<div dir="ltr"><div><div>Mira,<br><br></div>Why did you change vcres@vcRefMagnitudeF = 10.0 to vcres@vcRefMagnitudeF = 1.0 after the first 2 plots were made? This is likely what is causing the difference.<br><br></div>-Alex<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jun 8, 2015 at 8:12 PM, <span dir="ltr"><<a href="mailto:mberdahl@envsci.rutgers.edu" target="_blank">mberdahl@envsci.rutgers.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi all,<br>
I have a 3 panel plot which shows the winds over a region. The first two<br>
panels show averages for selected years, and the third panel shows the<br>
difference between the top 2 panels. My problem is that the spacing of<br>
wind vectors is much denser in the first two plots than the third<br>
"difference" plot. Is there a reason why the grid spacing would suddenly<br>
be different (more sparse) when displaying the difference of two wind<br>
fields? The sizes (dimensions) of the u and v fields remain the same for<br>
each panel.<br>
My script and the VarSummaries for some of the variables are below.<br>
I will try to attach the pdf of the figure here if possible.<br>
Thanks very much for any help.<br>
Mira<br>
<br>
************************************************************<br>
<br>
<br>
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"<br>
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"<br>
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"<br>
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"<br>
;************************************************<br>
begin<br>
;************************************************<br>
; read in netCDF file<br>
;************************************************<br>
a = addfile("<a href="http://uwnd.mon.mean.nc" target="_blank">uwnd.mon.mean.nc</a>","r")<br>
print(a)<br>
b = addfile("<a href="http://vwnd.mon.mean.nc" target="_blank">vwnd.mon.mean.nc</a>","r")<br>
<br>
;************************************************<br>
; read in zonal [u] and meridional [v] winds (July)<br>
;************************************************<br>
<br>
u = a->uwnd(0:803,{45:90},{270:357.5})<br>
v = b->vwnd(0:803,{45:90},{270:357.5}) ; Get u, v, time (1),level<br>
(1000hpa),latitude(-90:90) and longitude(0:360) data.<br>
<br>
printVarSummary(u)<br>
printVarSummary(v)<br>
<br>
; to take the average over the first dimensions (time)<br>
;uAvgTime = dim_avg_n_Wrap(u,0)<br>
;vAvgTime = dim_avg_n_Wrap(v,0)<br>
<br>
;printVarSummary(vAvgTime)<br>
;printVarSummary(uAvgTime)<br>
<br>
; calculate speed from u and v components<br>
;speed = sqrt(uAvgTime^2+vAvgTime^2)<br>
<br>
; Calculate the seasonal averages.<br>
uDJF = month_to_season(u, "DJF")<br>
vDJF = month_to_season(v, "DJF")<br>
<br>
printVarSummary(uDJF)<br>
printVarSummary(vDJF)<br>
<br>
; from the matlab script i wrote: findExtremeYrs, i pulled out the extreme<br>
years (> or < 1std) that i want to average and plot here.<br>
<br>
; for ans = 4 (NAO)<br>
; yearList_hi = 1973 1975 1983 1989 1995<br>
2000 2007 2012<br>
; yearList_lo = 1963 1964 1965 1969 1977<br>
1979 1996 1997 2010 2011<br>
<br>
; ans = 5 (pressure)<br>
;yearList_hi = 1963 1965 1968 1969 1970<br>
1971 1977 1997 2006 2011<br>
;yearList_lo = 1973 1989 1990 1991 1995<br>
1999 2000 2007 2012<br>
<br>
;ans = 7 (longitude of IL)<br>
;yearList_hi =1966 1967 1968 1969 1974<br>
1975 1983 1994 1995 2005<br>
;yearList_lo =1963 1964 1985 1987 1991<br>
1992 1996 2002 2003 2006 2009<br>
<br>
<br>
; this data starts at 1948 (this is index 0), so 1953=5, 1963=10 etc.<br>
<br>
uDJF_NAO_lo = uDJF((/10,11,12,16,24,26,43,44,57,58/),:,:)<br>
uDJF_NAO_hi = uDJF((/20,22,30,36,42,47,54,59/),:,:)<br>
<br>
vDJF_NAO_lo = vDJF((/10,11,12,16,24,26,43,44,57,58/),:,:)<br>
vDJF_NAO_hi = vDJF((/20,22,30,36,42,47,54,59/),:,:)<br>
<br>
uAvgTime_hi = dim_avg_n_Wrap(uDJF_NAO_hi,0)<br>
uAvgTime_lo = dim_avg_n_Wrap(uDJF_NAO_lo,0)<br>
<br>
printVarSummary(uAvgTime_hi)<br>
printVarSummary(uAvgTime_lo)<br>
<br>
vAvgTime_hi = dim_avg_n_Wrap(vDJF_NAO_hi,0)<br>
vAvgTime_lo = dim_avg_n_Wrap(vDJF_NAO_lo,0)<br>
<br>
printVarSummary(vAvgTime_hi)<br>
printVarSummary(vAvgTime_lo)<br>
<br>
<br>
<br>
;************************************************<br>
; create plot<br>
;************************************************<br>
wks = gsn_open_wks("eps","Panel_NAO") ; open a ps file<br>
