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大家好,我想做1990-2015年间的500hPa高度场的时间平均和距平,然后再对距平场做EOF分解,在官网上看了anom.ncl的和相关平均函数,
但是还是不太明白,一个下午都在调试这个错误,也没搞懂,来向大家请教这个问题:
dim_avg(x,0)函数是对变量x的最右边维进行平均,这里0代表什么意思,
dim_avg_n_Wrap(x,0)的解释是可以不用重置矩阵,可以对任一维度求平均,怎么使用,
我该如何设置我所想要的年份区间呢,是在输入资料的时候就设置好吗?
; eof_1.ncl
;
; Concepts illustrated:
; - Calculating EOFs
; - Using coordinate subscripting to read a specified geographical region
; - Rearranging longitude data to span -180 to 180
; - Calculating symmetric contour intervals
; - Drawing filled bars above and below a given reference line
; - Drawing subtitles at the top of a plot
; - Reordering an array
; ==============================================================
; NCL V6.4.0 has new functions eofunc_n_Wrap and
; eofunc_ts_n_Wrap that allow you to calculate the EOFs without
; first having to first reorder the data. See eof_1_640.ncl.
; ==============================================================
; Calculate EOFs of the Sea Level Pressure over the North Atlantic.
; ==============================================================
; The slp.mon.mean file can be downloaded from:
; http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surface.html
; ==============================================================
; These files are loaded by default in NCL V6.2.0 and newer
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/csm/contributed.ncl"
begin
; ==============================================================
; User defined parameters that specify region of globe and
; ==============================================================
latS = 10.
latN = 40.
lonL = 80.
lonR = 160.
yrStrt = 1990
yrLast = 2015
season = "JJA" ; choose Dec-Jan-Feb seasonal mean
neof = 3 ; number of EOFs
optEOF = True
optEOF@jopt = 0 ; This is the default; most commonly used; no need to specify.
;;optEOF@jopt = 1 ; **only** if the correlation EOF is desired
optETS = False
; ==============================================================
; Open the file: Read only the user specified period
; ==============================================================
f = addfile ("/cygdrive/d/fnl/hgt.mon.mean.nc", "r")
TIME = f->time
YYYY = cd_calendar(TIME,-1)/100 ; entire file
iYYYY = ind(YYYY.ge.yrStrt .and. YYYY.le.yrLast)
slp = f->hgt(510:824,12,:,:)
; printVarSummary(slp) ; variable overview
; ==============================================================
; dataset longitudes span 0=>357.5
; Because EOFs of the North Atlantic Oscillation are desired
; use the "lonFlip" (contributed.ncl) to reorder
; longitudes to span -180 to 177.5: facilitate coordinate subscripting
; ==============================================================
slp = lonFlip( slp )
anom = dim_rmvmean_n_Wrap(slp,0)
printVarSummary(slp) ; note the longitude coord
; ==============================================================
; compute desired global seasonal mean: month_to_season (contributed.ncl)
; ==============================================================
; SLP = month_to_season (anom, season)
nyrs = dimsizes(anom&time)
; printVarSummary(SLP)
; =================================================================
; create weights: sqrt(cos(lat)) [or sqrt(gw) ]
; =================================================================
rad = 4.*atan(1.)/180.
