[ncl-talk] Fwd: Sub : Objective analysis
Daniel Barandiaran
dbarandiaran at gmail.com
Sat Jan 23 16:32:41 MST 2016
Picking rscan values is a process that involves lots of testing, and there
is no hard and fast rule for picking them. I have used this function as
well, and have also seen the "lensing" effects you are seeing. I think this
is something that just occurs as a result of the way the extrapolation is
executed. In my experience it seems to occur most along the edges of the
grid you are converting to, or in areas with sparse observations. A clearer
understanding of what is happening under the hood will probably be found by
reading the 1959 Cressman paper on objective analysis which this function
is based on.
On Sat, Jan 23, 2016 at 4:24 PM, Adv <advita6 at gmail.com> wrote:
>
> Hi Ncl users,
>
> This is the code i use to produce attached plots . I didn't get any error.
> But there is a skewed parts here and there in the plots. I don't understand
> where is the problem. I think problem is choosing the rscan array. Could
> someone help me to pick right one? Figure shows unsmoothened values.
>
> I would appreciate any help and suggestions.
> Thank you,
> Adv
>
> ;****************************************************
> ;****************************************************
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> ;***************************************************
>
> ;***************************************************
> begin
> ;***************************************************
> strll = asciiread("stationmac.txt", -1, "string") ;
> print(strll) ; STATION","STATION_NAME", "LAT", "LON"
> print("=====")
>
> sloc = str_get_field(strll , 2, ",")
> lat = tofloat( str_get_field(strll , 3, ",") )
> lon = tofloat( str_get_field(strll , 4, ",") )
> print(sloc +" : "+lat+" "+lon)
> mnlat=(min(lat))
> mxlat=(max(lat))
> mnlon=(min(lon))
> mxlon=(max(lon))
> ;print(lon)
> print(mnlon)
> print(mxlon)
> print(mnlat)
> print(mxlat)
> mlon = 390
> dlon = -90.35 / mlon
> lonn = fspan (-116, (mlon - 1) * dlon, mlon)
> print(lonn)
> mlat = 390
> dlon = -90.35 / mlon
> lonn = fspan (-116, (mlon - 1) * dlon, mlon)
> print(lonn)
> mlat = 390
> dlat = 49.0 / mlat
> latt = fspan (40.01, (mlat - 1) * dlat, mlat)
> print(latt)
> diri="/home/dailysimms/prec-obs/"
> z1 = asciiread(diri+"t_avg_Jan-Dec1965-2005",-1,"float")
> print(z1)
> printVarSummary(z1)
> ;a = (/1,2,3,4,5,6,7,8/)
> ;Dimensions and sizes: [192372]
> ;390 rows by 50 columns
> a0 = onedtond(z1,(/390,492/))
> printVarSummary(a0)
> v = ispan (0,390,1)
> print(v)
> ;tenth of mm
> x=(regCoef(v,z1))*492
> print(x)
> set_default_fillvalue("string", "")
> opt = True
> rscan = (/5,3,1 /)
> grid = obj_anal_ic_deprecated(lon, lat, z1, lonn, latt, rscan, True)
> printVarSummary(grid)
> ;return
> ;print(grid)
> print(min(grid))
> print(max(grid))
> ;return
> grid&lat at units="degrees_north"
> grid&lon at units="degrees_east"
> printVarSummary(grid)
> ;return
> ;**************************************************
> ; plot parameters
> ;**************************************************
>
> wks = gsn_open_wks("x11","Climatemn_Temp_1965-2005") ;
> Open ps file
> gsn_define_colormap(wks,"testcmap")
> plot = new(1,graphic)
>
> res = True
> res at gsnDraw = False ; don't draw
> res at gsnFrame = False ; don't advance frame
> res at cnInfoLabelOn = False ; turn off cn info label
> res at cnLinesOn = False ; turn off contour lines
> res at cnFillOn = True ; color plot desired
> res at cnLineLabelsOn = False
> res at lbLabelBarOn = False ; turn off individual cb's
> ;res at txFontHeightF = 0.015 ; adjust font height of
> gsnLeftString/gsnRightString titles
> ;res at cnLevelSelectionMode = "ExplicitLevels" ; set
> explicit contour levels
> ;res at cnLevels = (/-2,-1,0,1,2,3,4/)
> res at vpWidthF = 0.90 ; change aspect ratio of
> plot
> res at vpHeightF = 0.90
> res at vpXF = 0.05
> res at vpYF = 0.95
>
> ; map resources for projection
> res at mpGridAndLimbOn = False
> res at gsnTickMarksOn = False
> ;***************************************************
> res at mpLimitMode = "LatLon"
> res at mpMinLatF = 40.
> res at mpMaxLatF = 49.
> res at mpMinLonF = -116
> res at mpMaxLonF = -90.1
>
> res at mpPerimOn = True ; draw box around
> map
> res at mpGeophysicalLineThicknessF = 3.0
> res at mpGeophysicalLineColor = "Black"; (/22/)
> ;res at mpNationalLineThicknessF = 3.0
> res at mpOutlineBoundarySets = "GeophysicalAndUSStates" ; add state
> boundaries
> res at mpNationalLineColor = res at mpGeophysicalLineColor
> res at mpUSStateLineThicknessF = 3.0
> res at mpUSStateLineColor = res at mpGeophysicalLineColor
>
> res at gsnAddCyclic = False
>
> res at gsnCenterStringFontHeightF = 0.02
> res at gsnCenterString = "Obs"
> plot(0) = gsn_csm_contour_map_ce(wks,grid,res)
> ;************************************************
> ; create panel
> ;************************************************
> resP = True ; modify the panel plot
> resP at gsnFrame = False ; don't advance the
> frame, so we can use gsn_text_ndc
> resP at gsnPanelLabelBar = True ; add common colorbar
> resP at lbLabelFontHeightF = 0.015 ; set font height of
> Label Bar labels
> resP at gsnPanelBottom = 0.2 ; shrink panel plot by
> setting bottom edge of plot
> resP at gsnPanelTop = 0.9 ; shrink panel plot by
> setting top edge of plot
> resP at pmLabelBarWidthF = 0.3 ; make thinner
> resP at pmLabelBarHeightF = 0.05
> resP at gsnPanelYWhiteSpacePercent = 5. ; increase spacing along
> Y-axis between panel plots
> resP at cnLinesOn = False ; turn off contour lines
> ; resP at cnFillOn = True ; color plot desired
> ; resP at lbTitleOn = True ; turn on title
> resP at lbTitleString = "degC"
> resP at lbTitleFontHeightF= .012 ; make title smaller
> resP at cnLineLabelsOn = False
> resP at txString = "Climatemn_Temp_1965-2005"
> resP at txFontHeightF = 0.019
> gsn_panel(wks,plot,(/1,1/),resP) ; now draw as one plot
>
>
> ; txres = True
> ; txres at txFontHeightF = 0.015
> ; gsn_text_ndc(wks,"Figure 16: A smaller panel plot",0.5,0.16,txres)
> frame(wks)
>
> end
>
>
>
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>
--
Danny Barandiaran
Ph.D. Candidate
Department of Plants, Soils, and Climate
Utah State University
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