plot = new(3,graphic) ; create a plot array<br>
<br>
vcres = True<br>
vcres@gsnDraw = False ; dont draw<br>
vcres@gsnFrame = False ; dont advance frame<br>
vcres@cnInfoLabelOn = False ; trn off cn info label<br>
<br>
vcres = True ; plot mods desired<br>
vcres@gsnAddCyclic = False ; has to do with wrapping the longitude at 0/360<br>
vcres@vcRefAnnoOrthogonalPosF = -1.0 ; move ref vector up<br>
vcres@vcRefMagnitudeF = 10.0 ; define vector ref mag<br>
vcres@vcRefLengthF = 0.045 ; define length of vec ref<br>
vcres@vcGlyphStyle = "CurlyVector" ; turn on curly vectors<br>
vcres@vcMinDistanceF = 0.017<br>
<br>
;************************************************<br>
; Choose a subregion<br>
;************************************************<br>
vcres@mpFillOn = False ; turn off gray fill<br>
vcres@mpOutlineBoundarySets = "National" ; turn on country boundaries<br>
vcres@mpGeophysicalLineColor = "Navy" ; color of cont. outlines<br>
vcres@mpGeophysicalLineThicknessF = 1.5 ; thickness of outlines<br>
<br>
vcres@mpMaxLatF = 90 ;maximum latitude<br>
vcres@mpMinLatF = 45 ;minimum latitude<br>
vcres@mpMaxLonF = 357.5 ;maximum longitude<br>
vcres@mpMinLonF = 270 ;minimum longitude<br>
<br>
diff_u = uAvgTime_hi - uAvgTime_lo<br>
diff_v = vAvgTime_hi - vAvgTime_lo<br>
<br>
printVarSummary(diff_u)<br>
printVarSummary(diff_v)<br>
<br>
vcres@gsnLeftString = "DJF High NAO"<br>
plot(0) = gsn_csm_vector_map_ce(wks,uAvgTime_hi,vAvgTime_hi,vcres)<br>
<br>
vcres@gsnLeftString = "DJF Low NAO"<br>
plot(1) = gsn_csm_vector_map_ce(wks,uAvgTime_lo,vAvgTime_lo,vcres)<br>
<br>
<br>
vcres@vcRefMagnitudeF = 1.0 ; define vector ref mag<br>
vcres@vcRefLengthF = 0.045 ; define length of vec ref<br>
vcres@gsnLeftString = "Difference of High - Low"<br>
plot(2) = gsn_csm_vector_map_ce(wks, diff_u, diff_v,vcres)<br>
<br>
;************************************************<br>
; create panel<br>
;************************************************<br>
resP = True ; modify the panel plot<br>
resP@txString = "NAO"<br>
gsn_panel(wks,plot,(/3,1/),resP) ; now draw as one plot<br>
<br>
<br>
<br>
end<br>
<br>
<br>
<br>
OUTPUT<br>
*******************************************************<br>
Variable: vAvgTime_hi<br>
Type: float<br>
Total Size: 2736 bytes<br>
684 values<br>
Number of Dimensions: 2<br>
Dimensions and sizes: [lat | 19] x [lon | 36]<br>
Coordinates:<br>
lat: [45..90]<br>
lon: [270..357.5]<br>
Number Of Attributes: 17<br>
NMO : 0<br>
_FillValue : -9.96921e+36<br>
actual_range : ( -15.43516, 19.79167 )<br>
parent_stat : Other<br>
statistic : Mean<br>
level_desc : Surface<br>
dataset : CDC Derived NCEP Reanalysis Products<br>
var_desc : v-wind<br>
least_significant_digit : 1<br>
precision : 2<br>
missing_value : -9.96921e+36<br>
scale_factor : 1<br>
add_offset : 0<br>
units : m/s<br>
valid_range : ( -102.2, 102.2 )<br>
long_name : DJF: Monthly Mean Meridional Wind at sigma level 0.995<br>
average_op_ncl : dim_avg_n over dimension(s): time<br>
<br>
Variable: vAvgTime_lo<br>
Type: float<br>
Total Size: 2736 bytes<br>
684 values<br>
Number of Dimensions: 2<br>
Dimensions and sizes: [lat | 19] x [lon | 36]<br>
Coordinates:<br>
lat: [45..90]<br>
lon: [270..357.5]<br>
Number Of Attributes: 17<br>
NMO : 0<br>
_FillValue : -9.96921e+36<br>
actual_range : ( -15.43516, 19.79167 )<br>
parent_stat : Other<br>
statistic : Mean<br>
level_desc : Surface<br>
dataset : CDC Derived NCEP Reanalysis Products<br>
var_desc : v-wind<br>
least_significant_digit : 1<br>
precision : 2<br>
missing_value : -9.96921e+36<br>
scale_factor : 1<br>
add_offset : 0<br>
units : m/s<br>
valid_range : ( -102.2, 102.2 )<br>
long_name : DJF: Monthly Mean Meridional Wind at sigma level 0.995<br>
average_op_ncl : dim_avg_n over dimension(s): time<br>
<br>
<br>
Variable: diff_u<br>
Type: float<br>
Total Size: 2736 bytes<br>
684 values<br>
Number of Dimensions: 2<br>
Dimensions and sizes: [19] x [36]<br>
Coordinates:<br>
Number Of Attributes: 1<br>
_FillValue : -9.96921e+36<br>
<br>
Variable: diff_v<br>
Type: float<br>
Total Size: 2736 bytes<br>
684 values<br>
Number of Dimensions: 2<br>
Dimensions and sizes: [19] x [36]<br>
Coordinates:<br>
Number Of Attributes: 1<br>
_FillValue : -9.96921e+36<br>
<br>
<br>
<br>
<br>
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<br></blockquote></div><br></div>