一个全球七层大气环流谱模式及其30天长期数值天气预报试验

本模式是原北半球七层原始方程谱模式的发展，它包含了较完整的物理过程。模式的方程组求解方案能有效地克服在散度方程中以及在σ坐标系中在大地形附近计算气压梯度力项时所存在的大量之间小差的问题，模式的非线性项的谱计算方法有其优越性。本文给出了利用本模式以及用实际观测资料的客观分析场为初始场作30天长期数值天气预报试验结果。从多个个例的结果可以看出，模式的预报效果令人满意，在整个30天内，模式的预报误差都比对应的持续性误差小，而且在低纬地区也具有上述特点。这表明，本文提出的全球七层大气环流谱模式具有30天长期数值预报能力。

Experiments of the 30–Day Long–range Numerical Weather Prediction in a Seven–level Spectral Model

The present model with the considerations of more physical processes is largely is largely based on the northern hemispheric seven-level spectral model. An efficient method in the model has been given to overcome the problems involving small differences between the two large magnitudes occurring in the divergence equation, as well as in the calculation of the pressure gradient force terms in a σ-coordinate in the vicinity of mountains. The method of calculating nonlinear terms is excellent. The 30-day long-range numerical weather predictions utilizing the present model with initial conditions based on real data on lst May and 7th July 1982 have been made, and the results are satisfactory. The RMS errors of the forecasts are consistently less than those of persistence method even in lower latitudes during the entire 30–day forecasting period.