Roger wrote:
The message
from Terry Fields contains these words:
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.
An interesting point, perhaps the relative stability of the Antarctic
ice-cover is the reason that much of the discussion is about the
Arctic - which has the benefit of being fairly close to populated
centres, etc, allowing easier coverage, on the ground or in the air,
that its sister Pole.
which seems unhappy with some aspect or other of the Hadley Centre's
work.
You mean the side issue posted by A Skepic esq.?
I didn't read the discussion, as I wanted to stick as closely as
possiblle to the original comments, so I#'ve no idea what Mr Skepic
said....
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.
Given the 'can of worms' that the information abourt satellite data
appear to have uncovered, this is perhaps an observation of note.
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.
Well, I'm not so sure. One problem that might arise is that the
models, which take something like a thousand different inputs, and
which to some extent then get tweaked in order to avoid wild swings in
output - implying great sensitivity to input conditions - have not
taken this into account. I know extremely little about chaotic systems
modelling, but what does come across is how tiny adjustments to the
initial conditions (of which there are so many) have this
disproportionate effect on output.
Data-collection methods such as satellite and ground observations will
take readings that incorporate the effects of these currents, whatever
the scale of their effect. The comment that these currents "may be the
discovery of the decade" suggests at the very minimum they are worthy
of study, and should certianly be considered for inclusion in the
modelling when more is known about them. After all, the discrepancies
between the data and the models predictions is currently leading to a
great deal of discussion; perhaps everyone is looking in the wrong
direction.
"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.
Isn't it just?
On the topic of recent data, I found a reference he
http://www.paulmacrae.com/?p=74 (scroll down to the first two graphs)
which states that the data for one of the graphs we looked at earlier
- the one showing the Temperature Anomaly from ~1861 - 2004 and about
which we exchanged some data-reduction - has now been amended to
include figures up to January 2008, and published by the Met Office.
The author of the reference alleges that the data is not easy to find,
and that none of this new data appears to have been incorporated into
any MetO publication. His conclusion is that the MetO find this
apparent levelling-off in the recent TA figures somewhat inconvenient
to explain. I'm not suggesting I agree with him - or the trend-lines
added to the second graph, for that matter - but it is interesting
that such data is available but seems not to have been used so far.
One could read all sorts of things into that, and we could also
discuss this until we'd thrashed the possibilities to death. Would you
like to continue this interesting debate, or do you think we have
exchanged enough information for now for both of us to mull over? We
must have bored the group's other readers to death. I'm sure that more
data - and TV programmes! - will be along soon for us to pick up where
we left off.