The numerical methods utilized in solving the set of mathematical equations involve calculating the spatial rate of change of variables , which means a priori grid point value information along the boundary outside the model domain has to be separately provided to set up time - dependent boundary conditions for computing the governing equations :計算有關數(shù)學方程組的數(shù)值方法,牽涉到變數(shù)在空間的分布變化,故此亦需要另外提供模式范圍以外的網(wǎng)格點值,從而按時間設定邊界條件,以完成基本方程組的運算。