulate the precipitation event that oc-curred during 1-2 May 1994 to the south of the Yangtze River. In five experiments the Kain-Fritsch scheme is made use of for the subgrid-scale convective precipitation, but five different resolvable-scale microphysical parameterization schemes are employed. They are the simple super-saturation removal scheme, the warm rain scheme of Hsie et al. (1984), the simple ice scheme of Dudhia (1989), the complex mixed-phase scheme developed by Reisner et al. (1993). and the GSFC microphysical scheme with graupel. Our interest is how the various resolvable-scale schemes affect the domain-averaged precipitation, the pre-cipitation distribution, the sea level pressure, the cloud water and the cloud ice.Through a series of experiments about a warm sector rainfall case, results show that although the dif-ferent resolvable-scale scheme is used, the differences of the precipitation characteristics among all five runs are not very obvious. However, the precipitation is over-predicted and the strong mesoscale low is produced by the simple super-saturation removal scheme. The warm rain scheme with the inclusion of condensation and evaporation under-predicts the precipitation and allows the cloud water to reach the 300 hPa level The scheme of the addition of graupel increases the resolvable-scale precipitation by about 20%–30%. The inclusion of supercooled liquid water in the grid-scale scheme does not affect significantly the results. 相似文献
16.
运用中尺度WRF模式,分别采用Morrison(MOR)和Milbrandt-Yau(MY)双参数化云微物理方案,对2010年7月20—21日辽宁省的一次强降水过程进行模拟,通过对比分析两个方案所对应的地表累积降水量、降水强度、云中微物理量的模拟结果,评估两个双参数方案对强降水事件的模拟能力及主要微物理过程的差异。结果表明,在对雨带和强降水中心的位置上,MOR方案的模拟能力优于MY方案,但MY方案对强降水中心强度模拟能力则优于MOR方案;两方案对强降水宏观特征的模拟差异在一定程度上体现了它们在微物理具体方案上的差异,相比MY方案而言,MOR方案模拟降水发展期的垂直水汽通量高,使得雪晶的凝华增长、碰连增长增强,从而导致MOR方案的冰晶含量低,雪晶含量高,通过雪晶的凇附作用形成的霰含量也比MY方案高,霰的凇附增长消耗了大量过冷水,使冷云中云滴(过冷水)含量减少; MOR方案模拟得到的600 hPa到地表的雨滴直径均为1 mm,与实际雨滴直径的观测值不符,需要未来进一步开展研究,对原方案进行优化。 相似文献