Dennis,
Those examples are very complicate. I am not interested in studying
regridding; but want to use the reliable function to get the fields with a
lower resolution. Will those scripts be simplified to regridding functions
in the future?
Thanks,
Yi-Chih
On Tue, Dec 10, 2013 at 9:16 AM, Dennis Shea <shea@ucar.edu> wrote:
> You can always look at the contents of contributed.ncl
> where area_hi2lores_Wrap is located. In fact, *all* _Wrap functions are
> in contributed.ncl
>
>
> %> less $NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl
>
> Search for: area_hi2lores_Wrap
>
> ===
> The comment "but the patterns of precipitation changed
>
> dramatically; while the wind fields remained the same"
>
> "Winds" tend to be correlated in space. Averaging over
> small regions is not likely to change the patterns much.
>
> "Precipitation" may be spatially correlated if you are
> talking about monthly means, in particular, climatologies.
> Generally, the patterns not change much.
>
> However, if you are using 3/6/12-hr snapshots or daily means,
> the patterns could change 'a lot' because
> precipitations is generally highly 'fractal'.
>
> ===
> FYI: area_hi2lores (_Wrap) is a very old function.
> It is recommended that the new ESMF regrid functions be
> used for regridding. These are high quality and offer
> a true conservative remap capability. Conservative
> remapping is recommended for precipitation.
>
> http://www.ncl.ucar.edu/Applications/ESMF.shtml
>
>
>
>
> On 12/9/13, 4:49 PM, Adam Phillips wrote:
>
>> Hi Yi-Chih,
>> I don't think it has anything to do with you regridding precipitation as
>> opposed to wind vectors. I think it has to do with your LAT/LON arrays.
>> I would think that the units attribute requirement would be necessary no
>> matter what the input LAT/LON arrays are, so I'm honestly not sure..
>> Adam
>>
>> On 12/09/2013 04:45 PM, Yi-Chih Huang wrote:
>>
>>> Adam,
>>>
>>> Thanks much for the suggestion. It was working. But a basic
>>> question is why to give units to LON and LAT is necessary for
>>> precipitation; while there is no need to do so in wind vectors? What
>>> made the difference?
>>>
>>> Thanks a lot,
>>>
>>> Yi-Chih
>>>
>>>
>>> On Tue, Dec 10, 2013 at 2:19 AM, Adam Phillips <asphilli@ucar.edu
>>> <mailto:asphilli@ucar.edu>> wrote:
>>>
>>> Hi Yi-Chih,
>>> Those error messages are hinting that the issue is either in your
>>> input latitude/longitude arrays into area_hi2lores_Wrap or when
>>> you go to plot the regridded arrays. (I am honestly unclear
>>> whether area_hi2lores_Wrap requires the units attribute to be set
>>> for input/output latitude/longitude arrays.)
>>>
>>> I would first try adding units attributes to the LAT/LON arrays,
>>> and add some print statements to make sure the input
>>> pcp&lat/pcp&lon arrays contain the necessary units attributes:
>>>
>>> LON = fspan( 31.25,158.75, 52)
>>> LAT = fspan(-28.75, 28.75, 24)
>>> LON@units = "degrees_east"
>>> LAT@units = "degrees_north"
>>> printVarSummary(pcp&lon) ; is a units attribute present?
>>> printVarSummary(pcp&lat)
>>>
>>> opt = True
>>> opt@critpc = 50 ; require only 50% of the values to
>>> be precent
>>> pLo = area_hi2lores_Wrap (pcp&lon,pcp&lat, pcp , True, 1, LON,
>>> LAT, False)
>>> printVarSummary(pLo&LON) ; is a units attribute present?
>>> printVarSummary(pLo&LAT)
>>>
>>> If you need to assign a units attribute to pcp&lat for instance:
>>> pcp&lat@units = "degrees_north"
>>>
>>> Hope that helps. If not, please respond to ncl-talk.
>>> Adam
>>>
>>>
>>> On 12/09/2013 12:37 AM, Yi-Chih Huang wrote:
>>>
>>>> Hello,
>>>>
>>>> I am trying to use area_hi2lores_Wrap to obtain the
>>>> precipitation and wind fields in different low resolutions. I
>>>> used the same commands; but the patterns of precipitation changed
>>>> dramatically; while the wind fields remained the same. When "pLo
>>>> = area_hi2lores_Wrap (pcp&lon,pcp&lat, pcp , True, 1, LON, LAT,
>>>> False)" was commented, there was no such a warning message as
>>>> "Data either does not contain a valid latitude coordinate array
>>>> or doesn't contain one at all." I attached the commands, output
>>>> of printVarSummary, warning message, and the script as follows.
