Cospectrum: How about specxy_ci?

From: Hyacinth Nnamchi <hyacinth.1_at_nyahnyahspammersnyahnyah>
Date: Fri Jun 29 2012 - 08:29:32 MDT

Hi;

The specx_ci functiom yields the confidence intervals for one time series. However, I have calculated the cospectrum line of 2 time series and would like estimate the Markov confidence intervals. But, there is no specxy_ci function (?). Does anyone know how I can estimate the Markov confidence intervals of cospectrum plot? Relevant parts of the code and the created plot are attached.

Thanks in advance,

Hyacinth

;************************************************
; set function arguments for spectrum analysis
;************************************************
  d = 0 ; detrending opt: 0=>remove mean 1=>remove mean + detrend
  sm = 5 ; smooth: should be at least 3 and odd
  pct = 0.10 ; percent taper: (0.0 <= pct <= 1.0) 0.10 common.
;************************************************
;
; Co-spectrum
 spec = specxy_anal(NEP,SWP,d,sm,pct)
  splt = specx_ci(spec,0.05,0.95)
 
;************************************************
; plotting parameters
;************************************************
   wks = gsn_open_wks("ps","specxy_ci") ; Opens a ps file
   plot = new(4,graphic) ; create graphic array

   r = True ; plot mods desired
   r@gsnDraw = False ; do not draw
   r@gsnFrame = False ; do not advance frame
   r@trYLog = True ; log scale
   r@trXLog = True
   r@trXReverse = True ; Reverse X axis values
   r@trXMinF = 2. ; manually set lower limit
   r@trXMaxF = 112. ; " upper
   r@tmXBMode = "Explicit"
   r@tmXBValues = (/"100","50","20","10","5","4","3","2","1"/)
   r@tmXBLabels = (/"100","50","20","10","5","4","3","2","1"/)
   r@tmXBMinorValues = ispan(1,20,1)
   r@xyLineThicknesses = (/4/) ; Define line thicknesses
   r@xyDashPatterns = (/1/) ; Dash patterns
   r@xyLineColors = (/"blue"/)
   r@tiMainString = "" ; title
   r@tiXAxisString = "" ; xaxis
   r@tiYAxisString = "" ; yaxis

; ************************************************
; create plot of cospectrum
;************************************************
   r@trYMinF = -.01 ; manually set lower limit
   r@trYMaxF = 5. ; " upper

   r@tiYAxisString = "Cospectrum: Confidence intervals (CI)?" ; yaxis
   plot(0)=gsn_csm_xy(wks,1/(spec@frq),spec@cospc,r); create plot
   

   r@tiYAxisString = "NEP spectrum & CI"
   r@trYMinF = .1 ; manually set lower limit
   r@trYMaxF = 10. ; " upper
   plot(1)=gsn_csm_xy(wks,1/(spec@frq),splt,r) ;plot the specx create plot
 

   r@tiYAxisString = "Spectrum of NEP" ; yaxis
   plot(2)=gsn_csm_xy(wks,1/(spec@frq),spec@spcx,r) ; create plot

   r@tiYAxisString = "Spectrum of SWP" ; yaxis
   plot(3)=gsn_csm_xy(wks,1/(spec@frq),spec@spcy,r) ; create plot
;==============================================================
; Panel the plots created
;
;==============================================================
  resP = True ; modify the panel plot
  resP@gsnPanelYWhiteSpacePercent = 0.0 ; default is 1.0
; resP@gsnPanelFigureStrings= (/"LTREND EXPT(raw)","LTREND EXPT(dtrend)"/) ; add strings to panel
  resP@amJust = "BottomLeft"
  resP@gsnMaximize = True ; large format
  resP@gsnPaperOrientation = "portrait"
  gsn_panel(wks,plot,(/2,2/),resP)
                                               

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Received on Fri Jun 29 08:29:45 2012

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