By lifting and replanting the legs as needed to remain on the surface. After so many years of combatting the burial of the South Pole researh stations, they finally placed the facility on legs to remain above the surface. Think of it like a spider who can grip the surface when needed, and lift the legs as needed to reposition them on the surface. Future AWS designs may look more like an interplanetary lander with spider like legs. By digital camera and remote command, they would operate the legs to maintain position on the surface.

It appears that Jon objects to Steve’s use of financial metaphors and parallels in the accounting of station data. If so, it’s bizarre, since the whole point of this blog(and Steve will please correct me if I have it wrong) is to audit, in the business sense, the data, and the statistical means & methods used in climate research.

Of course, Jon could eliminate the confusion by clearly stating his objection.

In the methods section it is apparent that the sparse data for the Antarctica was in-filled using the RegEM spatial algorithm using iterations over time of the covariance of the distant weather station temperatures. It is does not say directly how the gaps in the weather station temperature reports are handled but I suspect that that is handled by RegEM also. The paper refers to RegEM being used on the reconstructed fields and separately of the temperature field.

I think the authors used the satellite IR derived and AWS weather station temperatures with the more extensive coverage that they present in order to build two reconstructions using RegEM algorithms and those sparser but longer reporting stations. These reconstructions are calibrated and verified in the 1982-2006 time period. Evidently that reconstruction model is used along with the temperature data from the sparser and longer lived stations to reconstruct the whole of the Antarctica going back to 1957 (which is the when many of the sparser stations started reporting).

The method of the reconstruction in in-filling the interior temperatures of Antarctica depends critically on the correlation of temperatures over long distances. What frustrated me here was that I did not see in the paper how this was demonstrated or how well the correlations held up over time. Also not covered in detail was the infilling of temperature gaps over time. In my mind demonstrating that the correlations holding up over time within rather narrow limits is critical in extending the reconstruction back from 1982 to 1957.

In order to use the IR data, a cloud cover masking technique had to be used in an attempt to remove the effects of clouds interfering with the satellite view of the ground. I would suspect that this technique presents the greatest source of uncertainty in the reconstruction. The authors appear to have the some reservation judging by their comments. Also they selected a threshold value of retaining data as not being cloud contaminated of 10 degrees C and because it “…produces the best validation statistics in the reconstruction procedure.” That to me would appear to be a clear cut case of data snooping. The original attempts (Comiso 2000) at using these masking techniques resulted in a colder Antarctica, but one that the Steig paper authors claim would not be consistent with their reconstruction.

Finally I find problematic the Steig authors reference to a warming Antarctica from 1957-2006 with little or no references that I could find in the paper to the more recent years trends (1970-2006) and what a trend might be anticipated to look like when the estimated warm period between 1935-1945 was included in the discussion. They say nothing to forewarn of a 50 year temperature trend being critical to start dates when considering decadal natural climate cycles.