【摘要】 利用改进型ＰＳＵ／ＮＣＡＲ中尺度数值模式（ＭＭ４标准版），取模式水平格距４０ｋｍ，４６×６１网格，垂直方向ａ取１５层，即从地面到模式顶（１００ｈＰａ），σ＝０．０、０．１、０．２、０．３、０．４、０．５、０．６、０．７、０．７８、０．８４、０．８９、０．９３、０．９６、０．９８、０．９９、１．００，采用ＮＣＡＲ的３０＇×３０＇地形资料，以常规观测资料作为初始场，较好地模拟了此次沙尘暴过程的海平面气压的演变和分布，特别是张掖、柴达本盆地以及敦煌附近的三个中低压。同时，模拟了张掖中低压与蒙古冷高压之间的甘肃河西沙尘暴东大风。敏感性试验表明，沙尘暴中低压的形成发展主要是受于物理过程制约；沙尘暴中尺度系统的研究与暴雨中尺度系统的研究是有区别的，积云对流参数化并不是特别重要，在设计研究沙尘暴的数值模式中，应当合理地处理其他的热力、动力过程及大气外强迫源的作用。模式水平格距、地形真实程度对模拟中低压的位置、中心强度有重要贡献；下垫面变化中低压强度有一定影响。张掖热低压的形成发展主要是在有利的环境形势下，特殊地势起了重要作用，表现为直接动力强迫和间接热力强迫。更多还原

【Abstract】 Using PSU/NCAR mesoscale numerical model (MM4 standard model), taking 40 kmhorizontal grid spacing, 46 latitude and 61 longtitude dot grid points, and 15 vertical sigma levels withδ=0. 0, 0. 1, 0. 2, 0. 3, 0. 4, 0. 5, 0. 6, 0. 7, 0. 78, 0. 84, 0. 89,0. 93,.0. 96,0. 98, 0. 99 and 1. 0,from model top(100hpa) to it’s bottom, we simulated successfully the evolution and distribution of theduststorm process’ sea-level pressure system, especially three middle-lower pressures in Zhangye,Qaidam basin and near Dunghuang through using MCAR 30 × 30 topographic data and regularobservatoinal data as initial fields. Simultaneously, we simulated Guansu Hexi duststorm pressure.Sensitivity test demonstrated that duststorm’s formation and development is mainly constrained by dryphysical process. The research of duststorm mesoscale systems is different from that of rainstormmesoscale systems, so that cumulus parameterization is not especially important. Attention should bepaid to deal with other factors, dynamic process and functions exerted by atmospheric exteral force induststorm numerical model design and research. The modeds horizontal grid spacing and topographictruth contribute greatly to middle - lower pressure position and central intensity simulation. Thechange of undrelying surface has a certain effect on middle -lower pressure.Under the favourable circulation situation, the formation and development of thermal lowerpressure in Zhangye, especially topographic structure play an important role in immediate dynamicforcing.更多还原