One of the things making the rounds with the "skeptics" is the dramatic reduction in the number of surface stations after the 1980s which the "skeptics" allege/imply is evidence of cherry picking stations that show the most warming.
Dave recently posted an example here:
http://www.astromart.com/forums/viewpost.asp?forum_post_id=697619&poll_id=&news_id=&page=
linking to this from D’Aleo at IceCap:
http://icecap.us/images/uploads/NOAAroleinclimategate.pdf
Here's a chart from that document showing the dramatic decline in the station count:
and makes the charge that:
The data is then used for estimating the global average temperature and for initializing climate models. Interestingly the very same often coolest stations that were in last two decades deleted from the world climate network were retained for computing the average temperature base periods for each grid box. This also would indicate a deliberate attempt to create a warm bias on the part of NOAA because in calculating the average temperatures in this way it would ensure that the global average temperature for each month and year would now show a positive temperature anomaly.
The world’s surface observing network reached its golden era in the 1960s to 1980s with more than 6000 stations worldwide providing valuable climate information. It dropped rapidly to 1500 around 1990.
Is this some new revelation they have uncovered?
Well, if D’Aleo had Read The Fine Manual from NOAA published over 12 years ago in 1997 they might have found this:
(solid line are stations with mean temps and dashed line are those with min/max temps)
D’Aleo has uncovered a secret that was clandestinely hidden in the publications of the Bulletin of the American Meteorological Society
"An Overview of the Global Historical Climatology Network Temperature Database"
http://www.ncdc.noaa.gov/oa/climate/research/Peterson-Vose-1997.pdf
where we learn that:
A time series for a given station can frequently be obtained from more than one source. For example, data for Tombouctou, Mali, were available in six different source datasets. When "merging" data from multiple sources, it is important to identify these duplicate time series because 1) the inclusion of multiple versions of the same station creates biases in areally averaged temperature analyses, and 2) the same station may have different periods of record in different datasets; merging the two versions can create longer time series.
The goal of duplicate station elimination is to reduce a large set of n time series (many of which are identical) to a much smaller set of m groups of time series that are unique. In the case of maximum and minimum temperature, 8000 source dataset time series were reduced to 4964 unique time series.
AHA! so NOAA admits that they maliciously removed over 3,000 duplicated stations! The scurrilous reasons for removing the rest of the station data is there too!
[/sarcasm]
If D’Aleo had RTFM from NOAA, he'd see that NOAA laid out the boring reasons 12 years ago for why station data was removed. But hey, that's not as much fun as cooking up conspiracies for the gullible now is it?