clat = f->lat
clat = sqrt( cos(rad*clat) ) ; gw for gaussian grid
; =================================================================
; weight all observations
; =================================================================
wSLP = anom ; copy meta data
wSLP = anom*conform(anom, clat, 1)
wSLP@long_name = "Wgt: "+wSLP@long_name
; =================================================================
; Reorder (lat,lon,time) the *weighted* input data
; Access the area of interest via coordinate subscripting
; =================================================================
xw = wSLP({lat|latS:latN},{lon|lonL:lonR},time|:)
x = wSLP(time|:,{lat|latS:latN},{lon|lonL:lonR})
eof = eofunc_Wrap(xw, neof, optEOF)
eof_ts = eofunc_ts_Wrap (xw, eof, optETS)
printVarSummary( eof ) ; examine EOF variables
printVarSummary( eof_ts )
; =================================================================
; Normalize time series: Sum spatial weights over the area of used
; =================================================================
dimxw = dimsizes( xw )
mln = dimxw(1)
sumWgt = mln*sum( clat({lat|latS:latN}) )
eof_ts = eof_ts/sumWgt
; =================================================================
; Extract the YYYYMM from the time coordinate
; associated with eof_ts [same as SLP&time]
; =================================================================
yyyymm = cd_calendar(eof_ts&time,-2)/100
;;yrfrac = yyyymm_to_yyyyfrac(yyyymm, 0.0); not used here
;============================================================
; PLOTS
;============================================================
wks = gsn_open_wks("pdf","eof") ; send graphics to PNG file
plot = new(neof,graphic) ; create graphic array
; only needed if paneling
; EOF patterns
res = True
res@gsnDraw = False ; don't draw yet
res@gsnFrame = False ; don't advance frame yet
res@gsnAddCyclic = False ; plotted dataa are not cyclic
res@mpFillOn = False ; turn off map fill
res@mpMinLatF = latS ; zoom in on map
res@mpMaxLatF = latN
res@mpMinLonF = lonL
res@mpMaxLonF = lonR
res@cnFillOn = True ; turn on color fill
res@cnLinesOn = False ; True is default
;res@cnLineLabelsOn = False ; True is default
res@cnFillPalette = "BlWhRe" ; set color map
res@lbLabelBarOn = False ; turn off individual lb's
; set symmetric plot min/max
symMinMaxPlt(eof, 16, False, res) ; contributed.ncl
; panel plot only resources
resP = True ; modify the panel plot
resP@gsnMaximize = True ; large format
resP@gsnPanelLabelBar = True ; add common colorbar
yStrt = yyyymm(0)/100
yLast = yyyymm(nyrs-1)/100
resP@txString = "HGT_500hPa: "+season+": "+yStrt+"-"+yLast
;*******************************************
; first plot
;*******************************************
do n=0,neof-1
res@gsnLeftString = "EOF "+(n+1)
res@gsnRightString = sprintf("%5.1f", eof@pcvar(n)) +"%"
plot(n)=gsn_csm_contour_map_ce(wks,eof(n,:,:),res)
end do
gsn_panel(wks,plot,(/neof,1/),resP) ; now draw as one plot
;*******************************************
; second plot
;*******************************************
; EOF time series [bar form]
rts = True
rts@gsnDraw = False ; don't draw yet
rts@gsnFrame = False ; don't advance frame yet
rts@gsnScale = True ; force text scaling
; these four rtsources allow the user to stretch the plot size, and
; decide exactly where on the page to draw it.
rts@vpHeightF = 0.40 ; Changes the aspect ratio
rts@vpWidthF = 0.85
rts@vpXF = 0.10 ; change start locations
rts@vpYF = 0.75 ; the plot
rts@tiYAxisString = "gpm" ; y-axis label
rts@gsnYRefLine = 0. ; reference line
rts@gsnXYBarChart = True ; create bar chart
rts@gsnAboveYRefLineColor = "red" ; above ref line fill red
rts@gsnBelowYRefLineColor = "blue" ; below ref line fill blue
; panel plot only resources
rtsP = True ; modify the panel plot
rtsP@gsnMaximize = True ; large format
rtsP@txString = "HGT_500hPa: "+season+": "+yStrt+"-"+yLast
year = yyyymm/100
; create individual plots
do n=0,neof-1
rts@gsnLeftString = "EOF "+(n+1)
rts@gsnRightString = sprintf("%5.1f", eof@pcvar(n)) +"%"
plot(n) = gsn_csm_xy (wks,year,eof_ts(n,:),rts)
end do
gsn_panel(wks,plot,(/neof,1/),rtsP) ; now draw as one plot
end
设置这样以后,提示在plot(n) = gsn_csm_xy (wks,year,eof_ts(n,:),rts)这一句出错:
(0) gsn_csm_xy: Fatal: The x array is not monotonically increasing.
(0) Cannot draw a bar chart.
fatal:Illegal right-hand side type for assignment
fatal:["Execute.c":8128]:Execute: Error occurred at or near line 207 in file /home/Administrator/eof_hgt500.ncl。
各路大神求解啊!
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