re: #39 VioletTiger

The reason I use SCAMS as a reference point is that it is basically the same instrument as the present MSU. You get your sea ice extent from the microwave reflectivity of the surface in the window channel someplace a bit over 30 GHz away from the 22.235 GHz H2O line and the 50-70 GHz O2 complex. You use the 22.235 channel to take out the water vapor column, although this is not all that important in dry areas like the arctic. The window channel is the channel, btw, that has gone south on the current instrument according to my understanding. The chances of getting the SCAMS data is probably little or none. I doubt they ever transferred it off of the 9 track tape, and the original tapes are probably totally unreadable at this point due to bleed through.

The bottom line is that we probably know less about what the real extent is of the sea ice in 1979 than we pretend to. There is probably some DMSP data lurking someplace (Defense Meteorological Space Program) that was the forerunner of the MSU, but finding that one would be tough too.

Given that the character of the ground stations has changed due to heat islands and all the rest, I am not sure we can say a lot with any real conviction. There is more to this process than taking a dataset of observations. There is the process of qc on that dataset which appears to have a spotty record over time.