全球(Z)双三次数值模式的设计与个例模拟(I):模式动力框架设计  

Design of Global(Z) Bicubic Numerical Model(BiNM) and Its Case Simulation(I): Dynamic Framework of Model

作　　者：辜旭赞[1] 张兵[1] 

机构地区：[1]中国气象局武汉暴雨研究所,湖北武汉430074

出　　处：《高原气象》2008年第3期474-480,共7页Plateau Meteorology

基　　金：国家自然科学基金项目(40575053);湖北省科技攻关计划课题(2005AA308B01)共同资助

摘　　要：引入双三次数值模式:双三次数值模式是通过作三次样条与双三次曲面拟合,实现各个大气要素量场的二阶可导,从而可对各个预报方程作时间积分。双三次数值模式适合采用大气运动原始方程组和采用水平方向准拉格朗日/垂直方向欧拉时间积分方案。且本文的全球(Z)双三次数值模式与个例模拟实际采用Navier-Stokes"浅薄大气"原始方程组,建立球面Z坐标系上的非静力、全可压、干/湿绝热大气运动动力框架。其离散化气压、气温预报方程与个例模拟揭示出大气运动中凝结降水,其天气学原因不仅是湿空气作Z坐标垂直上升运动,而且是湿空气被"减压/减温",即湿空气作P坐标"垂直上升运动",后者可由大气平流运动(如Rossby波)引起。Introducing Bicubic Numerical Model （BiNM, shortly）, that has all the advantages of mited difference model as well as the basic advantages of spectrum model, it is with the fitting of cubic curved spline/bicubic curved surface to the discrete mesh, physical fields of the model atmosphere, and getting their second-order derivatives, and doing time integration for the forecast governing equations. BiNM can use Navier-Stokes primitive equation set, but, we adopt an assumption of static equilibrium to ＂diagnostic atmosphere＂ but of non-static equilibrium to ＂motion atmosphere＂, to get perpendicular speed in the vertical equation; and do other assumption of incompressible air for ＂diagnostic atmosphere＂ but of compressible air for ＂motion atmosphere＂, so that acoustic wave should be eliminated in the model atmosphere. So, BiNM has a governing equation set in the spherical coordinate, that is, BiNM＇s dynamic framework of nonstatic, holo-compressible, and dry/wet adiabatic model atmosphere may be set up. Actually, the global - BiNM in the Z coordinate with its simulation cases in this paper use the Navier-Stokes primitive equations of so called ＂shallow atmosphere＂, and adopt the explicit semi-Lagrangian time integration scheme in horizontal direction but Euler time integration scheme in vertical direction because of the gravitation. BiNM＇s discrete pressure and temperature predictive equations as well as its cases show that, for the condensation and precipitation in the model atmosphere, the synoptic reason not only is the wet air making vertical movement in the Z--coordinates, moreover is the wet air being reduced by pressure and temperature, that does the ＂vertical movement＂ in the P--coordinates, latter may be caused by the atmospheric advection motion （for example, the Rossby wave）.

关 键 词：双三次数值模式 原始方程组 非静力全可压大气运动动力框架 准拉格朗日/欧拉时间积分方案 大气运动降水物理机制 

分 类 号：P456.7[天文地球—大气科学及气象学]