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。
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 little 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 accurate results of the short range precipitation system.
出处
《气象学报》
CSCD
北大核心
1997年第5期573-587,共15页
Acta Meteorologica Sinica
基金
国家"八五"攻关
国家自然科学基金
