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1.
基于WRF(Weather Research and Forecasting)模式及其3Dvar(3-Dimentional Variational)资料同化系统,采用36、12、4 km嵌套网格进行快速更新循环同化和不同的微物理及积云对流参数化方案对比试验,对2011年5月8日鲁中一次局地大暴雨过程进行了研究。结果表明,快速更新循环同化地面观测资料是影响模式降水落区预报准确性的关键因素,不同的微物理和积云对流参数化方案主要影响降水强度预报。采用不同的微物理参数化方案和积云对流参数化方案进行降水预报对比试验表明,LIN方案和WSM6(WRF Single-Moment 6-class)微物理参数化方案对降水预报均较好,LIN方案降水预报较WSM6方案略强。4 km网格预报使用K-F (Kain-Fritsch)积云对流参数化方案或不使用积云对流参数化方案,预报的降水均较好。4 km网格使用旧的K-F积云对流参数化方案,预报的近地层大气风场偏弱,导致大气动力抬升作用偏弱,从而造成模式降水预报偏弱。 相似文献
2.
高分辨率模式中积云参数化方案对模拟台风“凡亚比”的影响 总被引：1，自引：0，他引：1
在高水平分辨率模式(3～6 km)中,对于是否应该再使用积云参数化方案,仍存在着争论.为此,利用WRF模式,在5 km水平分辨率下,研究了不同云降水方案对一次台风过程模拟的影响,并对影响原因进行了初步探索.结果表明,即使在5 km高水平分辨率下,使用积云参数化方案仍能有效改善对台风路径的模拟,同时,成熟的混合冰相微物理方案对模拟台风路径也非常重要;对台风强度模拟,对积云参数化方案的选择较为敏感和复杂;在48 h预报时效内,只使用微物理方案模拟的降水较好,使用积云参数化方案容易产生较多的虚假降水,但能改善第3天24 h累积降水模拟.这些研究结果为利用高水平分辨率模式模拟台风和改进积云参数化方案提供一定借鉴. 相似文献
3.
Jamaludin Suhaila S. M. Deni Wan Zawiah Wan Zin Abdul Aziz Jemain 《Meteorology and Atmospheric Physics》2010,106(1-2):1-18
Model precipitation can be produced implicitly through convective parameterization schemes or explicitly through cloud microphysics schemes. These two precipitation production schemes control the spatial and temporal distribution of precipitation and consequently can yield distinct vertical profiles of heating and moistening in the atmosphere. The partition between implicit and explicit precipitation can be different as the model changes resolutions. Within the range of mesoscale resolutions (about 20 km) and cumulus scale, hybrid solutions are suggested, in which cumulus convection parameterization is acting together with the explicit form of representation. In this work, it is proposed that, as resolution increases, the convective scheme should convert less condensed water into precipitation. Part of the condensed water is made available to the cloud microphysics scheme and another part evaporates. At grid sizes smaller than 3 km, the convective scheme is still active in removing convective instability, but precipitation is produced by cloud microphysics. The Eta model version using KF cumulus parameterization was applied in this study. To evaluate the quantitative precipitation forecast, the Eta model with the KF scheme was used to simulate precipitation associated with the South Atlantic Convergence Zone (SACZ) and Cold Front (CF) events. Integrations with increasing horizontal resolutions were carried out for up to 5 days for the SACZ cases and up to 2 days for the CF cases. The precipitation partition showed that most of precipitation was generated by the implicit scheme. As the grid size decreased, the implicit precipitation increased and the explicit decreased. However, as model horizontal resolution increases, it is expected that precipitation be represented more explicitly. In the KF scheme, the fraction of liquid water or ice, generated by the scheme, which is converted into rain or snow is controlled by a parameter S 1. An additional parameter was introduced into KF scheme and the parameter acts to evaporate a fraction of liquid water or ice left in the model grid by S 1 and return moisture to the resolved scale. An F parameter was introduced to combine the effects of S 1 and S 2 parameters. The F parameter gives a measure of the conversion of cloud liquid water or ice to convective precipitation. A function dependent on the horizontal resolution was introduced into the KF scheme to influence the implicit and explicit precipitation partition. The explicit precipitation increased with model resolution. This function reduced the positive precipitation bias at all thresholds and for the studied weather systems. With increased horizontal resolution, the maximum precipitation area was better positioned and the total precipitation became closer to observations. Skill scores for all events at different forecast ranges showed precipitation forecast improvement with the inclusion of the function F. 相似文献
4.
