Re: a modest proposal [was: Re: [asa] Phil Jones Stepping Down..]

From: Rich Blinne <rich.blinne@gmail.com>
Date: Tue Dec 08 2009 - 14:21:18 EST

In order to help people do their own analysis I'll give an example how this
is done with Glenn's best current argument, The European Themometer post.
One of my questions I ask is the literature being referenced.

In Glenn's case he didn't and just started wildly speculating. Methods that
have been used to correct temperature data are described in more than a
dozen peer-reviewed scientific papers by NOAA's National Climatic Data
Center (NCDC). A series of data corrections was developed to specifically
address potential problems in trend estimation of the rates of warming or
cooling in the USHCN. They include:

1. Station moves and instrumentation changes (Karl and Williams 1987, Quayle
et al. 1991),
2. changes in observing practices, such as observing time changes (Karl et
al. 1986), and
3. urbanization (Karl et al. 1988).

The relevant literature for the corrections of the NCDC data is here:

 Karl, T.R., H.F. Diaz, and G. Kukla, 1988: Urbanization: its detection and
effect in the United States climate record, *J. Climate*, *1*, 1099-1123.
Karl, T.R., C.N. Williams, Jr., P.J. Young, and W.M. Wendland, 1986: A model
to estimate the time of observation bias associated with monthly mean
maximum, minimum, and mean temperature for the United States, *J. Climate
Appl. Meteor.*, *25*, 145-160.
Karl, T.R., and C.N. Williams Jr., 1987: An approach to adjusting
climatological time series for discontinuous inhomogeneities. *J. Climate
Appl. Meteor.*, *26*, 1744-1763.
Menne, M.J., and C.N. Williams, Jr., 2005: Detection of undocumented
changepoints using multiple test statistics and composite reference series.
*J. Climate*, *18*, 4271-4286.
Menne, M.J., and C.N. Williams, Jr., 2007: Homogenization of temperature
series via pairwise comparisons. *J. Climate*, in review
Peterson, T.C., 2006: Examination of potential biases in air temperature
caused by poor station locations, *Bull. Amer. Meteor. Soc.*, *87*,
1073-1080, DOI:10.1175/BAMS-87-8-1073
Quayle, R.G., D.R. Easterling, T.R. Karl, and P.Y. Hughes, 1991: Effects of
recent thermometer changes in the cooperative station network, *Bull. Amer.
Meteor. Soc.*, *72*, 1718-1724.

The longer and older a series is the more there needs to be correction. The
oldest themometers are in (drum roll please) Europe and the Northern
Hemisphere. Also, Europe is more urban and corrections need to be made for
urbanization. You can even see this when you compare the two maps on Glenn's
site. The areas that are the most different between the maps AND need the
least correction have an uncorrected color of gray. The mapping software
creates a gray for the uncorrected data because in 1880 there was no station
to get data from. By chosing such an old start point, Glenn made the
European data look bad because they were using -- by necessity -- 19th
Century technology. The Antarctic data needs to be heavily corrected for a
different reason, there are so few thermometers on the continent (see Menne
and Williams 2005 and Karl and Williams 1987).

So, if I were a peer reviewer I would send it back with the following
comment. Interesting observation. Please repeat the comparison with a
temporal comparision of the corrections rather than a spatial one. Also,
choose a sufficiently modern start point so that stations exist for all the
compared regions.

Rich Blinne
Member ASA

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Received on Tue Dec 8 14:21:43 2009

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