The message
from Terry Fields contains these words:
one was a graph of satellite data 'suggesting', to put it mildly, that
planetary temperatures had fallen for a number of years; Data
sources: Hadley Center, University of Alabama
Which graph was that then? I don't recall a single graph I looked at
where the trend was downward.
Can I take it that was not a graph of the original data before they
adjusted for orbital decay?
I had a punt about to find an answer for you, but I kept coming across
references to sea-ice growth of 9 percent in 2007/8. As these were not
scientific papers, but more along the lines of interested parties
exchanging emails and blogs, I mention it for interest only.
You could be right on that 2 million square km is a very large area.
Incidentally Wikipedia has so interesting information on polar ice
including the rather strange notice that the extent includes sea with
only 15% ice.
Seems I was wrong about the antarctic ice. Conditions in the Antarctic
are very different and much of that sea ice there comes and goes on an
annual basis and has been close to or at maximum extent in the recent
past. Arctic summer ice OTOH is mostly (or at least was) at least
several years old.
One such is he
http://wattsupwiththat.wordpress.com...-time-hadcrut/
That graph would appear to be a plot of the value every month unlike the
Met Office Jan graph but leaving aside that steep drop at the end for a
moment the graph does show a generally rising trend. 1998 as always
sticks out like a sore thumb but that is followed by a drop of similar
magnitude to that between Jan 2007 and Jan 2008 so there is some
expectation that the temperature should bounce back..
which seems unhappy with some aspect or other of the Hadley Centre's
work.
You mean the side issue posted by A Skepic esq.?
Another reference he
http://wattsupwiththat.wordpress.com...lobal-metrics/
compares four different estimates of the Temperature Anomaly, all of
which show a (dramatic?) drop in temperature from January 07 to
January 08. Of interest is the statement "The difference between these
metrics is of course the source data, but more importantly, two are
measured by satellite (UAH, RSS) and two are land-ocean surface
temperature measurements (GISS, HadCRUT)", so that would appear to
rule out bias by the satellite measurements.
Another he
http://www.warwickhughes.com/blog/?p=161
That seems mostly about how someone is more than a little unhappy with
Met Office data.
has an interesting mention at No. 8 of ocean currents that have
seemingly been only recently discovered, the impact of which remains
unknown - perhaps bad news for the modellers?
Depends. 40 metres per hour is almost snails pace. If they have a
significant effect they should have been discovered earlier.
Taking a leaf out out your own book, Wikipedia turned up an aritcle on
satellite sensing of temperatures:
http://en.wikipedia.org/wiki/Satelli...e_measurements
Different methods give somewhat different results but they seem in
general agreement the trend has been upward.
For obvious reasons, I fell over laughing when I read this:
"The satellite records have the advantage of global coverage, whereas
the radiosonde record is longer. There have been complaints of data
problems with both records, and difficulty reconciling the
observations with climate model predictions."
The models aren't perfect in the first place and figures from satellites
are derived and thus much more open to accidental error in
interpretation than a thermometer directly reading temperature. So long
as the general agreement isn't down to collusion the more different
methods ending up with similar results the more certain we should be
that they are all on the right track.
It goes on to say:
"The IPCC Fourth Assessment Report Summary for Policymakers states:
"New analyses of balloon-borne and satellite measurements of lower-
and mid-tropospheric temperature show warming rates that are similar
to those of the surface temperature record and are consistent within
their respective uncertainties, largely reconciling a discrepancy
noted in the TAR."
"However, as detailed in CCSP SAP 5.1 Understanding and Reconcilling
Differences, neither Regression models or other related techniques
were reconcilable with observed data. The use of fingerprinting
techniques on data yielded that "Volcanic and human-caused
fingerprints were not consistently identifiable in observed patterns
of lapse rate change." As such, issues with reconciling data and
models remain."
One may make of this what one will, but at the very least one gets the
impression of a certain frisson concerning satellite data and model
predictions that don't agree - perhaps because the latter have not yet
taken account of the newly-discovered ocean currents, but satellite
data, by its nature, would.
You may be happy to know that:
"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 [15]. NOAA-11 played a significant role in a
2005 study by Mears et al. 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.[16]"
....which should at least partly answer your question.
Now that is a right can of worms.
--
Roger Chapman