关于grads脚本程序的问题

nannanzhu998

'reinit'
"open D:\data\grib20131124\grib2013112318.ctl"
'set lat 15 55'
'set lon 65 150'
'set lev 900 100'
'set grads off'
'set mpdset cnworld'
"set grid off"
"define prs=lev"
******theta--位温，ste--相当位温
'define theta=tmpprs*pow((1000/lev),0.2854)'
"define dtheta=tmpprs(z-1)*pow(1000/lev(z-1),0.286)-tmpprs(z+1)*pow(1000/lev(z+1),0.286)"
***"define dtheta=theta(z-1)-theta(z+1)"
**********
'define dx=cdiff(lon,x)*(111177*cdiff(lon,x)*cos(lat*3.1415/180))'
'define dy=(111177*cdiff(lat,y))'
'define thetadx=cdiff(theta,x)/dx'
'define thetady=cdiff(theta,y)/dy'
'define dp=100*(lev(z-1)-lev(z+1))'
'define div=hdivg(ugrdprs,vgrdprs)'
'define domgadx=cdiff(VVELprs,x)/dx'
'define domgady=cdiff(VVELprs,y)/dy'
'define f32=cdiff(ugrdprs,x)/dx-cdiff(vgrdprs,y)/dy'
'define f33=thetadx*thetady(cdiff(vgrdprs,x)/dx+cdiff(ugrdprs,y)/dy'
'define f2=-0.5*abs(thetadx+thetady)*div'
'define f3=-0.5/abs(thetadx+thetady)*((thetadx)*(thetadx)-(thetady)*(thetady))*f32+f33'
'define f4=-0.5/abs(thetadx+thetady)*(dtheta/dp)*(thetadx*domgadx+thetady*domgady)'
'define F=f2+f3+f4'
"set lev 850"
"set lat 30 50"
"set lon 90 140"
'd F'