[ncl-talk] About Hodograph
Adam Phillips
asphilli at ucar.edu
Wed Nov 18 13:39:46 MST 2015
Hi Soares,
Looking at the wrf_user_intrp3d documentation:
https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_intrp3d.shtml
and assuming your height array has units of meters, it looks to me like
your input plane array should just contain a single value:
plane = 30 (when interpolating to 30m). The documentation states that you
should include more than one value if you are doing a cross-section, which
you are not.
Also, as you are interpolating to a horizontal level I think you should
specify a "h" instead of a "v".
So, try changing this:
u_plane = wrf_user_intrp3d( u,height,"v",plane,0.,False)
v_plane = wrf_user_intrp3d( v,height,"v",plane,0.,False)
to this:
u_plane = wrf_user_intrp3d( u,height,"h",30,0.,False)
v_plane = wrf_user_intrp3d( v,height,"h",30,0.,False)
Note that there is also a WRF online tutorial page describing this function
here:
http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/NCL_functions.htm#intrp3d
If you have any further issues with wrf_user_intrp3d or any other wrf
function in NCL please email wrfhelp at ucar.edu.
Adam
On Tue, Nov 17, 2015 at 8:55 PM, isakhar sakhar isakhar <
isakhar.inside13 at gmail.com> wrote:
> Dear Mr. Adam
>
> So far I am using the script (in attachment) to find wind direction and
> wind speed in 10 meter height. But when I tried to find wind speed in 30
> meter, 50 meter or 100 meter, I get the same result as 10 meter height.
>
>
>
>
> ---------------------------------------------------------------------------------------------------------------------------------------
> plane = (/ 0., 10./) ; height levels to plot - in meter
>
> ; Interpolate U,V to 0 Meters
> u_plane = wrf_user_intrp3d( u,height,"v",plane,0.,False)
> v_plane = wrf_user_intrp3d( v,height,"v",plane,0.,False)
>
> ; Calculate Wind Speed from Vectors
> spd = (u_plane*u_plane + v_plane*v_plane)^(0.5)
> windspd0(it)=spd(x,y)
>
> ; Wind direction at 10 Meters
> r2d = 45.0/atan(1.0) ; conversion factor
> (radians to degrees)
> dir = atan2(u_plane,v_plane) * r2d + 180
> dir0(it) = dir(x,y)
>
> ; Wind Speed
> spd at description = "Wind Speed"
> spd at units = "m/s"
> u_plane at units = "m/s"
>
> -------------------------------------------------------------------------------------------------------------------------------------
>
>
>
>
> I tried to change height level in function plane = (/ 0., 10./) to (/ 0.,
> 30./) or (/ 0., 50./), or (/ 0., 100./) but I still get the same wind speed.
>
> I also tried to change plane = (/ 10., 30./) for 30 meter height but I get
> error.
>
> Because now I am really interesting to know wind speed and direction in 30
> meter, 50 meter, and 100 meter height.
> Is there anything still wrong with this script ?
>
> Thank you,
> Soares
>
> On Mon, Nov 9, 2015 at 9:41 PM, Adam Phillips <asphilli at ucar.edu> wrote:
>
>> Hi Soares,
>> The error message:
>> fatal:["Execute.c":5900]:variable (time) is not in file (infile)
>> is telling you exactly what the issue is. By examining your input WRF
>> file you can see that a variable time is not present, but a variable names
>> Times is. The error message is coming from this line:
>> time = infile->time
>>
>> However, note that you do not need to exactly follow the example coding
>> Amadou pointed you to. You do not necessarily need to read in time, or
>> wind_speed and wind_direction. (Your file doesn't have those three
>> variables anyway.) All you should be doing is reading in the winds at the
>> level you are interested in (either U10/V10 or U/V), choose the grid point
>> you are interested in, and pass the wind speed and direction to the
>> create_one_station_plot function.
