廖洞贤,陆维松. 1982. 有限区域预报中的一些问题[J]. 气象学报, 40(4):387-397, doi:10.11676/qxxb1982.043
有限区域预报中的一些问题
SOME PROBLEMS IN REGIONAL NUMERICAL WEATHER PREDICTION
投稿时间:1980-10-08  修订日期:1981-03-20
DOI:10.11676/qxxb1982.043
中文关键词:  
英文关键词:
基金项目:
作者单位
廖洞贤 中央气象局气象科学研究院 
陆维松 南京气象学院 
摘要点击次数: 1903
全文下载次数: 1824
中文摘要:
      文中首先讨论了在固定边界条件和半固定边界条件下,采用平流方程和浅水波方程计算时引起的误差;给出了误差方程和解析解答.结果证明,在固定边界条件下,采用平流方程时误差以风速从边界向中央传播.在流入处附近,误差使波变平;在流出处附近,波幅增大,波变窄.而采用浅水波方程时,误差则以速度|u+c|和|u-c|从边界向内传播.可是,在半固定边界条件下,采用平流方程时误差却只以风速沿气流方向传播,没有波的叠加所引起的波幅增大现象.根据上述结果,作者提出了,在半固定边界条件下,适于平流方程的逆风差分格式,还对格式的计算稳定性进行了讨论.最后,用这格式作了一维套网格的单向和双向方法的个例计算,并和用蛙跃格式和欧拉向后差格式的结果比较.结果发现,修正的单向逆风差分格式最好.
英文摘要:
      This paper aims at investigating some problems in regional numerical weather prediction, such as the errors caused by conventional artificial boundary conditions and their related computational problems, etc. In the first place, the errors caused by the so-called "fixed boundary condi-Lion" employed for making predictions by using the advection equation, are discussed. The corresponding error equation and its solutions are given. It is shown that under this condition the errors propagate towards the central part of the tomputational domain from the boundaries with wind speed u. In f-he vicinity of the inflow boundary, the errors flatten the marching wave. But, on the contrary, in the vicinity of the outflow boundary, the wave amplifies in amplitude abruptly at the time t(= 3Λ/4 u) after the start of computation, where Λ is the wave length. At the same time, the wave becomes much narrower than that at the initial instant. In solving the shallow water equations under the condition, there are two kinds of error propagating towards the interior part of the domain at speeds of |u+c| and |u-c|,respectively, where c is the veloctiy of the external gravity wave.
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