不同降水方案对"03.7"一次暴雨过程模拟的影响 总被引：4，自引：0，他引：4
观测和数值模拟研究已经表明,潜热释放对中国东部夏季梅雨锋系统及其锋面降水的维持和发展发挥着非常重要的作用.然而,目前对于梅雨锋降水模拟中各种降水方案的相互协调和系统评估方面的工作仍不多见,为了增进对梅雨锋暴雨模拟中降水过程的认识,作者针对2003年7月4～5日一次梅雨锋暴雨过程,构造了四组试验,利用MM5模式考察了两种分辨率(36 km、12 km),各种隐/显式方案搭配下,对所生成的雨带、雨量和降水类型的配置进行了仔细的研究,得到了一些有意义的结论,为今后更好地使用模式、利用数值模式来认识中尺度降水过程中的气象问题打下基础.主要结论包括:模拟总降水的水平分布和强度,以及显式降水和隐式降水的划分对积云参数化方案的选择非常敏感.但对特定积云参数化方案而言,降水的模拟对36 km、12 km水平分辨率不敏感(除Betts-Miller方案外);在中尺度网格分辨率10～50 km范围内,不同积云参数化方案对梅雨锋降水分布和降水量模拟的影响比不同显式方案带来的变化大得多. 相似文献
5.
Impact of Horizontal Resolution and Cumulus Parameterization Scheme on the Simulation of Heavy Rainfall Events over the Korean Peninsula 总被引：1，自引：0，他引：1
In this paper, we present the results from high-resolution numerical simulations of three heavy rainfall events over the Korean Peninsula. The numerical results show that the prediction accuracy for heavy rainfall events improved as horizontal resolution increased. The fine-grid precipitation fields were much closer to the real precipitation fields in the case of large synoptic forcing over the Korean Peninsula. In the case of large convective available potential energy and weak synoptic forcing, it seems that even when using a high resolution, the models still showed poor performance in reproducing the observed high precipitation amounts. However, activation of the cumulus parameterization scheme in the intermediate resolution of 9 km, even at a grid spacing of 3 km, had a positive impact on the simulation of the heavy rainfall event. 相似文献
6.
A Two-Moment Bulk Microphysics Coupled with a Mesoscale Model WRF: Model Description and First Results 总被引：1，自引：0，他引：1
The Chinese Academy of Meteorological Sciences (CAMS) two-moment bulk microphysics scheme was adopted in this study to investigate the representation of cloud and precipitation processes under different environmental conditions.The scheme predicts the mixing ratio of water vapor as well as the mixing ratios and number concentrations of cloud droplets,rain,ice,snow,and graupel.A new parameterization approach to simulate heterogeneous droplet activation was developed in this scheme.Furthermore,the improved CAMS scheme was coupled with the Weather Research and Forecasting model (WRF v3.1),which made it possible to simulate the microphysics of clouds and precipitation as well as the cloud-aerosol interactions in selected atmospheric condition.The rain event occurring on 27-28 December 2008 in eastern China was simulated using the CAMS scheme and three sophisticated microphysics schemes in the WRF model.Results showed that the simulated 36-h accumulated precipitations were generally agreed with observation data,and the CAMS scheme performed well in the southern area of the nested domain.The radar reflectivity,the averaged precipitation intensity,and the hydrometeor mixing ratios simulated by the CAMS scheme were generally consistent with those from other microphysics schemes.The hydrometeor number concentrations simulated by the CAMS scheme were also close to the experiential values in stratus clouds.The model results suggest that the CAMS scheme performs reasonably well in describing the microphysics of clouds and precipitation in the mesoscale WRF model. 相似文献
7.