>>>> Could anyone tell me what was wrong with precipitation field in
>>>> area_hi2lores_Wrap?
>>>>
>>>> Thanks much,
>>>>
>>>> Yi-Chih
>>>>
>>>> #####
>>>> LON = fspan( 31.25,158.75, 52)
>>>> LAT = fspan(-28.75, 28.75, 24)
>>>> opt = True
>>>> opt@critpc = 50 ; require only 50% of the values
>>>> to be precent
>>>> pLo = area_hi2lores_Wrap (pcp&lon,pcp&lat, pcp , True, 1, LON,
>>>> LAT, False)
>>>>
>>>> LON := fspan( 30.,160., 261)
>>>> LAT := fspan(-30., 30., 121)
>>>> opt = True
>>>> opt@critpc = 50 ; require only 50% of the values
>>>> to be precent
>>>> uLo = area_hi2lores_Wrap (uwnd&lon, uwnd&lat, uwnd, True, 1,
>>>> LON, LAT, False)
>>>> vLo = area_hi2lores_Wrap (vwnd&lon, vwnd&lat, vwnd, True, 1,
>>>> LON, LAT, False)
>>>> #####
>>>> Variable: uLo
>>>> Type: float
>>>> Total Size: 126324 bytes
>>>> 31581 values
>>>> Number of Dimensions: 2
>>>> Dimensions and sizes: [LAT | 121] x [LON | 261]
>>>> Coordinates:
>>>> LAT: [-30..30]
>>>> LON: [30..160]
>>>> Number Of Attributes: 13
>>>> DataFreq : Monthly
>>>> average_op_ncl : dim_avg_n over dimension(s): year
>>>> lv_ISBL1 : 850
>>>> center : US National Weather Service - NCEP (WMC)
>>>> long_name : u-component of wind
>>>> units : m/s
>>>> level_indicator : 100
>>>> gds_grid_type : 0
>>>> parameter_table_version : 2
>>>> parameter_number : 33
>>>> model : Climate Data Assimilation System (CDAS)
>>>> initial_time : 02/05/2006 (00:00)
>>>> _FillValue : 1e+20
>>>>
>>>> Variable: pLo
>>>> Type: float
>>>> Total Size: 4992 bytes
>>>> 1248 values
>>>> Number of Dimensions: 2
>>>> Dimensions and sizes: [lat | 24] x [lon | 52]
>>>> Coordinates:
>>>> lat: [-28.75..28.75]
>>>> lon: [31.25..158.75]
>>>> Number Of Attributes: 12
>>>> _FillValue : 1e+20
>>>> initial_time : 02/05/1981 (00:00)
>>>> model : Climate Data Assimilation System (CDAS)
>>>> parameter_number : 59
>>>> parameter_table_version : 2
>>>> gds_grid_type : 0
>>>> level_indicator : 1
>>>> units : kg/m^2/s
>>>> long_name : Precipitation rate
>>>> center : US National Weather Service - NCEP (WMC)
>>>> average_op_ncl : dim_avg_n over dimension(s): time
>>>> DataFreq : Monthly
>>>> (0) 0
>>>> (0) check_for_y_lat_coord: Warning: Data either does not
>>>> contain a valid latitude coordinate array or doesn't contain one
>>>> at all.
>>>> (0) A valid latitude coordinate array should have a 'units'
>>>> attribute equal to one of the following values:
>>>> (0) 'degrees_north' 'degrees-north' 'degree_north'
>>>> 'degrees north' 'degrees_N' 'Degrees_north' 'degree_N' 'degreeN'
>>>> 'degreesN' 'deg north'
>>>> (0) check_for_lon_coord: Warning: Data either does not
>>>> contain a valid longitude coordinate array or doesn't contain one
>>>> at all.
