[gradsusr] hdivg function

[Yaqiang Wang]

The GrADS documentation said that the cdiff function may be used to
duplicate the calculation done by the hcurl function:

define dv = cdiff(v,x)
define dx = cdiff(lon,x)*3.1416/180
define du = cdiff(u*cos(lat*3.1416/180),y)
define dy = cdiff(lat,y)*3.1416/180
display (dv/dx-du/dy)/(6.37e6*cos(lat*3.1416/180))

But there is no description of hdivg function. I guess hdivg function
could be duplicated using cdiff function as following. Please anybody
tell me if it is correct or not. Thanks!

define dv = cdiff(v,x)
define dx = cdiff(lon,x)*3.1416/180
define du = cdiff(u*cos(lat*3.1416/180),y)
define dy = cdiff(lat,y)*3.1416/180
display (du/dx+dv/dy)/(6.37e6*cos(lat*3.1416/180))

Yaqiang Wang

Chinese Academy of Meteorological Sciences
yaqiang.wang at gmail.com