Jin-Fang Yin Dong-Hai Wang Zhao-Ming Liang Chong-Jian Liu Guo-Qing Zhai Hong Wang 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(1):77-90
Simulations of the severe precipitation event that occurred in the warm sector over southern China on 08 May 2014 are conducted using the Advanced Weather Research and Forecasting (WRF-ARWv3.5.1) model to investigate the roles of microphysical latent heating and surface heat fluxes during the severe precipitation processes. At first, observations from surface rain gauges and ground-based weather radars are used to evaluate the model outputs. Results show that the spatial distribution of 24-h accumulated precipitation is well reproduced, and the temporal and spatial distributions of the simulated radar reflectivity agree well with the observations. Then, several sensitive simulations are performed with the identical model configurations, except for different options in microphysical latent heating and surface heat fluxes. From the results, one of the significant findings is that the latent heating from warm rain microphysical processes heats the atmosphere in the initial phase of the precipitation and thus convective systems start by self-triggering and self-organizing, despite the fact that the environmental conditions are not favorable to the occurrence of precipitation event at the initial phase. In the case of the severe precipitation event over the warm sector, both warm and ice microphysical processes are active with the ice microphysics processes activated almost two hours later. According to the sensitive results, there is a very weak precipitation without heavy rainfall belt when microphysical latent heating is turned off. In terms of this precipitation event, the warm microphysics processes play significant roles on precipitation intensity, while the ice microphysics processes have effects on the spatial distribution of precipitation. Both surface sensible and latent heating have effects on the precipitation intensity and spatial distribution. By comparison, the surface sensible heating has a strong influence on the spatial distribution of precipitation, and the surface latent heating has only a slight impact on the precipitation intensity. The results indicate that microphysical latent heating might be an important factor for severe precipitation forecast in the warm sector over southern China. Surface sensible heating can have considerable influence on the precipitation spatial distribution and should not be neglected in the case of weak large-scale conditions with abundant water vapor in the warm sector. 相似文献
8.
云物理过程是云和降水形成的重要环节。本文针对2011年6月23日发生在北京地区的一次大暴雨过程进行了云降水与天气特征分析,并开展了WRF模式中10种不同云微物理方案对此次暴雨强度、落区和发生时间的敏感性数值模拟试验。研究结果表明,此次大暴雨是由多单体组织、合并形成深厚的中尺度对流系统,并具有明显的短时局地特征和有利的高低空、高低纬度大中尺度天气环流形势及强烈的水汽输送条件。暴雨强度、落区和发生时间的数值模拟结果对云物理方案非常敏感。不同云物理方案对累积降水量≥50 mm和≥100 mm的暴雨模拟的ETS评分显示,只有Thompson方案对此暴雨量级的评分均为正,其他方案的ETS评分均不理想,特别是对累积降水量≥100 mm的大暴雨模拟。在小时暴雨强度和发生时间方面,Thompson方案模拟效果也较好,其次是Lin方案和WSM6方案;对区域累积最大降水量和落区的模拟方面,Thompson方案和Morrison方案模拟的最大累积降水量更接近观测值,但在落区方面,一些具有完整云物理过程的单参数方案（Lin方案、WSM6方案）模拟效果较好,但模拟的最大降水量偏小。针对暖雨的双参数方案WDM6对区域平均降水模拟较好,但对暴雨极端降水模拟较差。对造成差异的原因分析表明,不同云物理方案的差异主要体现在雪和霰的参数化方面,由于采用的粒子谱分布、密度和末速度不同,导致云中粒子间的碰并和形成过程不同,大部分云物理方案模拟的霰含量高,雪含量低。这种云微物理过程的差异会导致云动力过程的反馈作用出现明显不同,但这种反馈作用的差异主要体现在降水粒子对上升气流的拖曳作用不同。尽管云中相变潜热过程对云动力过程具有很重要的影响,但不同云物理方案在相变潜热过程和温度廓线分布方面造成的差异并不明显。因此,云物理方案中考虑合理的粒子谱分布、形态和密度变化,有利于提高暴雨的模拟效果。 相似文献
9.
