Re: regional average

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
>

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Received on Mon Aug 13 2007 - 19:37:30 MDT