# [ncl-talk] question about "dtrend" function

Verena Lili verena.prick at gmail.com
Fri Sep 5 15:12:16 MDT 2014

```Hi Denis,

I meant something like this (attached).
My data is zonal mean Methanes (lat,time).
How could i determine the standard deviation of the trend each latitudes.
Thanks

On Friday, September 5, 2014, Dennis Shea <shea at ucar.edu> wrote:

> This question is a bit ambiguous.
>
> Assuming y(time,lat,lon)      ; (ntim,nlat,mlon)
>
>    yNew = dtrend_n(y, True, 0)                     ;
> yNew=dtrend(y(lat|:,lon|:,time|:), True)
>
>    slope  = *onedtond*
> <http://www.ncl.ucar.edu/Document/Functions/Built-in/onedtond.shtml>
> (yNew at slope,(/nlat,nlon/))    ; slope(nlat,mlon)
>    copy_VarCoords(y(0,:,:), slope)
>    slope at long_name = "..."
>    slope at units           = "..."
>    printVarSummary(slope)
>
> ; arithmetic stddev
>
>    slope_std = stddev(slope)
>
> The weighted stddev could also be determined by weight the grid by (say)
>
>
>
>
>
>
>
> On Sat, Aug 30, 2014 at 2:51 PM, Verena Lili <verena.prick at gmail.com
> <javascript:_e(%7B%7D,'cvml','verena.prick at gmail.com');>> wrote:
>
>> Hallo,
>>
>> Anybody try to have a standard deviation of the trend using "dtrend"
>> function? I'd like to plot the trend values together with the
>> their stdev. Thank you..,
>>
>> Cheers
>>
>>
>> --
>> Regards,
>> Dr. Verena.
>> School of Marine and Atmospheric Sciences
>> Stony Brook University
>> homepage: http://www.somas.stonybrook.edu/
>>
>>
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>> ncl-talk mailing list
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>>
>>
>

--
Regards,
Dr. Verena.
School of Marine and Atmospheric Sciences
Stony Brook University
homepage: http://www.somas.stonybrook.edu/
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