>>>> (0) A valid longitude coordinate array should have a 'units'
>>>> attribute equal to one of the following values:
>>>> (0) 'degrees_east' 'degrees-east' 'degree_east' 'degrees
>>>> east' 'degrees_E' 'Degrees_east' 'degree_E' 'degreeE' 'degreesE'
>>>> 'deg east'
>>>> (0) 1
>>>> yhuang@arc-env:/fs3/yhuang/nmm$
>>>>
>>>> #####
>>>> load "$SysE/lib/ncl/helper_libs.ncl"
>>>>
>>>> begin
>>>> latS = -30.0
>>>> latN = 30.0
>>>> lonE = 30.0
>>>> lonW = 160.0
>>>>
>>>> dir1 = "/fs3/SysE_DB/nmm/NMM/Monthly/Mean/"
>>>> yrStrt = 1981
>>>> yrLast = 2006
>>>> year = ispan(yrStrt, yrLast,1) ; integer
>>>> yrDir = year + "/" ; string
>>>> varName= (/"precip"/)
>>>> nyr = dimsizes(year)
>>>>
>>>> dir = str_concat(dir1+yrDir(0))
>>>> fil = systemfunc("cd "+dir+" ; ls precip.nc
>>>> <http://precip.nc>") ;;;;;;;; read precipitation
>>>>
>>>> f = addfile (dir+fil, "r")
>>>> x = f->$varName(0)$
>>>> dims= getfilevardims(f,varName(0))
>>>> xs = x(:,{latS:latN},{lonE:lonW}) ; JJAS tropical Pacific
>>>> xu = dim_avg_n_Wrap( xs,0)
>>>> ds = dimsizes(xs)
>>>> xx = new((/nyr,ds(0),ds(1),ds(2)/),float)
>>>> YYYYMM= new ( (/nyr,ds(0)/), double)
>>>> printVarSummary(xs)
>>>> printVarSummary(YYYYMM)
>>>>
>>>> delete (fil)
>>>> do ny= 0,nyr-1
>>>> dir = str_concat(dir1+yrDir(ny))
>>>> fil = systemfunc("cd "+dir+" ; ls precip.nc <http://precip.nc
>>>> >")
>>>>
>>>> f = addfile (dir+fil, "r")
>>>>
>>>> x := f->$varName(0)$
>>>> dims= getfilevardims(f,varName(0))
>>>> xs := x(:,{latS:latN},{lonE:lonW}) ; Indian Ocean
>>>> xx(ny,:,:,:)= xs
>>>> YYYYMM(ny,:) = cd_calendar(xs&$xs!0$, 1)
>>>> end do
>>>> printMinMax(xx,True)
>>>> print(YYYYMM(0:2,0:3))
>>>>
>>>> xx!0 = "year"
>>>> xx!1 = "month"
>>>> pcp = dim_avg_n_Wrap( xx,(/0,1/) ) *86400 ; kg/m^2/s -> mm/day
>>>> copy_VarMeta(xu,pcp)
>>>> printMinMax(pcp,True)
>>>> printVarSummary(pcp)
>>>>
>>>> LON = fspan( 31.25,158.75, 52)
>>>> LAT = fspan(-28.75, 28.75, 24)
>>>> opt = True
>>>> opt@critpc = 50 ; require only 50% of the values
>>>> to be precent
>>>> pLo = area_hi2lores_Wrap (pcp&lon,pcp&lat, pcp , True, 1, LON,
>>>> LAT, False)
>>>> pLo!0 = "lat"
>>>> pLo!1 = "lon"
>>>> printVarSummary(pcp&lon)
>>>> printVarSummary(pcp&lat)
>>>> printVarSummary(LON)
>>>> printVarSummary(LAT)
>>>>
>>>> delete ([/fil,varName/])
>>>> dir1= "/fs3/SysE_DB/nmm/NMM/Monthly/Mean/"
>>>> dir = str_concat(dir1+yrDir(0))
>>>> fil = systemfunc("cd "+dir+" ; ls *wnd_850.nc
>>>> <http://wnd_850.nc>") ; input file name(s)
>>>>
>>>> f = addfile (dir+fil(0), "r")
>>>>
>>>> varName= (/"uwnd","vwnd"/)
>>>> x := f->$varName(0)$
>>>> dims = getfilevardims(f,varName(0))
>>>> xs := x(:,{latS:latN},{lonE:lonW}) ; Indian Ocean
>>>> ds = dimsizes(xs)
>>>> xx := new((/nyr,ds(1),ds(2)/),float,"No_FillValue")
>>>>
>>>> delete (fil)
>>>> do nf= 0,1
>>>> do ny= 0,nyr-1
>>>> dir = str_concat(dir1+yrDir(ny))
>>>> fil = systemfunc("cd "+dir+" ; ls *wnd_850.nc
>>>> <http://wnd_850.nc>") ; input file name(s)
>>>>
>>>>
>>>> f = addfile (dir+fil(nf), "r")
>>>> x = f->$varName(nf)$
>>>> dims = getfilevardims(f,varName(nf))
>>>> xs := x(:,{latS:latN},{lonE:lonW}) ; Indian Ocean
>>>> xy = dim_avg_n_Wrap( xs, 0 )
>>>> xx(ny,:,:)= xy
>>>> xx!0 = "year"
>>>>
