http://www.realclimate.org/index.php/archives/2009/10/an-open-letter-to-steve-levitt/

It all made sense up until the comparision between the waste heat from solar cells and the 4 watts per meter of heat until a doubling of CO2 – which seems like an apples to oranges comparision to me.

He included a pdf of Jone et al 1986a, Northern Hemisphere Surface Air Temperature Variations: 1851-1984 and pointed me to Figure 5.
The caption for that figure mentions 13 point Gaussian filter “designed to suppress variations on timescales less than 10 years.” and “six extra years are used at each end with values equal to the mean of the six years at the beginning/end of each curve”.

This clarified his short e-mail in which he told me that “Most plots are either 10-year or 20-year Gaussian filters.”

Although I haven’t figured out the specific “20 year Gaussian filter” used, just doing 3 iterations of the IPCC 13 point Gaussian filter (about 20 year half amplitude by my calculation) does an emulation of the smoothed datapoints of the CRU data close enough for my purposes — which is to check what is being posted by JPL NASA at their Key Climate Indicators website intended for the general public.

The discussion on that page is yet another example of confirmation bias at work. Apparently the CRU would update the historical graph in March, just using Jan/Feb of that year as the annual average anomaly. That was OK in 2007 when it made the graph rise rapidly, but in 2008 that made the smooth temperature fall and that triggered a review of procedures.

This may explains the strange graph at climate.nasa.gov — the initial graph from CRU in March 2008 showed a strong downturn. Then they discovered the error. Perhaps NASA took care of the error by just flatlining the smoothed curve for the last few years and hasn’t gotten around to doing a 2009 update.

There is another web page
http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/
that does explain how the smoothing is done – 21-point binomial filter plus repeating the final year beyond the endpoint. But the smoothed graph there looks DIFFERENT from the graph on the page you refer to, so clearly a different method is used there.

CRU’s webpage has time series of annual global temperatures, with a smoothed plot. http://www.cru.uea.ac.uk/cru/info/warming/ . There is also a datadownload, complete with smoothed data through 2008.

This graph shows up in many places.
Does anybody know what the smoothing algorithm is, and how the end points are handled?

My interest arose from noting that JPL NASA is showing a perfectly flat line for smoothed temp over the last 3 years at
http://www.cru.uea.ac.uk/cru/info/warming/ even though the rest of the graph appears to be identical to the CRU annual+smoothed global temp plot.

The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values

Note that it’s before allowing for increased radiation due to warming.

Thank you for your reply. I really appreciate that.
But I do have still difficulties with this explanation, since net radiative forcing is the difference between incoming energy by radiation and outgoing energy by radiation. This difference integrated over time should be equal to the change in the energy content of the earth system.

This energy content change is mentioned in the IPCC AR4. The figure caption reads:
“Figure TS.15. Energy content changes in different components
of the Earth system for two periods (1961–2003 and 1993–2003).
Blue bars are for 1961 to 2003; burgundy bars are for 1993 to
2003. Positive energy content change means an increase in
stored energy (i.e., heat content in oceans, latent heat from
reduced ice or sea ice volumes, heat content in the continents
excluding latent heat from permafrost changes, and latent and
sensible heat and potential and kinetic energy in the atmosphere).
All error estimates are 90% confi dence intervals. No estimate of
confi dence is available for the continental heat gain. Some of
the results have been scaled from published results for the two
respective periods. {Figure 5.4}”

If the figure represents something similar to the energy content change of the whole system, for my opinion net radiative forcing should by energy content change otherwise energy conservation is violated, since CO2 can only hold back incoming energy.
In order to calculate the energy content change one needs to consider the different systems with heat capacities attached. A surface without a heat capacity attached seems to me for my gut feeling like a virtual energy constant that is added or subtracted on both sides of the equation, fairly arbitrary. One increases the net radiative forcing and balances it with IR radiation in the future from a thin surface layer that will occasionally heat to the temperature Ts. However the difference of 1.6 W/m2 needs to be in the system right now.
Energy content and conservation of energy is the physical reality, or not. Conservation of IR radiation is not a physical law. Of course the radiative properties are calculated by models, but how does one show that they are correct., if not with real quantities.
Best regards
Guenter