Maybe because the N Hemisphere has more land mass, it is more open to GISS type inflation?

Oops. This is Satellite. Is the RSS adjusted in any way?

I might as well add my speculations on this pattern, and show I can make up stuff too.
The following assumes these differences are real values and not biases.

Since I have been reading Miskolczi I keep interpreting everything in his framework of global equilibria. In general, the earth is an optimized system for converting short wave radiation into long wave radiation, so little change in overall temperature can be expected from an increase in GHG concentration, but maintainence of optimal conversion
could change global patterns.

One of those equilibria is given by the Virial Theorem. This very general principle states that the potential energy equals the kinetic energy. So it seems to me an increase in GHG forcing could partition between potential energy and kinetic energy, one being overall temperature, and the overall hemispheric temperature difference. In a sense, AGW could be partly ‘absorbed’ into the temperature differential between the hemispheres. The increased slopping about of air over the year is the expression of the increased kinetic energy.

In support of this theory, the increase in differential between the hemispheres is about equal to the increase in global temperatures for the same period – KE=PE.

In ‘A comparison of tropical temperature trends with model predictions’ (International Journal of Climatology, 2007, DOI: 10.1002/joc.1651), Douglass, Christy, Pearson and Singer said that “Much of the Earth’s global mean temperature variability originates in the tropics, which is also the place where the disparity between model results and observations is most apparent.”

In the light of that statement, it’s worth noting that the latest (March) RSS MSU data for the tropics shows an even larger negative anomaly than in the southern hemisphere.

Ian, I hadn’t noticed that comment before. I think the Douglass et.al. observations are some of the most serious challenges to AGW as it is currently understood. Surely the tropical anomaly being lower than the SH anomaly could only be a temporary disequilibrium.

Maybe the more pertinent comparison, in the light of the first part of the Douglass et al observation (‘Much of the earth’s global mean temperature variability originates in the tropics’) is that (eyeballing your first chart above) the March 2008 anomalies were down from their January 2007 peaks by about 0.3 C in the NH, 0.7 C in the SH and 1.05 C in the tropics.

Too soon to know that it is a true divergence. Might be a trend to colder winters combined with a general cooling trend. The sharp uptick suggests a regime change, which may render short term measurements of anomaly meaningless.

#6 yes, it means more because most heat come in at the tropics, and is a larger area than the poles, for the same latitude range.

Looking at the anomaly map, it looks like a large “heat wave” which runs from the far eastern end of Russia / North of China, running across Russia and then dipping down towards the Persian Gulf. See if I can link the anomaly map right:

http://www.remss.com/msu/msu_data_monthly.html?channel=tlt

Small question: does the SH here consists of the entire SH or the SH outside of the tropics? Or maybe I just want to know how NH, SH and tropics are defined. If there is overlap between the tropics and the NH/SH in these figures, would it be possible to put up a figure with NH outside of the tropics and SH outside of the tropics? Just being curious.

#9 The extents can be found on the link to RSS here http://landshape.org/enm/march-global-temperatures-2008/. For this figure I used the last 2 columns from 0 to x. It includes the tropics, yes.

#9 Spence, I don’t look at these maps regularly to be able to tell if this is significant. I would have thought a small variation across a large area would usually contribute to the mean more than a local phenomenon.

Regarding the Difference Between NH & SH, it appears to be driven by the AMO over the long term.

http://tinypic.com/fullsize.php?pic=23mn96c&s=3&capwidth=false

Perhaps the circulation cells interact with UHI just a tad more than conventional wisdom might suggest.

Cross-posted and linked at the globalwarmingclearinghouse.blogspot.com

#12 that looks to be a pretty extraordinary local phenomenon. The anomaly map certainly fits the anecdotal evidence for North America – we’re begging for our uptick.

My guess: Very few sunspots and also very little volcanic ash in atmosphere. Less heat from sun, but rays brilliant and unobstructed by ash. NH has the clean, clear sunlight, and temps jump, while the weakness of the same sunlight (due to sunspot cycle) is felt at equator and in SH.

Soot.

Black soot from the coal fires of Asia. Black soot from the diesel cars of Europe.
China is using dirty coal. Europe decided to meet Kyoto goals with diesel.

Black soot absorbs sunlight and heats up more than areas not covered by black soot.

http://www.terranature.org/globalWarmingSoot.htm

Are there any satellites that can measure albedo changes?

Hmm, not noticing that here. Of course all the sunlight is still being reflected by
the 12 feet of snow we still have on the ground :^))

Jim in Ottawa, Ontario, Canada

Jim, shut down the nuclear reactors, burn coal instead and replace half the cars in central canada with diesel powered ones.

The soot will help melt the snow.

#13 Bob, That’s a possibility. A post on AMO here http://www.climateaudit.org/?p=1261

Admin: Sorry, I don’t know your name.

I’ll match your AMO link. (RealClimate glossary that says the AMO contributes significantly to NH temperature anomaly.)

http://www.realclimate.org/index.php?p=38

And raise you one. (Knight et al paper that quantifies how much the AMO contributes to NH and Global temperature. Assuming the paper is right, it’s not as much as RealClimate claims. But since the AMO appears to have started down again, it’ll help lower NH and Global temperatures–and hopefully Arctic temps, too.)

http://holocene.meteo.psu.edu/shared/articles/KnightetalGRL05.pdf

Regards

Hi Bob, I’m David. I don’t have an opinion on this so thanks for the links. Knight claims only 0.1 – 0.2 K contribution from AMO between crest and trough. So its not really much, even as much as the LT deviation between the NH and SH above. The difference above is about 0.6K over 30 years, which is much more significant I would think.

I think RSS should really have close look at NH data. The rise is confined to Asia. I would not be surprised if “a correction” is issued shortly. We have to wait for UAH data which should closely match RSS if correct

#24 vg. Yes it is extraordinary. I would not be surprised if the NH is spuriously high.

Can anyone tell me why the global average for RSS MSU temperatures is weigthed toward NH? For March 08 (NH + SH +Tropical) / 3 is negative but global is positive…

Buck: You’ve got Tropical thrown into the average and it doesn’t belong there. You only need the two hemispheres.

Yet (“NH” @ 0.465 + “SH” @ -0.325)/2 does not equal “Global” @ 0.079 because the hemispheric and global references are misnomers. “NH” only covers from 0 to 82.5 latitude (not 0 to 90) and “SH” only covers 0 to -70 (not 0 to -90). Likewise their “Global” coverage is not 90 to -90 deg latitude, but 82.5 to -70.

Bob Tisdale– Do you have a link showing current AMOs? I found this:
figure

and this

data.

But the figure only gets to 2000 and the data only gets to 1990.

Bob… never mind. I found this:
AMO page.

I also clicked to this link, which is cool:
tool to make maps