While there inevitably will be groups that base their cautionary
position on worries about either the economy, the environment or both,
the issue here is one in which people cherry pick data and quote mine,
to support a position which science does not support. We find the same
approach amongst some/many creationists who are looking for gaps in
our knowledge as places for God to hide.
In the past asbestos or tobacco companies and their lobbying groups
poured significant amounts of money in promoting 'research' which
doubted the science behind the data. Now we find that Exxon mobile
(and undoubtably others) have poured millions into programs that
support a 'skepticism' towards global warming and the human component.
The science behind global warming is fraught with many unknowns and
many assumptions and yet, most of the data all point to the same fact
which is that human component to global warming is significant. Of
course, there will remain controversies within the science about for
instance the satellite readings which historically have shown flat or
decreasing temperatures, contradicting much of the other data sources.
The question then becomes: does one reject the vaste amount of data
because of a minor controversy or does one first search to discover
flaws in the measurements? In the case of the satellite data, science
has caught up and uncovered various sources of bias which, once
removed, lead to a much better match between the various data sources
as well as the models. And thus the minor mystery of why satellite
data underestimated the warming were resolved once corrected for
diurnal biases, biases in the orbits and the warming of the sensors
due to direct solar heating.
In "The Gospel of John"
(http://www.discover.com/issues/feb-01/features/featgospel/) we read
about the work by Christy on satellite data and how he tried to defend
the data against sometimes harsh attacks. Nevertheless, science has
since then discovered that there were significant flaws with the data
correction methods applied.
http://www.meteor.iastate.edu/gccourse/alumni/satellite/satellite.html
Satellite-derived Measurements Agree with Surface Temperature Trends
In 1990, scientists at the University of Alabama-Huntsville (Spencer
et al, 1990) reported that satellite-derived measurements of
tropospheric temperature did not show a warming over the period since
1978 (beginning of the period over which satellite data are available)
and therefore seemed to be in contradiction with warming trends
observed at the earth's surface. Various corrections to satellite data
since the first report have gradually narrowed this discrepancy.
Vinnikov and Grody (2003) report analysis of satellite temperatures
from 1978-2002 and show "a trend of +0.22ºC to 0.26ºC per 10 years,
consistent with the global warming trend derived from surface
meteorological stations." This trend of warming is consistent with
global climate models that ascribe this warming to increases in
atmospheric greenhouse gases.
Correction to Satellite Based Temperature Record Changes Cooling Trend
to a Warming Trend
(c) Eugene S. Takle
A controversy has existed the past several years over whether or not
the earth's atmosphere is warming. Data taken from thermometers near
the earth's surface reveal a quite convincing warming trend of about
0.5 K over the last 100 years. On the other hand, data from Satellites
suggest the lower atmosphere is cooling, not warming. Wentz and
Schabel (1998) report that corrections to satellite-based temperature
measurements are needed to account for the slow decrease in altitude
that satellites normally experience due to drag. Spencer and Christy
(1990, 1992) and Christy et al. (1994) reported a 17-year cooling
trend in satellite (microwave sounding unit, MSU) temperature of -
0.05 K per decade globally at 3.5 km. As the satellite falls toward
earth, its field of view changes and produces a reading representative
of a more limited area. The corrected temperature calculated by Wentz
and Schabel (1998) for the period analyzed by Spencer and Christy is
+0.07 K per decade, which is much more consistent with the observed
rise in global surface temperature of 0.13 K per decade (Houghton,
1996) over this 17-year period.
