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

[Mary Haley]

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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