地基微波辐射计资料的等值线自动绘制方法 总被引：1，自引：0，他引：1
利用美国国家大气研究中心（National Center for Atmospheric Research,NCAR）中尺度模式（WRF-ARW）以及美国国家海洋和大气管理局（NOAA）三维变分同化系统GSI（Gridpoint StatisticalInterpolation）,对2005年6月20-21日发生在广东省中部的一场致洪暴雨进行了模拟。与雨量计观测的和卫星反演的降水混合资料相比,模式能够成功地模拟出降水的位置和强度。但数值模拟的效果很大程度上取决于3个条件：模式分辨率;物理过程方案;初始条件。在此次暴雨的模拟中,采用Eta Ferrier微物理方案、内层区域4km细分辨率与外层区域12km粗分辨率组成双层嵌套网格和卫星辐射资料同化的初始化方案是非常合适的。 相似文献
10.
WRF模式对青藏高原南坡夏季降水的模拟分析 总被引：2，自引：0，他引：2
利用中尺度数值模式WRF研究积云对流参数化方案、网格嵌套技术和模式分辨率对陡峭的青藏高原南坡夏季降水模拟的影响。对2006年7月青藏高原南坡地区降水的模拟分析表明:降水对积云对流参数化方案的选择很敏感,不同方案模拟的结果差异显著,采用Grell-Devenyi质量通量方案时的模拟效果优于其他方案。在此基础上,通过5种试验方案比较发现,使用积云对流参数化方案、提高模式分辨率和应用网格嵌套技术能改善降水强度和空间分布的模拟,组合使用时模拟的降水与观测资料更接近。它们均能改进风场,使得水汽的输送和辐合过程的模拟更加准确;还能影响大气的垂直加热状态,导致不同的对流发生,使垂直速度的分布趋于合理。未使用积云对流参数化方案时,大气湿度偏小,而模式分辨率和网格嵌套技术对大气湿度的影响不大。 相似文献
11.
袁招洪 《Acta Meteorologica Sinica》2015,73(4):648-666
为研究不同分辨率和微物理方案对飑线阵风锋模拟的影响,利用WRF中尺度数值预报模式,对2009年6月5日发生在上海的一次飑线过程分别进行了3、1、0.5 km水平分辨率和一、二阶矩微物理方案的理想试验。结果表明,模式水平分辨率和微物理方案对模拟飑线阵风锋有明显的影响。随模式水平分辨率的提高,模式模拟的飑线弓状回波结构更精细。与3 km分辨率相比,1和0.5 km分辨率模式能很好模拟出飑线后部下沉气流和前部上升气流,模拟的冷池前沿最大风速相对更接近实况。二阶矩微物理方案更能模拟出飑线弓状回波前强后弱的结构特征和飑线过境地面降温幅度,模拟的飑线移动速度、冷池面积和强度、冷池前沿最大风速和雨水蒸发率等均小于一阶矩微物理方案的模拟值。采用1和0.5 km模式水平分辨率及二阶矩微物理方案模式模拟的飑线与WSR-88D多普勒天气雷达探测实况更接近。模式分辨率的提高有利于模拟飑线的维持。对业务数值预报模式模拟飑线阵风锋而言,在计算条件允许的情况下,模式水平分辨率达1 km并采用二阶矩微物理方案可能是需要的。结果还表明,冷池前沿最大风速、冷池强度、模式底层降温幅度、飑线移动速度与雨水蒸发率存在对应的变化趋势,飑线移动速度的变化对飑线阵风锋地面大风的预报有指示意义。改善数值模式对飑线阵风锋预报性能除需关注模式水平分辨率和微物理方案外,还需关注数值模式对雨水蒸发率的模拟能力。 相似文献
12.
