云、辐射对中期数值预报影响的数值试验

在国家气象中心引进的EC-T42L9谱模式的基础上，用模式诊断云和模式水汽场（以下简称B方法）代替其中计算辐射时所用的纬向平均的气候云和气候水汽场（以下简称A方法），并减少垂直层以节省计算量，从而发展了一个T42L5谱模式。此外，在计算云和辐射时，还设计了方法C，调整云和辐射计算的“时空”分辩率。该文利用改进的T42L5谱模式，并以EC的1982年7月1日12时（UTC）的客观分析为初始场，进行了A、B、C三种方法的5天中期数值预报试验，较系统地研究了云和辐射在中期数值预报中的作用。数值试验的结果表明:（

Numerical Experiment of the Effects of Cloud/Radiation on the Medium-range Numerical Weather Prediction

The T42L5 spectral model has been developed on the basis of T42L9 model, with the use of model diagnosed cloud instead of climate cloud. Using EC observed analysis of 12UTC July 1, 1982 as initial field, 5-day medium-range numerical experiments have been carried out in different cloud schemes so as to dynamically investigate the effects of cloud/radiation on the medium-range NMP. The numerical results show that: (1) The model diagnosed cloud can well simulate the real distribution of the cloud in the atmosphere and modify the calculation of radiation, and consequently improve the prediction. (2) The amount of middle and high cloud in the climate cloud is much lower than the real cloud, which results in the weakening of the synoptic system, while the model diagnosed cloud can improve the prediction due to the proper consideration of the effects of cloud and radiation. (3) The model diagnosed cloud scheme is able to successfully simulate the maximum and minimum regions of the middle and high cloud which are responded to the upward and downward areas of the Hadley circulation, respectively. In the meantime, the simulated Hadley circulation of the model diagnosed cloud is much stronger than that of the climate cloud