<div dir="ltr"><div><div><div>I am not sure why you would get a 'zero' from the quantity.<br><br>===<br><br></div>What version of NCL are you using?<br><br></div>%> ncl -V<br><br>===<br></div>Many functions in the shea_util.ncl library are preceded by<br><div><br>;------------------------------------------------------------------------------------<br>;----------------------- Unsupported: DJS -----------------------------------<br>;-----------------------------------------------------------------------------------<br><br></div><div>This means ... that I won't support them. They are developmental.<br><br>++++++++++++++++++++++++++++++++++++++++++++++++++<br><br></div><div>The 6.3.0 release (March, 2015) has two supported and documented potential vorticity functions.<br><br> <a href="http://www.ncl.ucar.edu/current_release.shtml">http://www.ncl.ucar.edu/current_release.shtml</a><br><br></div><div>[Click on 'pot_vort_isobaric']<br><br></div><div>Can you please download the latest version of NCL and use the appropriate function from that library ?<br><br></div><div>Actually, the versions in shea_util.ncl was deleted. The 6.3.0 function is located in contributed.ncl<br><br></div><div>Cheers<br><br></div><div><br><br></div><div><br></div><div>Can you <br></div><div><br><br><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Jun 13, 2015 at 3:09 AM, Nafiseh Pegahfar <span dir="ltr"><<a href="mailto:pegahfar@alumni.ut.ac.ir" target="_blank">pegahfar@alumni.ut.ac.ir</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
I write a ncl code to calculate PV(potential vorticity) at 300 mb using<br>
gfs data.<br>
after running I recievd the error of<br>
""""""""""""""""""""""""""""""""""""""""""""""""""""""""<br>
fatal:divide: Division by 0, Can't continue<br>
fatal:Div: operator failed, can't continue<br>
fatal:["Execute.c":8575]:Execute: Error occurred at or near line 3892 in<br>
file /usr/share/ncarg/nclscripts/csm/shea_util.ncl<br>
<br>
fatal:["Execute.c":8575]:Execute: Error occurred at or near line 3909 in<br>
file /usr/share/ncarg/nclscripts/csm/shea_util.ncl<br>
<br>
fatal:["Execute.c":8575]:Execute: Error occurred at or near line 133 in<br>
file PVcode_version6_3.ncl<br>
"""""""""""""""""""""""""""""""""""""""""""""""""""""""'''<br>
<br>
I checked 3892 line in shea_util.ncl it was "con = R/(s*conform(t,p,npr))"<br>
while s= -(t/theta)*dthdp. I checked "s","t","theta","dthdp" and<br>
"conform(t,p,npr)". non of them was zero.<br>
<br>
please help me what to do.<br>
some of my code is :<br>
<br>
U_00 = a->UGRD_P0_L100_GLL0(:,::-1,:) ; (time,lev,lat,lon) or<br>
(lev,lat,lon) V_00 = a->VGRD_P0_L100_GLL0(:,::-1,:) ;<br>
(time,lev,lat,lon) or<br>
(lev,lat,lon)<br>
T_00 = a->TMP_P0_L100_GLL0(:,::-1,:) ; K<br>
P_00 = (a->lv_ISBL0)<br>
P_00 = (P_00)*100<br>
P_00@units = "Pa"<br>
m=dimsizes(P_00)<br>
print ("dimsizes(P_00)="+dimsizes(P_00))<br>
<br>
L = T_00&lat_0<br>
<br>
;"""""""""""""""""""""""""""""""""""""""""""""<br>
;check "conform(T_00,P_00,0)"<br>
;""""""""""""""""""""""""""""""""""""""""""'<br>
conform_00=conform(T_00,P_00,0)<br>
test=0.0<br>
conform_00_zero_test = where(conform_00.eq.0, test+5, test)<br>
print("test="+test)<br>
<br>
;"""""""""""""""""""""""""""""""""""""""""""""<br>
;check "s= -(t/theta)*dthdp"<br>
;""""""""""""""""""""""""""""""""""""""""""'<br>
theta_test=0.0<br>
theta_00= T_00*(100000./conform(T_00,P_00,0))^0.286<br>
;print("theta_00="+theta_00)<br>
theta00_zero_test = where(theta_00.eq.0, theta_test+5, theta_test)<br>
print("theta_test="+theta_test)<br>
<br>
T_test=0<br>
T00_zero_test = where(T_00.eq.0, T_test+5, T_test)<br>
print(" T_test="+ T_test)<br>
;print("T_00="+T_00)<br>
<br>
dthdp_test=0<br>
dthdp_00 = center_finite_diff_n (theta_00,P_00,False,0,0)<br>
dthdp_00_zero_test = where(dthdp_00.eq.0, dthdp_test+5, dthdp_test)<br>
print("dthdp_test="+dthdp_test)<br>
;print("dthdp_00="+dthdp_00)<br>
;""""""""""""""""""""""""""""""""""""""""""""""""""""""""""'<br>
<br>
PV_00 = pot_vort_isobaric(P_00 ,U_00 ,V_00 ,T_00 ,L , 1, 0)<br>
printVarSummary (PV_00)<br>
PV_00_300 = PV_00 ({3000000},:,:)<br>
print ("PV_00_300"+PV_00_300)<br>
<br>
<br>
=================================<br>
Best Regards<br>
Nafiseh Pegahfar<br>
Assistant Professor<br>
Iranian National Institute for Oceanography and Atmospheric Science<br>
(<a href="http://www.inio.ac.ir" rel="noreferrer" target="_blank">http://www.inio.ac.ir</a>)<br>
Phone: (0098)21- 66944873-5 Ext. 315<br>
Fax: (0098)21- 66944869<br>
Email: (<a href="mailto:pegahfar@ut.ac.ir">pegahfar@ut.ac.ir</a>)<br>
(<a href="mailto:pegahfar@inio.ac.ir">pegahfar@inio.ac.ir</a>)<br>
=================================<br>
<br>
<br>
<br>
=================================<br>
Best Regards<br>
Nafiseh Pegahfar<br>
Assistant Professor<br>
Iranian National Institute for Oceanography and Atmospheric Science<br>
(<a href="http://www.inio.ac.ir" rel="noreferrer" target="_blank">http://www.inio.ac.ir</a>)<br>
Phone: (0098)21- 66944873-5 Ext. 315<br>
Fax: (0098)21- 66944869<br>
Email: (<a href="mailto:pegahfar@ut.ac.ir">pegahfar@ut.ac.ir</a>)<br>
(<a href="mailto:pegahfar@inio.ac.ir">pegahfar@inio.ac.ir</a>)<br>
=================================<br>
<br>
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</blockquote></div><br></div>