The “before 1992 / after 1992 stations” from “The 1990s station dropout does not have a warming effect”:

The short trends are done with the last 30 years of data for each series (which since one series ends in 1991, is a different period for each). Notice how similar the recent trends are.

Reprising the Urban Adjustment post:

I don’t think I’ve done a combined land and ocean chart comparing hemispheres for the blog before, but here it is now:

Nick Barnes added the calculation of R² whilst I was writing this post, causing me to redraw all the charts.

Nick has also been exploiting ccc-gistemp’s new parameters.py module, and did a run with the somewhat experimental 250km smoothing rather than the traditional 1200km smoothing. The parameter is named gridding_radius and it affects gridding in Step 3; setting it to 250km essentially reduces each station’s influence to very roughly the size of the cell used in gridding.

The effect on the trends is most visible in the Northern Hemisphere:

Trends are just one minor example of the way in which the ccc-gistemp code can be continuously improved. We don’t just draw trends for one graph, we improve the code so that all graphs can have trends.