[ncl-talk] Vertical Cross-Section

[BasitAli Khan]

Thanks Jamson for the quick response. I am afraid the issue is not terrain
or terrain smoothing. Its about the lowest two levels that are not being
realized by NCL. I, however, already tried all available cross-section
scripts and all of them have the same problem. Actually if you look at
your plot, it also has the same problem. It is not apparent because you
are plotting the entire vertical depth that is 20 km. If you plot only the
lowest one kilometer of your domain, you could easily see that the lowest
level data is missing.

Regards,

b:)
----
Basit A. Khan, Ph.D.

Postdoctoral Research Fellow

Division of Physical Sciences & Engineering

Office# 3204, Level 3, Building 1,

King Abdullah University of Science & Technology

4700 King Abdullah Blvd, Box 2753, Thuwal 23955 ­6900,

Kingdom of Saudi Arabia.



Office: +966(0)12 808 0276,  Mobile: +966(0)5 0860 3617

E-mail: basitali.khan at kaust.edu.sa


Skype name: basit.a.khan






On 10/2/14 11:07 PM, "jmason at eos.ubc.ca" <jmason at eos.ubc.ca> wrote:

>I use this script
>
>http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/Examples/CROSS_SE
>CTION/wrf_CrossSection_add_smooth_terrain.ncl
>
>from the cross section examples
>
>http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/NCL_examples.htm
>
>you can change the pivot point to your j,i index
>
>plane = (/ 57, 62 /); (j,i) index pivot point is center of domain
>
>this should be the plot command to avoid the skewed smooth terrain
>
>  plot = wrf_overlays(a,wks,(/contour_rh,contour_tc/),pltres)
>
>I have attached my WRF x section of wind speed and isentropes, all levels
>plotted fine for me.
>
>good luck
>
>
>
>
>> Hello,
>>
>> A couple of years ago I found that in the Vertical cross-sections, NCL
>> does not seems  to plot the few lowest levels (at least WRF data), so I
>> always used well trusted  GrADS for vertical cross-sections. However,
>>this
>> time i have no option but to use NCL and facing the same problem again.
>> Please see the attached plot and the ncl script.
>>
>> In the attached vertical cross section i have plotted the first 1 km.
>> Height on y-axis and longitude on x-axis. The  horizontal extent from
>> 37.5E to 39.3E  is the sea surface. The white space over the sea surface
>> is actually the data that NCL did not read and put it as missing values
>>in
>> the first two levels. NCL has started plotting data from the 3rd level
>>at
>> 206m Above Sea Surface. The wrfout data form a single point on the sea
>> surface (Longitude 38.0E) is as follows:
>>
>> Pressure(hPa)
>> (0) 999.4364
>> (1) 991.2365
>> (2) 980.1375
>> (3) 966.2803
>> (4) 949.0901
>> (5) 927.6281
>>
>> Height (m)
>> (0) 30.53536
>> (1) 104.9377
>> (2) 206.3695
>> (3) 335.6851
>> (4) 498.7719
>> (5) 706.6218
>>
>> Theta
>> (0) 302.5804
>> (1) 308.4214
>> (2) 312.7661
>> (3) 316.1294
>> (4) 317.4146
>> (5) 317.9083
>>
>>
>>
>> By looking at the plot it is clear that NCL missed the first two levels
>> and has started plotting data from 206 m onwards. Pressure field is
>> plotted from 980 onwards instead of 999 hPa. Theta contour at the lowest
>> level is 312K while in the wrfout data it is 302.5 K.
>>
>> Still when i plot the same cross-section with GrADS, i get all the
>> vertical levels and data and the sea-surface (37.5E to 39.3E) is also
>> plotted close to zero
>>
>> I wonder if any of our NCL /WRF experts (i am cc'ing it to wrfhelp also)
>> can help in fixing this problem.
>> Thank you in advance for your much appreciated help.
>>
>> b:)
>> ----
>> Basit A. Khan, Ph.D.
>> Postdoctoral Research Fellow
>> Division of Physical Sciences & Engineering
>> Office# 3203-CU-12, Level 3, Building 1,
>> King Abdullah University of Science & Technology
>> 4700 King Abdullah Blvd, Box 2753, Thuwal 23955 ­6900,
>> Kingdom of Saudi Arabia.
>>
>> Office: +966(0)12 808 0276,  Mobile: +966(0)5 0860 3617
>> E-mail: basitali.khan at kaust.edu.sa<mailto:basitali.khan at kaust.edu.sa>
>> Skype name: basit.a.khan
>>
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