高度场垂直插值方法的数值预报试验

TEST OF VERTICAL INTERPOLATION METHODS FOR GEOPOTENTIAL FIELD BY NUMERICAL PREDICTION EXPERIMENTS

本文假设温度场与气压对数成逐段线性分布。在有地形时,气压梯度力项采用在P坐标系计算的方法,即回插法。分别用理想地形和温压场分布及两个实例检验了高度场垂直插值不同方法的误差。结果表明,假设高度场随气压对数平方成逐段线性分布的方法,可以简化计算,节省机时,计算精度也较高。

The relation bet-ween the iemperature and the logarithm pressure is asstmed to be locally linear. The pressure gradient force in a model with topography is calculated at the constant pressure surface, i. e. by using the so-called interpolation method. The errors of the interpolation methods with different schemes are ana-lized and checked with an ideal topography and temperatuie and geopotential height fields, as well as with two real cases. Results show that the interpolation scheme of assuming the linear relation between the geopotential and the lnp locally is as accurate as the usual scheme with assumption of linear relation between T and lnp, it can also save computer time.