包含正定水汽输送算法改进的MM4中尺度模式与暴雨实例数值试验
A MESOSCALE MODEL INCLUDING POSITIVE WATER TRANSPORT ALGORITHMS AND NUMERICAL EXPERIMENT
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摘要: 暴雨预报是一个既重要又十分困难的问题。水汽条件是产生暴雨的关键,水汽的平流输送在模式的水汽方程中占有重要地位,模式对暴雨的预报能力必然涉及到水汽输送的计算精度问题;本文以著名的中尺度模式MM4为基础,理论测试和分析为依据,以引入新的正定高精度水汽输送算法作为消除模式水汽负值和改进中尺度模式预报能力的途径,研制了取名为改进的MM4中尺度模式,该模式除仍保留原MM4模式的所有功能外,增加了5种水汽输送算法的改进与选择,这5种算法是:1)B网格二阶守恒中心差(原MM4平流格式),2)上游差分,3)Bot(2阶),4)Bot(4阶),5)Prather格式。多个暴雨、台风个例试验表明模式预报能力对水汽输送算法精度有显著的依赖性,采用高精度的水汽输送算法水汽保证正值并提高了模式对暴雨区、降水结构、雨团活动的预报能力。改进水汽输送算法的精度是提高中尺度模式对暴雨预报能力的重要途径。Abstract: It is a very important and difficult problem for prediction heavy rain. The moisture transport plays important role in modeling the mesoscale weather process. Based on mesoscale model MM4, by cooperating with some more accurate water transport schemes, a mesoscale numerical weather prediction system NMM is developed. These schemes include: (1) B-grid Center Conservative Scheme which is used in MM4; (2) Bott (2-order) Scheme;(3) Bott (4-order) Scheme; (4) Upstream Scheme; (5) Prather Scheme. Bott Scheme and Prather Scheme Both Schemes are positive and produces a lit tle numerical diffusion and computation dispersion. Numerical experimete of move heavy rain process under the model water transport algorithm's options of B-grid Center Scheme, Upstream scheme and Prather Scheme shown the high accurate water transport algorithms, just like Prather scheme improving the precipitation prediction of the mesoscale model and giving more accur ate results of the short range precipitation system.
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Keywords:
- Mesoscale model /
- Moisture transport /
- Transport scheme
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Anthes R A and Warner T T. Development of hydrodynamic models suitable for air pollution and other mesometeoro logical studies. Mon Wea Rev, 1978, 106(8): 1045-1077.
[2] Smolarkiewicz P K. The multidim ensional crowley advection scheme. Mon Wea Rev, 1982, 110 (12): 1968-1983.
[3] Prather M J. Numerical advection by conservation of second-order moments. J Geephy Res, 1986, 91(4): 6671-6681.
[4] Bott A. Apositive definete advection scheme obtained by nonlinear renormalization of the advective fluxes. Mon Wea Rev. 1989, 117(5): 1006-1015.
[5] Lei Xiaoen and Chang J S. A high resolution model for chimicals pecies exchange within the tropos phere. Acta Meteor Sinica, 1992, 6: 479-490.
葛孝贞, Chang J S, 雷孝恩. 高分辨区域输送模式中不同输送格式的对比试验. 大气科学. 1996, 20(1): 37-46. [7] 葛孝贞, 沈岩. 弱引导气流下凝结加热与台风异常运动的个例试验. 南京大学学报, 1996, 32: 216-223. [8] 沈岩, 葛孝贞. 不同精度的水汽平流输送格式对台风运动影响的数值试验. 南京大学学报, 1996, 32: 216-223. 史历, 葛孝贞. 一个异常路径台风(8211)非对称结构的数值模拟. 南京大学学报地理专辑, 1996, (5): 95-98. [10] Tremback C J, Powell J, Cotton W R and Pielke R A. The forw ard-in-time upstream advection scheme, extension to higher orders. Mon Wea Rev. 1987, 115: 540-555.
Bleck R. Linear advection. Programme on Short and Medium-range Weather Prediction Research(PSMP),WMO, 1984. 110-115.
[12] 葛孝贞, 李峰. 改进的MM4模式暴雨实例对比试验, 气象科学, 1996(2): 103-109.
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