Wikipedia also has some relevant links
http://en.wikipedia.org/wiki/Satellite_temperature_measurements
<quote>The process of constructing a temperature record from a
radiance record is difficult. The best-known, though controversial,
record, from Roy Spencer and John Christy at the University of Alabama
in Huntsville (UAH), is currently version 5.2, which corrects previous
errors in their analysis for orbital drift and other factors. The
record comes from a succession of different satellites and problems
with inter-calibration between the satellites are important,
especially NOAA-9, which accounts for most of the difference between
the RSS and UAH analyses [13]. NOAA-11 played a significant role in
the August 2005 Mears et al paper [14] identifying an error in the
diurnal correction that leads to the 40% jump in Spencer and Christy's
trend from version 5.1 to 5.2.</quote>
Christy responded to the work by Mears
Correcting Temperature Data Sets
We agree with C. A. Mears and F. J. Wentz ("The effect of diurnal
correction on satellite- derived lower tropospheric temperature,"
Reports, 2 Sept., p. 1548; published online 11 Aug.) that our
University of Alabama in Huntsville (UAH) method of calculating a
diurnal correction to our lower tropospheric (LT) temperature data
(v5.1) introduced a spurious component. We are grateful that they
spotted the error and have made the necessary adjustments. The new UAH
LT trend (v5.2, December 1978 to July 2005) is 0.123 K/decade, or
0.035 K/decade warmer than v5.1. This adjustment is within our
previously published error margin of ±0.05 K/decade (1).
We agree with S. C. Sherwood et al. ("Radiosonde daytime biases and
late-20th century warming," Reports, 2 Sept., p. 1556; published
online 11 Aug.) that there are significant, progressively colder
biases in stratospheric radiosonde data, as we and others have noted
(1, 2). We further agree that many daytime radiosondes are plagued by
spurious cooling in the troposphere as well (3). However, there are
also instances in which spurious warming occurs in both day and night
soundings. Such a circumstance is not properly accommodated by the
dayminus-night (DMN) procedure, a possibility mentioned by Sherwood et
al. but not specifically addressed. For example, when the
Australian/New Zealand network, prominent in the Southern Hemisphere
in Sherwood et al.'s Report, switched instrumentation from Mark III to
Vaisala RS-80, both day and night warmed approximately 0.4 K [(3),
updated], with tropospheric night readings warming more than day
readings. On the basis of this relative difference, the DMN method
assumes that a correction for spurious cooling should be applied, when
in fact the real error is large and of the opposite sign.
DMN values are useful indicators for pointing out radiosonde changes,
but they are often not useful in assessing magnitudes and in this case
overestimate the trend. Further, the DMN-adjusted tropospheric trend
for 1958-97 of 0.253 K/decade for the 75% of the globe south of 30°N
is more than 2.5 times that of the surface (0.092 K/decade) and thus
very likely to be spuriously warm. [Note that B. D. Santer et al.
("Amplification of surface temperature trends and variability in the
tropical atmosphere," Reports, 2 Sept., p. 1551; published online 11
Aug.) indicate a ratio less than 1.4.] Direct, site-by-site
comparisons between radiosondes and UAH LT data at 26 U.S.-controlled
stations (nighttime only) from tropics to polar latitudes yield a
difference in trends of less than 0.03 K/decade, showing consistency
with the more modest UAH LT trends (1) [(3), updated through 2004].
John R. Christy*
Earth System Science Center
University of Alabama in Huntsville
Cramer Hall
320 Sparkman Drive
Huntsville, AL 35899, USA
Roy W. Spencer
Earth System Science Center
University of Alabama in Huntsville
Cramer Hall
320 Sparkman Drive
Huntsville, AL 35899, USA
and Mears responded
Science 11 November 2005: Vol. 310. no. 5750, pp. 972 - 973
<quote>Response
Once we realized that the diurnal correction being used by Christy and
Spencer for the lower troposphere had the opposite sign from their
correction for the middle troposphere sign, we knew that something was
amiss. Clearly, the lower troposphere does not warm at night and cool
in the middle of the day. We question why Christy and Spencer adopted
an obviously wrong diurnal correction in the first place. They first
implemented it in 1998 in response to Wentz and Schabel (1), which
found a previous error in their methodology: neglecting the effects of
orbit decay.</quote>
The work by Mears reports
Originally published in Science Express on 11 August 2005
Science 2 September 2005:
Vol. 309. no. 5740, pp. 1548 - 1551
DOI: 10.1126/science.1114772
The Effect of Diurnal Correction on Satellite-Derived Lower
Tropospheric Temperature
Carl A. Mears and Frank J. Wentz
Satellite-based measurements of decadal-scale temperature change in
the lower troposphere have indicated cooling relative to Earth's
surface in the tropics. Such measurements need a diurnal correction to
prevent drifts in the satellites' measurement time from causing
spurious trends. We have derived a diurnal correction that, in the
tropics, is of the opposite sign from that previously applied. When we
use this correction in the calculation of lower tropospheric
temperature from satellite microwave measurements, we find tropical
warming consistent with that found at the surface and in our
satellite-derived version of middle/upper tropospheric temperature.
