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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">Hi all GrADS users,<br>
<br>
I want to get the correlation between dcape and rainrate using GrADS. Meanwhile, NCL is used to test the result.<br>
<br>
Assuming dcape is one time step prior to rainrate, so we can get the correlation (0.0266) using GrADS through,<br>
"set t 2 77; define dcapeave2=dcapeave(t-1); set t 1; d tcorr(dcapeave2,rainrateconvm,t=2,t=77)."<br>
<br>
Also using NCL, we can get the correlation (-0.18815) through,<br>
"ccr2=esccr(dcapeave(1:76,0,0,0),rainrateconvm(1:76,0,0,0),1)."<br>
<br>
I notice that the difference is small if there is no time lag between dcape and rainrate. Then we get the correlation "-0.1139" using GrADS and "-0.1101" using NCL.<br>
<br>
Why the difference is so big when the time lag is present between two time series?
<br>
Would you like to help me?<br>
<br>
Many thanks,<br>
<br>
Rui<br>
<br>
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