中尺度降水模式预报具有很大的不确定性,为更好地描述与模式降水预报密切相关的物理过程关键参数的不确定性,基于中国气象局GRAPES（Global/Regional Assimilation and Prediction System）中尺度区域集合预报模式,从对模式降水预报不确定性有较大影响的积云对流、云微物理、边界层及近地面层等4个参数化方案中选取了18个关键参数,设计了一种随机参数扰动方案（Stochastically Perturbed Parameterization,SPP）,并通过2015年6—7月总计10 d的随机扰动集合预报试验,对比分析了SPP方案对不同物理过程参数扰动敏感性、随机场时、空尺度敏感性、能量变化特征及其集合预报效果。结果显示,对所选择的任一物理过程参数化方案增加SPP扰动后,降水及等压面要素的概率预报技巧优于无SPP扰动的预报,而扰动积云对流和边界层过程中的参数较扰动云微物理过程中的参数影响更显著,且同时扰动积云对流、云微物理、边界层及近地面层参数化方案中的18个参数的集合预报效果优于扰动任何单一物理过程中的部分参数,表明SPP方案能够有效地提高中尺度降水概率预报技巧;从能量变化特征可知,不同物理过程的参数扰动对动能、内能和总能量的影响层次和特征有所不同,但总体而言,扰动前后各项能量基本相同;随机场时、空尺度敏感性试验发现,SPP扰动随机场时间、空间相关尺度对集合预报效果有明显影响,当扰动随机场选用12 h抗相关时间及截断波数20时,集合预报结果最优。上述结果表明,SPP随机参数扰动方案不仅能够有效提高集合概率预报效果,还能够提高集合降水概率预报技巧,具有良好的业务应用与发展前景。 相似文献
13.
为评估2014年南京青奥会开幕式日的人工催化消减雨作业效果,利用中尺度数值模式WRF对当日的云降水过程和催化作业开展数值模拟。本文系第一部分工作。首先对常用的八种云微物理方案的降水模拟效果进行评估,进一步选取Thompson和Milbrandt-Yau两个微物理方案对此次降水过程的云系结构和降水形成机制进行对比分析。模拟结果表明,采用Thompson和Milbrandt-Yau两个方案模拟的云系结构和降水形成的微物理机制是一致的。开幕式当天影响奥体场馆的降水由弱的积层混合云系产生,降水过程以冰相微物理过程为主。雪的融化是雨水的主要源项,Thompson方案中雪的融化对雨水的贡献率为72%,Milbrandt-Yau方案为60%,蒸发则是雨水的主要汇项,Thompson方案中蒸发对雨水的消耗率达94%,Milbrandt-Yau方案为95.6%。 相似文献
14.
The understanding of the cloud processes of snowfall is essential to the artificial enhancement of snow and the numerical simulation of snowfall. The mesoscale model MM5 is used to simulate a moderate snowfall event in North China that occurred during 20–21 December 2002. Thirteen experiments are performed to test the sensitivity of the simulation to the cloud physics with different cumulus parameterization schemes and different options for the Goddard cloud microphysics parameterization schemes. It is shown that the cumulus parameterization scheme has little to do with the simulation result. The results also show that there are only four classes of water substances, namely the cloud water, cloud ice, snow, and vapor, in the simulation of the moderate snowfall event. The analysis of the cloud microphysics budgets in the explicit experiment shows that 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 are the dominant cloud microphysical processes in the simulation. The accretion of cloud water by snow and the deposition growth of the snow are equally important in the development of the snow. 相似文献
15.
