Your comments about these data are correct and I have taken the trouble to download them. Some immediate observations:

1. These data are secondary and without exception computed values from primary data. To annotate their data columns as “observed temperature anomalies” or acronyms representing such, is categorically wrong.

Comment: There is no such thing as an observed temperature anomaly – there are only observed temperatures, which might be maxima or minima, or in between, depending on when the observer decided to record the data. Having worked in the bush, where some meteorological stations were located and observing the recording habits of the people assigned to do the job, one tends to be a tad cynical over the accuracy of recorded data. (I assume the various bodies responsible for these human frailities factor this into their summations of the daily data).

Temperature anomalies, if I understand the concept, are computed after the observation is made and incorporate many assumptions about what is considered the “baseline” about which computed anomalies vary. There is, therefore, no such thing as an “observed temperature anomaly”.

2. All the temp anomalies seem to vary around a mean of zero, and for the NHMean data set, Grapher provided these statistics.

Number of values 596
Sum -17.6284124
Minimum -0.346741
Maximum 0.3734786
Mean -0.029577873
Standard deviation 0.12870645

The time period for these data is 1400 to 1980.

From 1980 we have the following data:

Obviously 1981 to 1994 are arbitrarily taken as the base line, but on cursory inspection, how can column 3 be derived from “0″?, if the rest of the data are involved in the calculation (if at all).

1980 0.1213765 0.2128329 0.216799 0.025954 0.3122215 -0.0694686
1981 0 0.3820948 0 0 0 0
1982 0 0.1555486 0 0 0 0
1983 0 0.3991676 0 0 0 0
1984 0 0.1024897 0 0 0 0
1985 0 0.0390147 0 0 0 0
1986 0 0.1980824 0 0 0 0
1987 0 0.3586828 0 0 0 0
1988 0 0.412646 0 0 0 0
1989 0 0.3791483 0 0 0 0
1990 0 0.5740622 0 0 0 0
1991 0 0.4239854 0 0 0 0
1992 0 0.27 0 0 0 0
1993 0 0.3 0 0 0 0
1994 0 0.45 0 0 0 0

Clearly no one was measuring temperature at 1400 AD, (although I should mention my ancestors were offically recorded to be active at that time at Deventer in the Netherlands), and since precision to the degree of measuring temperature to a decimal fraction of a degree was only achieved in the electronic era, other factors being equal, one must totally reject these data as irrelevant, since their variation is well within the precision of the instrumentation of the time.

Consequently these temperature anomalies are essentially statistical artefacts.

Apart from that no one seems to have published raw “mean temperatures” of a particular location, or globally.

Is this because physically input equals output, and that whatever happens on the plus side, is balanced on the minus side, so that the system is overall in equilibrium?

Steve: OK.