Update Fri Jan 29 2.56 pm (East Aust Time) Big Oops. Programming error.
It is surprising that such a simple program could have a programming error. But there was a memory overflow, and it had a big effect on the results.
With that corrected, there is indeed a rise in station mean temps. The new graph is here. I should emphasise that the plot is of "naive" means - just averaging all readings for each year, including duplicates.
The new plot is like that on p 14 of the d'Aleo/Watts report, and different from that on p 11.
The revised R code I used to calculate and plot this example is here
The new report of d'Aleo and Watts, trumpeting calculations of E.M.Smith, makes much of a supposed shift of GHCN stations to warmer areas as an alleged source of warming. Indeed, it is full of accusations that this is done with fraudulent intent.
Of course, anomaly calculations wouldn't show warming for that reason. But is the station set actually warming?
I did a simple calculation. Just the average temperature of all stations in the GHCN set v2.mean, for any year. You might expect a small rise reflecting global warming. But if there is nett movement of stations to warmer climes, that should show as a bigger effect.
Here's the result, plotted from 1950. The trend is actually down.
The R code I used to calculate and plot this example is here
Update 29 Jan. I investigated the downspike about 2006. It's caused by some stations returning a lot of missing months, which yields erratic results. So I put a screen in the program requiring at least 9 months of data before a station could contribute to the year's average. It didn't change the overall picture, but did eliminate the spike at 2006.
Following a suggestion of Carrot Eater, I checked the v2.mean adjusted file. The results, not very different, are here .