模式的不同参数化方案会对模拟的天气和气候产生影响,但如何影响陆气耦合还不是很清楚。利用WRF 4.0模式设计了一组16种不同参数化方案组合的集合试验,对华北地区2013年夏季气候进行模拟。结果表明,不同积云对流参数化方案对模拟的降水平均态影响较大,其次是短波辐射方案,而微物理方案影响较小。进一步利用潜热通量(LH,Latent Heat flux)和土壤湿度(SM,Soil Moisture)、抬升凝结高度(LCL,Lifting Condensation Level)的相关系数R(SM,LH)和R(LH,LCL)表征陆气耦合过程,评估了陆气耦合对不同参数化方案的敏感性。模式模拟的R(SM,LH)在不同区域随着平均降水、相对湿度的增加以及平均短波辐射的减少而减小,而R(LH,LCL)的变化正好相反。它们内在的物理机制类似,与气候态的干湿变化密切相关,即随着土壤湿度趋于饱和,蒸散发过程逐渐受太阳辐射的限制,陆面对大气的影响减弱。另外,陆气耦合强度受积云对流方案、微物理方案和短波辐射方案的影响而产生差别,这与不同参数化方案模拟的气候态的不同密切相关,因此本研究对于WRF 4.0模式中参数化方案特别是积云对流方案的选择同样有着重要的指导意义。 相似文献
16.
Improvements in WRF simulation skills of southeastern United States summer rainfall: physical parameterization and horizontal resolution 总被引：2，自引：0，他引：2
Realistic regional climate simulations are important in understanding the mechanisms of summer rainfall in the southeastern United States (SE US) and in making seasonal predictions. In this study, skills of SE US summer rainfall simulation at a 15-km resolution are evaluated using the weather research and forecasting (WRF) model driven by climate forecast system reanalysis data. Influences of parameterization schemes and model resolution on the rainfall are investigated. It is shown that the WRF simulations for SE US summer rainfall are most sensitive to cumulus schemes, moderately sensitive to planetary boundary layer schemes, and less sensitive to microphysics schemes. Among five WRF cumulus schemes analyzed in this study, the Zhang–McFarlane scheme outperforms the other four. Further analysis suggests that the superior performance of the Zhang–McFarlane scheme is attributable primarily to its capability of representing rainfall-triggering processes over the SE US, especially the positive relationship between convective available potential energy and rainfall. In addition, simulated rainfall using the Zhang–McFarlane scheme at the 15-km resolution is compared with that at a 3-km convection-permitting resolution without cumulus scheme to test whether the increased horizontal resolution can further improve the SE US rainfall simulation. Results indicate that the simulations at the 3-km resolution do not show obvious advantages over those at the 15-km resolution with the Zhang–McFarlane scheme. In conclusion, our study suggests that in order to obtain a satisfactory simulation of SE US summer rainfall, choosing a cumulus scheme that can realistically represent the convective rainfall triggering mechanism may be more effective than solely increasing model resolution. 相似文献
17.
