1998 no longer the hottest year on record in USA

Here’s a story of scientific investigation and discovery I’m proud to have
had a small part in.Regular readers may remember that I posted about a

climate station in Detroit Lakes MN last week, surveyed by volunteer Don
Kostuch, and cross posted it to the website

http://www.climateaudit.org/?p=1828#comments that had two air
conditioner units right next to it. It looked like an obvious cause and
effect because in 1999 on May 5th, it was determined that the a/c units were
moved off the roof of the radio station where this station resides and moved
them to the ground where the temperature sensor is close by.

Detroit Lakes, MN surveyed by Don Kostuch - Don has
single handedly done almost the entire state of Minnesota!However, some folks on the blogosphere just went, well, a little
ballistic over that assertion. It was a good thing too, because their very
loud and somewhat uncivil complaints led to an examination of this idea: if
its not the a/c units, what then did cause the temperature jump at that
time?

Steve McIntyre, of Toronto operates
www.climateaudit.org and began to
investigate the data and the methods used to arrive at the results that were
graphed by NASA’s Goddard Institute for Space Studies (GISS).

What he discovered was truly amazing. Since NASA does not fully publish
the computer source code and formulae used to calculate the trends in the
graph, nor the correction used to arrive at the “corrected” data. He had to
reverse engineer the process by comparing the raw data and the processed
data..

Here is one of his
first posts
where he begins to understand what is happening. “This imparts an upward
discontinuity of a deg C in wintertime and 0.8 deg C annually. I checked the
monthly data and determined that the discontinuity occurred on January 2000
- and, to that extent, appears to be a Y2K problem. I presume that this is a
programming error.”

He further refines his argument showing the
distribution of the error,
and the problems with the
USHCN temperature data. He also sends an email to NASA GISS advising of the problem.

He finally publishes it
here, stating that NASA made a correction not only on their own web
page, attributing the discovery to McIntyre, but NASA also issued a
corrected set of temperature anomaly data which you can see here:

http://data.giss.nasa.gov/gistemp/graphs/Fig.D.txt

Steve McIntyre posted this data from NASA’s newly published data set from
Goddard Institute of Space Studies (GISS) These numbers represent deviation
from the mean temperature calculated from temperature measurement stations
throughout the USA.

According to the new data published by NASA, 1998 is no longer the
hottest year ever. 1934 is.

Four of the top 10 years of US CONUS high temperature deviations are now
from the 1930s: 1934, 1931, 1938 and 1939, while only 3 of the top 10 are
from the last 10 years (1998, 2006, 1999). Several years (2000, 2002, 2003,
2004) fell well down the leaderboard, behind even 1900. (World rankings of
temperature are calculated separately.)

Top 10 GISS U.S. Temperature deviation (deg C) in New Order
8/7/2007

Year	Old	New
1934	1.23	1.25
1998	1.24	1.23
1921	1.12	1.15
2006	1.23	1.13
1931	1.08	1.08
1999	0.94	0.93
1953	0.91	0.90
1990	0.88	0.87
1938	0.85	0.86
1939	0.84	0.85

Here’s the old order of top 10 yearly temperatures.

Year	Old	New
1998	1.24	1.23
1934	1.23	1.25
2006	1.23	1.13
1921	1.12	1.15
1931	1.08	1.08
1999	0.94	0.93
1953	0.91	0.90
2001	0.90	0.76
1990	0.88	0.87
1938	0.85	0.86

I salute the work of Steven McIntyre, he has now made two major contributions to climate science.
1) Proving how the Mann “hockey stick” used in all Gore’s movie, An Inconvenient Truth, was based on unsupportable data and methods.
2) Proving how yearly temperature anomalies for the USA are based on data that had been processed incorrectly.

Dr. Roger Pielke of the University of Colorado also deserves credit becuase he was the one who encouraged me to pursue the www.surfacestations.org project due to his broad work on land use change and it’s affect on regional and local climate.