from: Phil Jones <p.jonesatXYZxyz.ac.uk>
subject: Re: Land/Ocean
to: Tom Wigley <wigleyatXYZxyzr.edu>
Still no sight of the HC paper on the 1945-60 adjustments, so nothing also on the
possible recent changes in SSTs.
All just confirms what is said in the CC paper that SSTs are what's really important for
On Jim Hurrell's paper about the development of a new SST and Sea-Ice Edge dataset, it's
not clear whether this has been used by any Reanalysis yet. It hasn't by ERA-INTERIM. What
was used here is in that paper I sent you a few weeks ago by Adrian Simmons. Also clear
that you need to put increases in radiative forcing from greenhouse gases into these
reanalyses. I'll contact Gil Compo again to find out what they used.
I realized over the weekend that what GISS use for SST in their analysis is the same as
what was used to force ERA-40 and NCEP. ERA-INTERIM changed this slightly but only in the
last few years.
At 16:17 08/11/2009, Tom Wigley wrote:
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I have sorted some of this out -- see attached. In fact, this
is very interesting and kinda cool. The ocean cooling is exactly
0.2C more than the land cooling ('exact' is partly a fluke of
course). So this is a nice check on the ocean error. Has this been
pointed out before?
Also, the fact that land warming has only begun to accelerate
relative to the ocean over the past 30 years fits beautifully
with the suggestion Sarah and I made in 1987 that the early
20th century warming was a YHC effect. And this all fits with
the minimal effect of the Sun for this period, as I have noted
before. I do not this this is generally appreciated.
I mentioned Hurrell. I'll attach his paper. It is strange
(sloppy?) that he does not compare the NCAR data set with HadCRU
or HADSST2. We do need to mention this paper in our Clim Ch
ms. In fact, we should compare his data with our data.
Here is my text on the early 20th century warming ...
"This small solar contribution applies equally to the early 20th century (191040)
warming. The observed warming over this interval is about 0.5oC (see Figure 1 and Table
1), while the solar-induced change is either close to zero, perhaps even a cooling
(assuming no secular TSI component), or a warming of about 0.02oC with a secular
component (Figure 8). At most, therefore, the solar contribution to early 20th century
warming is about 4% (even when one assumes a high value for the climate sensitivity).
This minimal solar effect has been noted previously by Foukal et al. (2004). So, what
caused the early 20th century warming? A possible explanation is that it is the result
of a major increase in the rate of formation of NADW (Wigley and Raper, 1987), an idea
that is supported by the pattern of warming which is a maximum in the North Atlantic
(Schlesinger and Ramankutty, 1995). We noted earlier that the fact that this warming is
similar for the land and the ocean (in fact, the 1910 to 1940 trend over the ocean is
greater than over the land) suggests that it is not externally forced (since this would
normally lead to warming over the land that was greater than over the ocean), and that
it originates in the ocean. This also helps to explain why the land/ocean warming
differential that one would expect as a consequence of external forcing has only become
evident over the past three decades."
Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) 1603 592090
School of Environmental Sciences Fax +44 (0) 1603 507784
University of East Anglia
Norwich Email p.jonesatXYZxyz.ac.uk