An odd twist has developed in the past week regarding some data sets that surfacestations.org volunteers have been using to look at individual stations. The data has changed on NASA's GISS website with no notice whatsoever.
My first indication that something changed came from surfacestations.org volunteer Chris Dunn who wrote to me complaining that one of the sites he'd recently surveyed, Walhalla, SC had been greatly adjusted at GISS for no good reason that he could ascertain, since the site is pristine by climate monitoring standards, and has not gone through any significant changes in the past, and has been operated at the same location (by the same family) since 1916. He wondered why NASA would have to adjust the data for a "good" station. The way I view it, shouldn't good data stand on it's own? That was September 7th. He was using data from NASA GISS published on 8/28.
So he continued to look at the data, and the site. The on Sept 11th he noticed a change when he downloaded the data again. Something had changed, the data was different. Not only the adjusted data but the "raw" data too.
Steve McIntyre of Climate Audit has a complete review at: http://www.climateaudit.org/?p=2077 where he traces data back to Detroit Lakes, MN the station that started this all. See my original post on this: http://www.norcalblogs.com/watts/2007/08/1998_no_longer_the_hottest_yea.html
This set other people into motion looking at the NASA GISS data sets. The conclusion? NASA published new raw and adjusted data on their website with no formal or informal notice. I don't know what to make of this, by I think perhaps this could be a breach of the Data Quality Act. At the least, it flies in the face of accepted scientific courtesy, where if you publish data sets being used by researchers worldwide, scientific courtesy would dictate that you at least place notice of such a change, otherwise there can be a domino effect for hundreds of research projects that use the data. Which would cause researchers to wonder why things don't look the same anymore and begin searching for answers. Well that is exactly what happened here. We had a citizen trying to figure out why a climate site with good data was "adjusted", and then the data changed right in the middle of him looking at it.
Whether this was accidental or intentional I cannot say, but it certainly does not look good coming on the heels of NASA GISS's most recent issue of a mistake causing a revision of our temperature history on August 8th. We deserve better accounting than this when so much hinges on this data.
Let's give NASA and Hansen the benefit of the doubt and see what they have to say about it.
UPDATE: NASA has posted today, their explanation which you can read here: http://data.giss.nasa.gov/gistemp/ Note that this notice appears a full week after the data changed (about 9/10) and only after there was discussion of the issue on blogs such as Climate Audit over the weekend. Why would NASA GISS not announce the change at the same time the data did, particularly when the announcment of the change ammounted to one small paragraph?