Catching up

I’ve been spring cleaning.

For too long I have neglected ccc-gistemp (our clear rewrite of GISTEMP). For a while now it has not been possible to run it. The problems were mostly due to finding the right Sea Surface Temperature (SST) file. The old file was called SBBX.HadR2 (a combination of Hadley ISST and Reynold’s Optimal Interpolation v2). GISS withdrew this file in favour of SBBX.ERSST which is Smith et al’s 2008 Extended Reconstruction

In the final stages (Step 5) of ccc-gistemp, SSTs from the ocean file are combined with temperature anomalies from land-based meteorological stations to produce zonal means that are then averaged into hemispherical and global means. The choice of which dataset to use for SSTs is not completely straightforward, there are different groups with different ways to assimilate all the available observations. Hansen et al’s 2010 paper “Global Surface Temperature Change” does a good job of comparing some of the available options.

So now we’ve caught up with GISS and can do once again do an analysis of combined Land and Ocean Temperatures:

Global Land-Ocean Temperature Index

I’ve also moved the code to github, which is a much nicer place and you should move there too.

While spring cleaning I noticed that ccc-gistemp had accumulated a few tools and bits of code that had less to do with ccc-gistemp and more to do with Global Historical Climatology Network. I’ve moved those into their own ghcntool repository.

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