Based on all these new data, Science reports in 2005
Science 2 September 2005:
Vol. 309. no. 5740, p. 1453
DOI: 10.1126/science.309.5740.1453b
Prev | Table of Contents | Next
This Week in Science
Some reconstructions of recent warming in the troposphere based on
satellite data have indicated that the troposphere has warmed since
1979 (when the data were initially collected) at a rate considerably
less than that, which should be expected from surface temperature
measurements. Three studies (all published online 11 August 2005)
reassess these data and reconstructions in favor of the surface
temperature trends. Mears and Wentz (p. 1548) identify an error in the
diurnal correction that has been applied to the satellite data, and
derive a physically consistent one of the opposite sign, whose
application brings into agreement a newer reconstruction of
tropospheric warming, model calculations, and surface temperature
measurements. Sherwood et al. (p. 1556) show that a spurious temporal
trend was introduced into tropospheric temperature profiles recorded
by radiosondes through changes in instrumentation made over time that
involved solar heating of the instrument above ambient temperature.
Correction for this bias brings many of the radiosonde data into
better agreement with models and the surface temperature record,
particularly in the tropics, where the disagreement between surface
and expected tropospheric temperatures was most pronounced. Santer et
al. (p. 1551) examined patterns of the amplification of surface
temperature trends in the tropical troposphere using 19 different
models. They show that the reconstructions used to argue that the
troposphere was not warming are inconsistent with our understanding of
the physical processes that control the vertical temperature structure
of the atmosphere (the lapse rate).
Real Climate reports
http://www.realclimate.org/index.php/archives/2005/11/more-satellite-stuff/
And the report at
http://www.climatescience.gov/Library/sap/sap1-1/public-review-draft/default.htm
Temperature Trends in the Lower Atmosphere: Steps for Understanding
and Reconciling Differences Public Review Draft of Synthesis and
Assessment Product 1.1
and the final report
http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm
released in may 2006
The report lays to rest much of the "controversy"
According to the published report, there is no longer a discrepancy in
the rate of global average temperature increase for the surface
compared with higher levels in the atmosphere. This discrepancy had
previously been used to challenge the validity of climate models used
to detect and attribute the causes of observed climate change. This is
an important revision to and update of the conclusions of earlier
reports from the U.S. National Research Council and the
Intergovernmental Panel on Climate Change.
"This synthesis and assessment report exposes the remaining
differences among different observing systems and data sets related to
recent changes in tropospheric and stratospheric temperature," said
Chief Editor Dr. Thomas Karl, director of NOAA's National Climatic
Data Center. "Discrepancies between the data sets and the models have
been reduced and our understanding of observed climate changes and
their causes have increased. The evidence continues to support a
substantial human impact on global temperature increases. This should
constitute a valuable source of information to policymakers."
Case closed I'd say. A minor discrepancy, cherry picked by some to
argue against global warming, has been resolved after the data had
been corrected appropriately. Will global warming deniers update their
position (and arguments?) based on these new facts?
Christy was a lead author of the report's executive summary which reads
<quote>According to the published report, there is no longer a
discrepancy in the rate of global average temperature increase for the
surface compared with higher levels in the atmosphere. This
discrepancy had previously been used to challenge the validity of
climate models used to detect and attribute the causes of observed
climate change. This is an important revision to and update of the
conclusions of earlier reports from the U.S. National Research Council
and the Intergovernmental Panel on Climate Change.
