[ncl-talk] Wrong with overlaying wind vectors on contour plots (X-axis is Longtitude and Y-axis is Pressue(Height))

[Zhu CE]

Yes, I meant  to plot UGRD and WGRD in gsn_csm_vector call.


The reason why I multiplied the return value of omega_to_w by 10 is the W is so small and I wanted to make W equaled to U so the wind vectors looked normally.


However, when I try to set res at vcMapDirection = False, everthing seems OK.  


Are there any mistakes I had done in those attemps? Please tell me, thanks a lot.






At 2017-07-10 21:05:51, "Mary Haley" <haley at ucar.edu> wrote:

Did you mean to plot UGRD and WGRD in your gsn_csm_vector call? If so, the issue may be either with your data or "omega_to_w".


Why are you multiplying the return value of omega_to_w by 10?


    WGRD = omega_to_w(VVEL_P0,pres,TMP_P0(10:30,:,:))*10


Please read the documentation for omega_to_w closely to make sure you are inputting the correct parameters with the correct expected units:


http://www.ncl.ucar.edu/Document/Functions/Contributed/omega_to_w.shtml



If you look the code for "omega_to_w", which is in $NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl, the calculation is simply:


   RGAS = 287.058            ; J/(kg-K) => m2/(s2 K)                    GRAV = 9.80665            ; m/s2                                    rho  = p/(RGAS*t)         ; density => kg/m3                        w    = -omega/(rho*GRAV)  ; array operation  


If you continue to have problems, please back to ncl-talk.


Thank you,


--Mary




On Fri, Jul 7, 2017 at 11:16 PM, Zhu CE <lovingzhuce at 163.com> wrote:

Hi everyone,


I am trying to draw plots which overlay wind vectors on contour plots.


Here, the X-axis is Longtitude and Y-axis is Pressue(Height).


When I used wplot1 = gsn_csm_vector(wks,UGRD(:,232,:),WGRD(:,232,:),resV) and overlay(plot1,wplot1) to draw plot, a wrong figure I have gotten, only U-wind was drawn and no W-wind was drawn.


What did I do wrong? Could you help me? Thanks a lot.


P.S. Attachments are NCL script and the wrong figure.


Zhu




 


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