Re: regional average

Hi Chao,

Your latitude range is 30 N to 40 N - I guess "no weighting" would be just
fine!

saji
..
* cluo_at_uci.edu <cluo_at_uci.edu> [2007-08-13 20:58:29 -0700]:

> Hi,
>
> Thanks much for help! The data I want to average are dust deposition flux
> (kg/m2/s) and satellite chla concentration (mg/3) at T62 grids, which
> method of average (no weighting or with weighting) I should use.
>
> Thanks,
> Chao
>
>
> > Another approach ...
> >
> >
> > Let, q(time,lat,lon) and use coordinate subscripting.
> >
> >
> >
> > no weighting
> >
> > qAvg = wgt_areaave_Wrap(q(:,{lat1:lat2),{lon1:lon2}),1.0,1.0, 0)
> >
> > With cosine weighting
> >
> > wgt = lat
> > wgt = cos(lat*0.01745329)
> > qAvg = wgt_areaave_Wrap(q(:,{lat1:lat2),{lon1:lon2}) \
> > ,wgty({lat1:lat2}),1.0, 0)
> > printVarSummary(qAvg)
> >
> >
> > http://www.ncl.ucar.edu/Document/Functions/Contributed/wgt_areaave_Wrap.shtml
> >
> >
> >
> >
> > Saji Njarackalazhikam Hameed wrote:
> >> Oops! step 2 should be like this:
> >>
> >> lon1=150
> >> lon2=220
> >> lat1=30
> >> lat2=40
> >>> o
> >>> data_time=dim_avg_Wrap(data({lat|lat1:lat2},{lon|lon1:lon2},time|:))
> >>
> >> saji
> >> ..
> >>
> >> * Saji Njarackalazhikam Hameed <saji_at_apcc21.net> [2007-08-14 09:32:54
> >> +0900]:
> >>
> >>> Hi Chao,
> >>>
> >>> 1. Hope data has meta-information. If not :
> >>> o describe your "data" first - maybe like this
> >>> data!0="time"
> >>> data!1="lat"
> >>> data!2="lon"
> >>> ntim=dimsizes(data(:,0,0))
> >>> data&time=ispan(1,ntim,1) ; should put more meaningful time info
> >>> data&lat=lat
> >>> data&lon=lon
> >>>
> >>> 2. Make a time series:
> >>> o data_time=dim_avg_Wrap(data(lat|:,lon|:,time|:))
> >>>
> >>> 3. Too many loops make any scripting language run slow!
> >>>
> >>> Hope it helps,
> >>>
> >>> saji
> >>>
> >>> * cluo_at_uci.edu <cluo_at_uci.edu> [2007-08-13 17:07:05 -0700]:
> >>>
> >>>> Dear NCLers,
> >>>>
> >>>> I am trying to plot time series of regional average. I have three
> >>>> dimensional data like data(ntim, nlat,nlon), and I want to do average
> >>>> from
> >>>> region 30-40N and 150E-140W. I use the script like:
> >>>>
> >>>> data_time = new ((/ntim/),typeof(data), getFillValue(data))
> >>>> n = 0
> >>>> do ilat = 0, nlat-1
> >>>> do ilon = 0, mlon-1
> >>>> if (lat(ilat).ge.30.and.lat(ilat).le.40.) then
> >>>> if (lon(ilon).ge.150.and.lon(ilon).le.220.) then
> >>>> if (.not.ismissing(data(:,ilat,ilon))) then
> >>>> data_time(:) =data(:,ilat,ilon)
> >>>> n = n + 1
> >>>> end if
> >>>> end if
> >>>> end if
> >>>> end do
> >>>> end do
> >>>> data_time(:) =data_time(:)/n
> >>>>
> >>>> This script runs too slow. I am wondering if there are some functions
> >>>> can
> >>>> be used to do regional average.
> >>>>
> >>>> Thanks for any information!
> >>>>
> >>>> Chao
> >>>>
> >>>> _______________________________________________
> >>>> ncl-talk mailing list
> >>>> ncl-talk_at_ucar.edu
> >>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
> >>> --
> >>> Saji N. Hameed
> >>>
> >>> APEC Climate Center +82 51 668 7470
> >>> National Pension Corporation Busan Building 12F
> >>> Yeonsan 2-dong, Yeonje-gu, BUSAN 611705 saji_at_apcc21.net
> >>> KOREA
> >>
> >
>
>
> _______________________________________________
> ncl-talk mailing list
> ncl-talk_at_ucar.edu
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-- 
Saji N. Hameed
APEC Climate Center          				+82 51 668 7470
National Pension Corporation Busan Building 12F         
Yeonsan 2-dong, Yeonje-gu, BUSAN 611705			saji_at_apcc21.net
KOREA
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