That looks like standard deviation or RMSE. Either way, assume your array is VAR. Then it's<div><br></div><div>C = sqrt(amean(asum(pow(VAR - amean(VAR,x=x1,x=x2,y=y1,y=y2)),2),x=x1,x=x2,y=y1,y=y2))</div><div><br></div>
<div>OR </div><div><br><div>C = sqrt(asum(VAR - amean(VAR,x=x1,x=x2,y=y1,y=y2))/N), where N is the number of grid points over which you're summing.</div><div><br></div><div>You'll have to insert values for x1, x2, y1, and y2 yourself. You can use lat and lon instead of y and x, though.</div>
<div><br></div><div>If that fails, try breaking it into parts:</div><div>'average = amean(VAR,x=x1,x=x2,y=y1,y=y2)'</div><div>'diffsquaredsum = asum(pow(VAR-average,2),x=x1,x=x2,y=y1,y=y2)'</div><div>'SD (or) RMSE = sqrt(diffsquaredsum/N)'</div>
<div><br></div><div>Jeff Duda</div><div><br></div><div class="gmail_quote">On Sat, Feb 2, 2013 at 11:24 PM, T. haghroosta <span dir="ltr"><<a href="mailto:haghroosta@hotmail.com" target="_blank">haghroosta@hotmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Dear All,<br> <br>Could you please tell me how can I define this equation which I have attached to the email. I got confused completely, I did somethings that don't work.<br> <br><font size="3" face="Times New Roman">
Regards,</font><span class="HOEnZb"><font color="#888888"><br><font size="3" face="Times New Roman"></font> <br><font size="3" face="Times New Roman">T.</font><br><p style="margin:6pt 0cm 10pt;text-align:justify;line-height:200%" class="MsoNormal">
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Jeff Duda<br>Graduate research assistant<br>University of Oklahoma School of Meteorology<br>Center for Analysis and Prediction of Storms<br>
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