>>>> if ( ny .eq. nyr-1 .and. nf .eq. 0 ) then
>>>> uwnd= dim_avg_n_Wrap( xx, 0 )
>>>> else if ( ny .eq. nyr-1 .and. nf .eq. 1 ) then
>>>> vwnd= dim_avg_n_Wrap( xx, 0 )
>>>> end if
>>>> end if
>>>> end do
>>>> end do
>>>> printVarSummary(uwnd)
>>>>
>>>> LON := fspan( 30.,160., 261)
>>>> LAT := fspan(-30., 30., 121)
>>>> opt = True
>>>> opt@critpc = 50 ; require only 50% of the values
>>>> to be precent
>>>> uLo = area_hi2lores_Wrap (uwnd&lon, uwnd&lat, uwnd, True, 1,
>>>> LON, LAT, False)
>>>> vLo = area_hi2lores_Wrap (vwnd&lon, vwnd&lat, vwnd, True, 1,
>>>> LON, LAT, False)
>>>> printVarSummary(uwnd&lon)
>>>> printVarSummary(uLo)
>>>> printVarSummary(pLo)
>>>>
>>>> wks= gsn_open_wks("X11","pcpWind_nmm")
>>>> gsn_define_colormap(wks,"BlueRed")
>>>>
>>>> pres= True
>>>> opt= True
>>>> myfill(pres,opt)
>>>> pres@gsnAddCyclic = False
>>>> pres@mpMinLatF = -30
>>>> pres@mpMaxLatF = 30
>>>> pres@mpMinLonF = 30
>>>> pres@mpMaxLonF = 160
>>>>
>>>> pres@cnFillOn = True
>>>> pres@gsnSpreadColors = True ; use full colormap
>>>> pres@gsnSpreadColorStart = 10 ; for BlueRed
>>>> pres@gsnSpreadColorEnd = 250 ; for BlueRed
>>>> pres@cnLevelSelectionMode = "ManualLevels"
>>>> pres@cnMinLevelValF = 1.
>>>> pres@cnMaxLevelValF = 20.
>>>> pres@cnLevelSpacingF = 1.
>>>>
>>>> pres@lbLabelBarOn = True
>>>> pres@pmLabelBarWidthF= 0.8
>>>> pres@lbLabelStride = 4
>>>> pres@mpFillOn = False
>>>> pres@mpOutlineBoundarySets = "National" ; turns on
>>>> country boundaries.
>>>> pres@gsnRightString = "mm/day"
>>>> pres@gsnLeftString = "NMM: Average Monthly Precipitation Rate
>>>> during JJAS"
>>>> pres@cnFillDrawOrder = "Predraw"
>>>> pres@gsnDraw = False
>>>> pres@gsnFrame = False
>>>> print("0")
>>>> plot1= gsn_csm_contour_map(wks,pLo,pres)
>>>> print("1")
>>>>
>>>> wres= True
>>>> wres@vcRefMagnitudeF = 10.0 ; define vector
>>>> ref mag
>>>> wres@vcRefLengthF = 0.045 ; define length
>>>> of vec ref
>>>> wres@vcMinDistanceF = 0.025 ; thin out
>>>> windbarbs
>>>> wres@vcVectorDrawOrder = "Predraw"
>>>> wres@gsnLeftString = "NMM: Average Monthly Wind
>>>> Vectors on 850 hPa during JJAS"
>>>> wres@gsnLeftStringFontHeightF = 0.025
>>>> wres@gsnRightStringFontHeightF = 0.025
>>>> wres@gsnDraw = False
>>>> wres@gsnFrame = False
>>>> plot2= gsn_csm_vector(wks,uLo,vLo,wres)
>>>>
>>>> overlay(plot1,plot2)
>>>> maximize_output(wks,True)
>>>> end
>>>>
>>>>
>>>> _______________________________________________
>>>> ncl-talk mailing list
>>>> List instructions, subscriber options, unsubscribe:
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>>>>
>>>
>>> -- ____________________________________________________________
>>> __
>>> Adam Phillipsasphilli@ucar.edu <mailto:asphilli@ucar.edu>
>>>
>>> NCAR/Climate and Global Dynamics Division(303) 497-1726
>>> <tel:%28303%29%20497-1726> P.O. Box 3000
>>> Boulder, CO 80307-3000http://www.cgd.ucar.edu/cas/asphilli
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> ncl-talk mailing list
>>> List instructions, subscriber options, unsubscribe:
>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>
>>
>>
>>
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Received on Mon Dec 9 17:52:42 2013
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