气象上这是一个空间滤波的程序，在这个程序里面我们利用ncep的2.5*2.5*17的日平均位势高度数据

!目的是对位势高度的空间波动进行空间谐波滤波，得到空间行星尺度波和天气尺度波-This is a spatial filter process, which we use in this program ncep daily average bit 2.5* 2.5* 17 potential height data

! Aim is a high degree of spatial fluctuations of potential spatial harmonic filtering, the spatial scale planetary-scale waves and weather wave