>>
>> wrf_ll_to_ij might be useful to find the nearest coordinate indexes to a
>> desired latitude and longitude:
>> http://www.ncl.ucar.edu/Document/Functions/Built-in/wrf_ll_to_ij.shtml
>>
>> a list of all WRF functions available in NCL is also given here:
>> http://www.ncl.ucar.edu/Document/Functions/wrf.shtml
>>
>> Hope that all helps. If after modifying your script as detailed above
>> you still have questions about how to read in and subset your WRF data I
>> highly advise you to look at the online documention including the WRF
>> online NCL tutorial and the NCL website:
>> http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Graphics/NCL/NCL_examples.htm
>> http://www.ncl.ucar.edu/Applications/wrf.shtml
>>
>> Adam
>>
>>
>>
>>
>>
>>
>> On Sun, Nov 8, 2015 at 7:03 PM, isakhar sakhar isakhar <
>> isakhar.inside13 at gmail.com> wrote:
>>
>>> Dear Mr. Adam and Mr.Amadou
>>>
>>> I just downloaded the file as you recommend and made some change
>>> according to my configuration. But after running the simulation, I get
>>> error says "fatal:["Execute.c":5900]:variable (time) is not in file (infile)
>>> ".
>>>
>>> Now I don't have any station (weather station), just a computer for
>>> running simulation only because I see there are 5 stations inside the
>>> script.
>>>
>>> Here I attach my two files, one is my hodograph modification and one is
>>> my ncdump file.
>>> Please take a look of these files.
>>>
>>> Regards,
>>> Soares
>>>
>>> On Fri, Nov 6, 2015 at 4:11 PM, Adam Phillips <asphilli at ucar.edu> wrote:
>>>
>>>> Hi Soares,
>>>> It looks to me like all you attached are functions. I do not see a
>>>> script that calls the hodograph function for instance. You need to call
>>>> hodograph from another NCL script, passing in the workstation, an array of
>>>> the wind speed, an array of the direction, and a resource list.
>>>>
>>>> For an example of how to do this, refer to a ncl-talk question from a
>>>> couple weeks back:
>>>> http://mailman.ucar.edu/pipermail/ncl-talk/2015-October/004199.html
>>>>
>>>> And see the second attachment on that page:
>>>>
>>>> http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20151022/9bdf6ef5/attachment.obj
>>>>
>>>> Coincidentally, this script holds a function that creates a hodograph
>>>> (named create_one_station_plot), and that function is called at the
>>>> bottom of the main script.
>>>>
>>>> Note that you do not have to use the ncl-talk script to do what you
>>>> want. This just provides an example where someone was creating hodographs
>>>> by calling a function external to the main script.
>>>>
>>>> Finally, no, at present there are not any hodograph examples on the NCL
>>>> website.
>>>>
>>>> Hope that helps. If not, or if you have any further questions, please
>>>> respond to the ncl-talk email list.
>>>> Adam
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Fri, Nov 6, 2015 at 12:07 AM, isakhar sakhar isakhar <
>>>> isakhar.inside13 at gmail.com> wrote:
>>>>
>>>>> Dear NCL Talk Team
>>>>>
>>>>> I want to plot Hodograph by using 2 files in attahment but I did not
>>>>> see anything, no plotting.
>>>>>
>>>>> I tried also to find hodograph in website "
>>>>> https://www.ncl.ucar.edu/Applications/ " but I could not see it.
>>>>>
>>>>> Can someone help me how to plot wind speed and direction in Hodographs?
>>>>>
>>>>> Thank you,
>>>>> Soares
>>>>>
>>>>> _______________________________________________
>>>>> ncl-talk mailing list
>>>>> ncl-talk at ucar.edu
>>>>> List instructions, subscriber options, unsubscribe:
>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Adam Phillips
>>>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>>>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
>>>>
>>>> <http://www.cgd.ucar.edu/staff/asphilli>
>>>>
>>>
>>>
>>
>>
>> --
>> Adam Phillips
>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
>>
>> <http://www.cgd.ucar.edu/staff/asphilli>
>>
>
>
--
Adam Phillips
Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
<http://www.cgd.ucar.edu/staff/asphilli>
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