[19239] in s-news-athena
[S] References for late discovery of hole in the ozone layer due to "outlier" deletion
daemon@ATHENA.MIT.EDU (STEVEN.P.MILLARD)
Thu Sep 16 13:46:22 1999
Message-Id: <01BF002F.88042860.STEVEN.P.MILLARD@prodigy.net>
From: "STEVEN.P.MILLARD" <STEVEN.P.MILLARD@prodigy.net>
Reply-To: "smillard@probstatinfo.com" <smillard@probstatinfo.com>
To: "S-news (E-mail)" <s-news@wubios.wustl.edu>
Cc: "'Keith Dixon'" <kd@gfdl.gov>, "'Gene Felber'" <gfelber@rxttm.com>,
"'Yonnie'"
<yonnie@statsci.com>,
"'Edward Malthouse'"
<ecm@casbah.acns.nwu.edu>,
"'Christmann, Andreas'"
<A.Christmann@HRZ.Uni-Dortmund.DE>,
"'Elaine Florio'"
<eflorio@jhsph.edu>
Date: Thu, 16 Sep 1999 09:46:50 -0700
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Hello Everyone,
Thanks so much for your quick replies to my query about a reference
citing the delayed discovery of the hole in the ozone layer over
Antarctica due to software that automatically deleted "outliers". Anne
York's response reminded me that NOVA had a program on the ozone hole
quite a few years ago, and now I'm thinking that is where I first heard
about the "outlier" deletion episode.
Thanks to Gene D. Felber for pointing out the URL
http://curriculum.qed.qld.gov.au/kla/eda/ozone.htm which gives a brief
overview of this exact topic!!
Also thanks to Keith Dixon, who wrote:
I believe that the reference is...
Stolarski, R.S., A.J. Krueger, M.R. Schoeberl, R.D. McPeters, P.A.
Newman, and J.C. Alpert. 1986. Nimbus 7 satellite measurements of the
springtime Antarctic ozone decrease. Nature 322:808-811.
On his web page on "DATA QUALITY CONTROL / QUALITY ASSURANCE" Don
Edwards of the Department of Statistics, University of South Carolina
describes it as "One of the most famous data QA/QC blunders occurred
when NASA computers were programmed to delete satellite observations of
ozone concentrations below a specified level, and thus failed to
discover the "ozone hole" over the south pole (Stolarski et al. 1986)."
http://www.lternet.edu/ecoinformatics/guide/edwards.fv4.htm
NASA's fact sheets usually omit any direct reference to the outlier
problem. On one hand, they'll say "Since the launch of the first TOMS
aboard the Nimbus-7 polar-orbiting satellite in 1978, NASA has provided
scientists with reliable, high-resolution daily maps of global ozone
levels." Yet they also note, "The ozone hole was discovered through
British ground-based observations in the mid-1980s, but analysis of
TOMS data indicates it has existed since at least 1979." It is left for
the reader to deduce why the "reliable, high-resolution daily maps"
that NASA was getting since 1978 didn't discover the ozone hole
earlier.
http://pao.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci
/ozonestu.htm
Hope that helps,
----------------------------------------------------------------------
Keith W. Dixon _______ _______ ______ _
E-mail: kd@gfdl.gov (_______|_______|______)(_)
URL: http://www.gfdl.gov/~kd/ Geophysical Fluid Dynamics Lab
Postal Address: NOAA/GFDL, | | (_ | ___) | | | | |
P.O. Box 308, Princeton, NJ 08542 | |___) | | | |__/ /| |_____
------------------------------------ \_____/|_| |_____/ |_______)
Sincerely,
--Steve M.
_____________
| *** | Steven P. Millard, Ph.D.
| * |
| * * * | P robability, TEL: 206-528-4877
| * * * | S tatistics & FAX: 206-528-4802
| * | I nformation E-mail: SMillard@ProbStatInfo.com
| * | Web: www.ProbStatInfo.com
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