Re: winds from WRF not matching RAOB

From: Hahmann, Andrea N. <ahah_at_nyahnyahspammersnyahnyah>
Date: Wed Sep 21 2011 - 00:57:36 MDT

Dear Steve

To make sure I have the right grid point I always print out the latitude and longitude of the (i,j) ncl calculates. Something like:

print(XLAT(0,locY,locX)+" "+XLONG(0,locY,locX))
In your notation and check that these values match my station coordinates.

Andrea

----
Andrea N. Hahmann
Senior Scientist
Wind Energy Division
Risų DTU
Technical University of Denmark
Risų National Laboratory for Sustainable Energy
Frederikborgvej 399, P.O. Box 49
4000 Roskilde, Denmark
Direct +45 4677 5471
Mobil: +45 2133 0550
ahah@risoe.dtu.dk
http://www.risoe.dtu.dk
From: steve kirby <thin_runner@yahoo.com<mailto:thin_runner@yahoo.com>>
Reply-To: steve kirby <thin_runner@yahoo.com<mailto:thin_runner@yahoo.com>>
Date: Tue, 20 Sep 2011 23:59:45 +0200
To: "ncl-talk@ucar.edu<mailto:ncl-talk@ucar.edu>" <ncl-talk@ucar.edu<mailto:ncl-talk@ucar.edu>>
Subject: winds from WRF not matching RAOB
Sorry  - forgot to note, in the attached figure, WRF winds are in orange; RAOB winds are in black
--Steve
----- Forwarded Message -----
From: steve kirby <thin_runner@yahoo.com<mailto:thin_runner@yahoo.com>>
To: "ncl-talk@ucar.edu<mailto:ncl-talk@ucar.edu>" <ncl-talk@ucar.edu<mailto:ncl-talk@ucar.edu>>
Sent: Tuesday, September 20, 2011 3:54 PM
Subject: winds from WRF not matching RAOB
Hi,
I'm doing some plots of RAOB's vs WRF and the WRF-extracted winds aren't matching the RAOB.  Here's the WRF portion --
=============================================================================================
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/skewt_func.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
...
a=addfile("./wrfout_d02_2010-07-16_20_00_00.nc","r");
;get the variables
 wrftc=wrf_user_getvar(a,"tc",0)
 wrftd=wrf_user_getvar(a,"td",0)
 wrfp=wrf_user_getvar(a,"pressure",0)
 wrfz=wrf_user_getvar(a,"z",0)
 uvm=wrf_user_getvar(a,"uvmet",0)
;extract u and v from uvm array and convert to knots
 u=uvm(0,:,:,:)*1.94386
 v=uvm(1,:,:,:)*1.94386
;;;;
 ; get ij point in model domain for location of interest
 ; loc(1) is touth-north (y) and loc(0) is west-east (x)
 ; ensure this point is in the domain, as we are not checking
 ; we are interested in NCL array pointers, so subtract 1
  loc=wrf_user_ll_to_ij(a,-106.93,32.28,True) ; it should read (a, lon,lat,True) is that right?
  locX=loc(0)-1
 locY=loc(1)-1
dataOpts@colTemperature<mailto:dataOpts@colTemperature> = "red"
 dataOpts@colDewPt<mailto:dataOpts@colDewPt> = "magenta"
 ;new location for winds (default is 45)
 dataOpts@xpWind<mailto:dataOpts@xpWind> = 40.
 dataOpts@colWindP<mailto:dataOpts@colWindP> = "orange"
skewT_data = skewT_PlotData (wks,skewt_bkgd,wrfp(:,locY,locX),\
                                            wrftc(:,locY,locX),\
                                            wrftd(:,locY,locX),\
                                            wrfz(:,locY,locX),\
                                            u(:,locY,locX),\
                                            v(:,locY,locX),\
                                            dataOpts)
draw(skewT_data)
=====================================================================================================
QUESTION - Do I have it right, that in the wrf_user_ll_to_ij( ) call that I use longitude, latitude (in that order) to locate the point of interest?
I have done a couple of other plots of WRF winds vs. RAOB and the winds are not matching up with those either, so I was wondering if I had something wrong in code.
Thanks,
Steve
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Received on Wed Sep 21 00:57:35 2011

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