I have no background in climate science, but I've become interested in explanations of the so-called "global warming hiatus" from 1998-2013. One explanation that people seem to think is convincing comes from Karl et al who, if I understand correctly, say that the apparent hiatus could actually be an artifact of changes the way we calculate sea-surface temperature -- specifically that during that period we moved from primarily boat-based temperature measurements to primarily buoy and Argo float measurements. Since boat measurements are systematically a bit warmer than buoy measurements, the gradual switchover looks like a slight cooling trend when in fact it's just a difference in measurement technique.
I wanted to assess this argument for myself as well as I could, so I thought, if Karl et al are correct, then we shouldn't see evidence of hiatus in land-based datasets then, right? So I went in search of a dataset like NASA's global land-ocean temperature index but constrained to land only. I have found some very granular LST datasets (like this), but I don't think I've got the expertise I'd need to turn them into a yearly global timeseries (e.g. should I just take a straight mean of all the datapoints? Should I be weighing by landmass or seasonality, etc?).
So my question is, does a high-level aggregated yearly mean LST dataset exist? If not, why not? And at a higher level, does my approach to investigating the Karl et al work make sense, and if so has someone who knows what they're doing already done it?
