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一、引 言 由于云的过程根本是非线性的,它们能够直接影响大尺度环流的维持和演变。在积云参数化问题上,人们采用网格尺度预极变量的方法试图对于亚网格积云的综合影响给出定量的公式。欲达到什么程度及如何作到,这仍然是不清楚的。尤其在积云参数化方面的严重困难,似乎是由于在云体组织中存在中间尺度,一般称之为“中尺度”。这样,便出现了一个重要的问题:尺度谱的域从什么地方截止才能得到最好的效果?一个明显的可能性是去分辨个别的云,从而它们不需要参数化。这种处理方法在一些热带气旋模式中已经用过,并还在被采用,得到了有希望的成果。但是,如果我们毫无例外地采用这种方法,在云的模式中,一个有代表性的水平分辨率终究是需要的,而且它将使得大尺度模式的计算量比现在要多花费许多数量级。因此,积云参数化问题,在可预见的将来,对于大尺度模式化工作仍然是重要的。于是,提出了另一个重要问题:它对于参数化积云及其中尺度组织确实是可能的吗?
I. INTRODUCTION Since cloud processes are nonlinear at all, they can directly affect the maintenance and evolution of large-scale circulation. On the parameterization of cumulus, people use the method of grid-scale pre-polar variables to try to give a quantitative formula for the combined effect of sub-grid cumulus. To what extent and how to achieve it, it is still not clear. In particular, serious difficulties in cumulus parameterization appear to be due to the presence of intermediate scales in cloud body tissues, commonly referred to as mesoscale. In this way, an important question arises: where does the scale spectrum domain get its best results? One obvious possibility is to resolve individual clouds so that they do not require parameterization. This method of treatment has been used in some tropical cyclone modes and is still being used with promising results. However, if we adopt this approach without exception, a representative horizontal resolution is ultimately required in the cloud model, and it will make large-scale models take many orders of magnitude more computations than they are now. Therefore, the cumulus parameterization problem is still important for large-scale modeling efforts in the foreseeable future. Thus, another important question is raised: is it indeed possible for parametric cumulus and its mesoscale organizations?