[ncl-talk] Wrf output at multiple mast locations

[Mary Haley]

Muhammad,

Sorry about the delay. It's been a busy week on email!

I suggest using write_table instead of asciiwrite. This allows you to write
one line of data to a file at a time, and to format it however you like.

See the attached script. This also shows how to pass an array of lat/lon
values to wrf_user_latlon_to_ij.

Note that I'm using dummy lat/lon values for "lats" and "lons". You need to
change this to be the 15 values you want.

--Mary


On Mon, Jul 17, 2017 at 6:55 PM, Muhammad Omer Mughal <
m.mughal1 at postgrad.curtin.edu.au> wrote:

> Hi Mary
>
>
> Many thanks for your reply. Kindly see the code I use now to get 2m
> temperature at one location. The problem is that I am unable to get the
> corresponding times in the ascii file. Also is there a way to use 15
> locations in line
>
> loc = wrf_user_ll_to_ij(a, 103.78538333,1.44386667, True) instead of just
> one.
>
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
> ;***********************************************
> begin
> ;***********************************************
>
> DATADir = "./"
>   FILES = systemfunc (" ls -1 " + DATADir + "wrfout_d05* ")
> a = addfiles(FILES+".nc","r")
>
> times = wrf_user_list_times(a)
> ntimes = dimsizes(times)
>
> do it = 0,ntimes-1
> ntimes = dimsizes(times)
> T2= new(ntimes,"string")
> time = it
>
> loc = wrf_user_ll_to_ij(a, 103.78538333,1.44386667, True)
> mx = loc(0) - 1 ; array pointers in NCL space
> ny = loc(1)-1
> lat1  = a[0]->XLAT(0,ny,mx)    ; the is the nearest grid point
> lon1  = a[0]->XLONG(0,ny,mx)
> tc2 = wrf_user_getvar(a,"T2",it)     ; T2 in Kelvin
> tc2 = tc2-273.16                  ; T2 in C
>  end do
> asciiwrite("2mtemperature.csv",tc2)
> end
>
>
> Muhammad Omer Mughal
> MSc BSc Mechanical Engineering
> PhD  Research Scholar
> Remote Sensing and Satellite Research Group
> Department of Imaging and Applied Physics
> Curtin University
>
> Curtin University
> Tel | +61 8 9266 7962
> Fax | +61 8 9266 2377
> Mobile | 0470 237 525
>
> Email | m.mughal1 at postgrad.curtin.edu.au <m.lynch at curtin.edu.au>
> Web | http://curtin.edu.au
>
> Curtin University is a trademark of Curtin University of Technology.
> CRICOS Provider Code 00301J (WA), 02637B (NSW)
>
>
> ------------------------------
> *From:* Mary Haley <haley at ucar.edu>
> *Sent:* Friday, 14 July 2017 10:44:04 PM
> *To:* Muhammad Omer Mughal
> *Subject:* Re: [ncl-talk] Wrf output at multiple mast locations
>
> Muhammad,
>
> For plotting WRF data, I recommend visiting this page:
>
> http://www.ncl.ucar.edu/Applications/wrf.shtml
>
> As that first box points, out, you can use wrf_user_getvar:
>
> http://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_getvar.shtml
>
> to calculate various diagnostics and/or read variables.  It has some
> examples, including how to read 2m temperature (in degK):
>
>   t2 = wrf_user_getvar(f,"T2",-1)    ; read 2m temp across all time steps
>
> In order to compare observational data with data that's on a WRF grid, you
> need to regrid or place the obs data on the WRF grid.
>
> To regrid the data using ESMF, this involves interpolation, which you may
> or may not want.
>
> See example ESMF_regrid_20.ncl at:
>
> http://www.ncl.ucar.edu/Applications/ESMF.shtml#ex20
>
> This goes from a WRF grid to another WRF grid, but the main change you
> need to make is to the "lat_src" and "lon_src" variables, which represent
> your source grid. These will need to be set the observational lat/lon 1D
> arrays in your case.
>
> If you don't want to interpolate the data, then you can try triple2grid2d,
> which we don't have any examples for, but the documentation has some code
> snippets for:
>
> http://www.ncl.ucar.edu/Document/Functions/Built-in/triple2grid2d.shtml
>
> Finally, you may also want to visit the "gridding random data" page:
>
> http://www.ncl.ucar.edu/Document/Functions/Built-in/triple2grid2d.shtml
>
> I'm not sure this is your best set of examples, but I think it's worth
> looking at all these different methods to see which one best fits your
> purpose.
>
> If you have problems with this and are able to provide us with your script
> and data, then we can help you out and maybe create a new example for our
> examples page so other users can benefit.
>
> Good luck,
>
> --Mary
>
>
>
>
>
> On Wed, Jul 12, 2017 at 6:50 PM, Muhammad Omer Mughal <
> m.mughal1 at postgrad.curtin.edu.au> wrote:
>
>> Hi
>>
>> Is it possible in NCL to grab 2m temperature time series data at multiple
>> locations in a single Wrf output file . I have about 15 stations and I want
>> to compare the temperature at those locations with Wrf simulated
>> temperature at 2m. Is there any example script that I can look at ?
>> Also I would like to compare 2m temperature at single time from Wrf and
>> observations  and plot the difference.please direct me to the relevant
>> example.
>> Thanks
>>
>>
>> ​
>> Muhammad Omer Mughal
>> MSc BSc Mechanical Engineering
>> PhD  Research Scholar
>> Remote Sensing and Satellite Research Group
>> Department of Imaging and Applied Physics
>> Curtin University
>>
>> Curtin University
>> Tel | +61 8 9266 7962 <+61%208%209266%207962>
>> Fax | +61 8 9266 2377 <+61%208%209266%202377>
>> Mobile | 0470 237 525
>>
>> Email | m.mughal1 at postgrad.curtin.edu.au
>> Web | http://curtin.edu.au
>>
>> ​ Curtin University is a trademark of Curtin University of Technology.
>> CRICOS Provider Code 00301J (WA), 02637B (NSW)
>>
>> ​
>>
>> _______________________________________________
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>
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