# Re: regional average

From: <cluo_at_nyahnyahspammersnyahnyah>
Date: Tue, 14 Aug 2007 08:25:38 -0700 (PDT)

Chao

> 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
>> 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
>

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Received on Tue Aug 14 2007 - 09:25:38 MDT

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