<HTML>
<HEAD>
<TITLE>CDIFF Versus HDIVG?</TITLE>
</HEAD>
<BODY>
<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>I was wondering if there is a difference in the differencing scheme between CDIFF and HDIVG. I ask because I did a modified example from the documentation, i.e., divergence vice vorticity. The documentation states that CDIFF uses centered differencing. HDIVG says the same. The images suggest something else unless I’m missing something.<BR>
<BR>
CDIFF file<BR>
if(var='DIV')<BR>
'run bluewhitered.gs -2.0 .5 10'<BR>
'define dv = cdiff(vgrdprs,x)'<BR>
'define dx = cdiff(lon,x)*3.1416/180'<BR>
'define du = cdiff(ugrdprs*cos(lat*3.1416/180),y)'<BR>
'define dy = cdiff(lat,y)*3.1416/180'<BR>
'display (du/dx+dv/dy)*1e5/(6.37e6*cos(lat*3.1416/180))'<BR>
'run cbarn.gs 0.8 1 10.4 4.7'<BR>
endif<BR>
<BR>
HDIVG file<BR>
if(var='DIV')<BR>
'run bluewhitered.gs -2.0 .5 10'<BR>
'd 1e5*hdivg(ugrdprs,vgrdprs)'<BR>
'run cbarn.gs 0.8 1 10.4 4.7'<BR>
Endif<BR>
<BR>
Here are the images in order...<BR>
<BR>
Thank you for any comments,<BR>
<BR>
Robert LeeJoice<BR>
PhD Candidate, Naval Postgraduate School<BR>
</SPAN></FONT>
</BODY>
</HTML>