Dear Bert Gunter and Mathew Guilfoyle,
Thanks for the reply.
I also agree with you. But that is the actual slope of the straight line
connecting from the first estimated value to last estimated value ( like
dy/dx slope). I tried in that way also, but I couldn't replicate the
results as given in that Box 2.2, Table 1 and Figure 1. I can replicate
the line plot as in Box 2.2, Figure 1 (a) (to verify my input data is the
same as in Figure 1 (a)).
You can see my plot here:
https://drive.google.com/file/d/14WDFFW5J69WvxnhbfdcOZKvGRk6HUWVn/view?usp=sharing
I have attached my code and data (as NetCDF file) along with this mail.
input Data (only 32Kb) :
https://drive.google.com/file/d/1Wt5sjVhWmjhRWOfdc6elUzwOvifRk-OI/view?usp=sharing
code:
https://drive.google.com/file/d/1r5mg1vcNmDCIf19jnMUAFEiLNOLKQiKq/view?usp=sharing
output figure:
https://drive.google.com/file/d/1bEXWCB-H5doVKXO8i_FLO7KZMW3qc9Cw/view?usp=sharing
Sincerely,
Dileepkumar R
On Tue, Aug 11, 2020 at 11:41 PM Mathew Guilfoyle <mrguilfoyle at
gmail.com>
wrote:
> Looking at the report (specifically the legend for the table) I think all
> they have done is take the difference between fitted temperatures (given by
> linear regression or the GAM) at the start and end of each period (e.g. in
> 1901 and 2012), and then calculate the average change per year.
>
> In a way it ?linearises? the spline trend but I don?t think it?s really
> valid. It just highlights how poorly a (simple) linear regression can fit
> a very non-linear trend.
>
> > On 11 Aug 2020, at 13:21, Dileepkumar R <dileepkunjaai at
gmail.com> wrote:
> >
> > ?Dear All,
> >
> > I am trying to estimate the non -linear trend value from smooth spline
> > trend fit (using the generalized additive model (GAM)).
> >
> > I want to estimate the trend value from a temperature dataset (spatial
> > averaged annual meantime from 1906 to 2005) as given in the Box 2.2,
> Table
> > 1 in the attached Google doc pdf. (That pages are from IPCC
Assessment
> > Report 5 chapter 2
> > <
> https://www.ipcc.ch/site/assets/uploads/2017/09/WG1AR5_Chapter02_FINAL.pdf
> >,
> > page number 21-22 )
> >
> > I do not understand how they estimate the single value trend with 95%
> > confidence interval from a time-series data as given in the Box 2.2,
> Figure
> > 1. Is there any easy way to extract the trend value using mgcv
library
> of
> > R.?
> >
> > Google Doc Link:
> >
>
https://drive.google.com/file/d/1z3XLW-154dsZE6GrvQ4rH_fev9lqdsho/view?usp=sharing
> >
> > Thank you all in advance
> >
> > Dileepkumar R
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> > PLEASE do read the posting guide
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> > and provide commented, minimal, self-contained, reproducible code.
>
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