"This synthesis and assessment report exposes the remaining
differences among different observing systems and data sets related to
recent changes in tropospheric and stratospheric temperature," said
Chief Editor Dr. Thomas Karl, director of NOAA's National Climatic
Data Center. "Discrepancies between the data sets and the models have
been reduced and our understanding of observed climate changes and
their causes have increased. The evidence continues to support a
substantial human impact on global temperature increases. This should
constitute a valuable source of information to policymakers."</quote>
The report also cautions that there remain some minor issues
<quote>Tropical Temperature Results (20°S to 20°n)
• Although the majority of observational data sets show more warming
at the surface than in
the troposphere, some observational data sets show the opposite
behavior. Almost all model
simulations show more warming in the troposphere than at the surface.
This difference be-
tween models and observations may arise from errors that are common to
all models, from
errors in the observational data sets, or from a combination of these
factors. The second
explanation is favored, but the issue is still open.
</quote>
Next... the Exxon report in more detail.
On 1/6/07, Merv <mrb22667@kansas.net> wrote:
> "There are two kinds of people in the world: those who say there are
> two kinds of people in the world, and those who don't." ---???
>
> In that spirit, and since we all like to have pegs on which to hang our
> hats, here is your weekly oversimplification from merv:
>
> The controversy between those who choose their cautionary status with
> reference to economy and those who choose their cautionary status in
> regards to environment also seems to loosely fit another dichotomy.
> The former harbor mistrust towards government and hearken instead to the
> private sector as the best keeper of the public good (often citing
> blundering inefficiencies of the public sector as compared to the
> private). They trust the profit motive to keep the public best
> interests in mind at some level.
>
> The latter are much more trusting of the public sector -- and with good
> reason. While they can't deny the blundering ineptitudes of many
> government programs, at least, the powers behind them (to the dwindling
> extent that those can stay free of corporate control) are, in theory,
> more accountable to the voter at large (i.e. one person = one vote
> rather than under the private sector where 1$ = 1 vote). So I have to
> agree with Joel Bakan ("The Corporation") as I ponder who I would rather
> trust: the blundering politician who at least has a chance of
> having some public good in mind and pushing clumsily in that
> direction; or the multinational corporation which, with
> breathtaking efficiency rapes and pillages our communities and our
> environments in brilliantly run programs which, at bottom, are designed
> to separate you from your money in the present and immediate future.
> ---and that is the ONLY final motive any corporation can legally have in
> its accountability to its stockholders (despite what green looking ads
> would have you believe). And to those who say that corporations are
> still constrained by law, Mr. Bakan shows that even that is an
> illusion. Even their choice to follow any given law is only another
> cost-benefit analysis. "Will our profits justify our risking
> expenditures with fines and lawsuits? --- or how likely is it we'll
> even be caught?"
>
> Lord knows I'm no fan of big government, and powerful corporate
> lobbyists have blurred the distinction between public and private almost
> beyond discernment. But I'm even less of a fan of huge corporations.
> Yes, they are good! But it is WHAT they are good at that worries me.
> Between the brilliant pirate or the clumsy good Samaritan, I will take
> the latter any day. And while politicians may be motivated by the next
> election to say whatever people want to hear, they probably stand a
> better chance of showing occasional fits of moral courage and
> leadership, than the average CEO stands of escaping the enslavement
> driving him to the next $. My apologies to the multitude of exceptions
> to all this that no doubt exist. I know that I'm biting the hand that
> feeds me. But truth stands apart from and irrespective of that
> obligatory gratitude.
>
> --merv
>
>
>
> To unsubscribe, send a message to majordomo@calvin.edu with
> "unsubscribe asa" (no quotes) as the body of the message.
>
To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Sat Jan 6 17:30:46 2007
This archive was generated by hypermail 2.1.8 : Sat Jan 06 2007 - 17:30:46 EST