Sonia Jerez Juan Pedro Montavez Pedro Jimenez-Guerrero Juan Jose Gomez-Navarro Raquel Lorente-Plazas Eduardo Zorita 《Climate Dynamics》2013,40(11-12):3023-3046
This work assesses the influence of the model physics in present-day regional climate simulations. It is based on a multi-phyiscs ensemble of 30-year long MM5 hindcasted simulations performed over a complex and climatically heterogeneous domain as the Iberian Peninsula. The ensemble consists of eight members that results from combining different parametrization schemes for modeling the Planetary Boundary Layer, the cumulus and the microphysics processes. The analysis is made at the seasonal time scale and focuses on mean values and interannual variability of temperature and precipitation. The objectives are (1) to evaluate and characterize differences among the simulations attributable to changes in the physical options of the regional model, and (2) to identify the most suitable parametrization schemes and understand the underlying mechanisms causing that some schemes perform better than others. The results confirm the paramount importance of the model physics, showing that the spread among the various simulations is of comparable magnitude to the spread obtained in similar multi-model ensembles. This suggests that most of the spread obtained in multi-model ensembles could be attributable to the different physical configurations employed in the various models. Second, we obtain that no single ensemble member outperforms the others in every situation. Nevertheless, some particular schemes display a better performance. On the one hand, the non-local MRF PBL scheme reduces the cold bias of the simulations throughout the year compared to the local Eta model. The reason is that the former simulates deeper mixing layers. On the other hand, the Grell parametrization scheme for cumulus produces smaller amount of precipitation in the summer season compared to the more complex Kain-Fritsch scheme by reducing the overestimation in the simulated frequency of the convective precipitation events. Consequently, the interannual variability of precipitation (temperature) diminishes (increases), which implies a better agreement with the observations in both cases. Although these features improve in general the accuracy of the simulations, controversial nuances are also highlighted. 相似文献
18.
The impact of cumulus parameterizations and microphysics schemes under different combinations on typhoon track prediction 总被引：2，自引：1，他引：1
This study examines the effects of cumulus parameterizations and microphysics schemes on the track forecast of typhoon Nabi using the Weather Research Forecast model. The study found that the effects of cumulus parameterizations on typhoon track forecast were comparatively strong and the typhoon track forecast of Kain-Fritsch (KF) was superior to that of Betts-Miller (BM). When KF was selected, the simulated results would be improved if microphysics schemes were selected than otherwise. The results from Ferrier, WSM6, and Lin were very close to those in the best track. KF performed well with the simulations of the western extension and eastern contraction changes of a North Pacific high as well as the distribution and strength of the typhoon wind field. 相似文献
19.
WRF模式中的微物理过程及其预报对比试验 总被引：7，自引：0，他引：7
WRF(Weather Research Forecast)模式系统是由许多美国研究部门及大学的科学家共同参与进行开发研究的新一代中尺度同化预报系统。本文主要对公开发布的WRF模式V2.0版本中使用的微物理过程方案进行简单介绍,并在国家气象中心建立的与T213中期预报模式相嵌套的预报系统的基础上,对不同微物理过程方案进行了降水预报对比试验和检验,对各方案的降水预报性能进行初步评估。试验结果表明,总体预报效果LIN方案较好,而对流参数化方案从降水落区预报和对流降水对总降水的贡献两方面看则是KF和NKF方案的预报效果较好。 相似文献
20.
MM5模式中不同对流参数化方案的比较试验 总被引：58，自引：2，他引：58
应用MM5中尺度模式, 在60、20和10 km模式分辨率下, 分别选用4种不同对流参数化方案 (KUO方案、GRELL方案、KAIN-FRITSCH方案和BETTS-MILLER方案, 以下简称KU、GR、KF和BM方案) 对1996年8月3~4日石家庄暴雨过程进行数值模拟试验.模拟结果的对比分析及其与观测的比较表明:主要雨带位置对参数化方案并不是十分敏感, 但随分辨率提高, 雨带分布特征的模拟更接近实况; 当分辨率提高到10 km时, 虚假的降水中心也明显增加; 模拟的暴雨中心强度随分辨率的提高而增强并随参数化方案的不同有所变化, 但均比实况偏弱.分析还发现, MM5模式的GR、KF及BM方案的次网格降水对总降水的贡献率随分辨率的提高而减小, 而KU方案的情况则呈现出不合理的缓慢增加态势.虽然4种方案下模拟的水平环流特征有较好的一致性, 但模拟的云物理特征和垂直运动特征还是存在一定差别的, 这种差别对定点、定量降水和天空状况、地面气温、湿度等要素的准确预报都会产生影响.因此, 在预报和模拟中应考虑预报和研究对象的特点来选择对流参数化方案. 相似文献