RESOLVING BASIC GLOBAL WARMING MODELLING ISSUES

There has been a long ongoing discussion about the apparently different temperature responses of the surface and the troposphere over the past two decades. On the one hand we have a group besotted by the predictions of the climate models who would be more comfortable if the satellite data (and their supporting balloon data) could be demonstrated to be erroneous. There has been quite an effort to identify flaws in the satellite analysis methodology and reconcile the tropospheric temperature trend to that of the surface observations and the model simulations. On the other hand we have a group who accept the satellite data and argue that the computer models are therefore wrong. But this latter group have not put forward a satisfactory argument as to why the satellite trends of the tropospheric temperature are logically plausible nor the defect of the computer models.

Let me point to why the computer models might be wrong in their predictions of tropospheric warming in the tropics. It relates to the common parameterizations of cumulus convection. If we go back to the original formulations of cumulus parameterization in NWP models the formulations were essentially an adjustment to maintain computational stability - physics was not a primary consideration for short term forecasts with limited computing power. When the atmosphere became saturated the lapse rate was adjusted to the pseudo-adiabatic lapse rate in an energy conserving manner. It was rationalised that the adjustment was like what convection did in the atmosphere - convective adjustment. Unfortunately the sudden adjustments meant that there were sudden shocks to the computational system that had to be smoothed with a mathematical operator that was likened to friction. To eliminate the sudden shocks more elaborate parameterization schemes have been formulated that are also essential for long period simulations.

In the equatorial regions there is ongoing convergence of moisture by the large scale flow; the dynamics of the large scale atmospheric circulation also tend to make the equatorial atmosphere convectively (and computationally) unstable (potential temperature increases with height and so forced ascent tends to cool the middle and upper troposphere). The convective parameterisations subsequently developed ensure that latent heat accumulating through the convergence of moisture in the lower troposphere is available to offset the dynamical cooling of the middle and upper troposphere. Note that the convective parameterisation must ensure that a stable temperature lapse rate is maintained, otherwise the computer model will suffer computational instability.

I would be interested in the views of people more familiar with the convective parameterizations but it would seem to me that enhancing the convergence of moisture would naturally lead to a further warming and stabilising of the troposphere. That is, the middle and upper troposphere would warm with time.

In 1958 Riehl and Malkus (published in Geophysica) proposed a convection process quite different to the convection parameterizations later developed for computer models. Their deep convection requires a lapse rate of the troposphere which is less than the psuedoadiabatic lapse rate to ensure buoyant ascent in the 'hot towers'. In this model, if the middle and high troposphere warmed relative to the surface then convection would cease.

Implicitly the tropospheric temperature and lapse rate are constrained by the upper limit of the temperature profile of saturated buoyant ascent from the boundary layer. Convection is regulated by the rate of radiative cooling of the tropical troposphere and the export of energy by Rossby Waves to meet the need of the net radiation deficit of middle and high latitudes (terrestrial radiation to space exceeding solar input).

The other aspect of the Riehl and Malkus model that needs to be considered is that deep tropical convection only takes place over the boundary layer air of those regions of the tropics with the highest energy. This is because the baratropic troposphere has little spatial temperature gradient, particularly as compared to the surface temperature gradients. As a consequence, it is not the average sea surface temperature of the tropics that determines the temperature of the tropical troposphere but the warmest sea surface temperatures. I would be interested in the views of others, but to my reckoning the TAO buoys of the western Pacific Ocean (the warm pool) do not show any trend since observations commenced and have been steadily at about 30C. As this is the source of the highest energy boundary layer air in the tropics it is not surprising that the buoyant updraft temperatures, and hence the tropical troposphere temperatures, have also not increased. There is however observational evidence that these SST did increase in the middle 1970s - the Pacific SST shift that is referenced by IPCC TAR without explanation. Although satellite data were not available during this climate shift the balloon data do point to tropospheric warming during this period. That is, as the warm pool SST warmed so to did the temperature of the troposphere.

The movie, The Day After Tomorrow, depicted cold air in the high troposphere being drawn down to the surface causing the onset of the big freeze. Because potential temperature increases with height this scenario is impossible. The high troposphere air would arrive at the surface at about plus 50C under such a scenario, not its original temperature of minus 50C as depicted in the movie. Similarly the convective parameterizations in computer models attempt to redistribute boundary layer air through the troposphere against the potential temperature gradient. Very curious.

We should also note that the CMIP2 model intercomparisons (Covey et al - Lawrence National Livermore Laboratory) identified that on average the mass streamfunction associated with the Hadley Cell circulations in the models was some 25 percent less than is estimated for the atmosphere. This is a major model deficiency linked also to the convective parameterization.

William Kininmonth

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Climate skeptics following the debate about solar forcing of climate change may be interested in the news report from UC-Berkeley last month on a recently completed survey of supposedly sun-like stars displaying minimal activity.

From 1645 to 1714, there was very little sunspot activity over a 70-year period. This "Maunder minimum" coincides with the coldest part of the Little Ice Age in Europe and North America.

These quotes from Professor Geoffrey Marcy, and his graduate student, Jason Wright, highlight their conclusions:

Jason Wright: "Star surveys typically find that 10 to 15 percent of all sun-like stars are in an inactive state like the Maunder minimum, which would indicate that the sun spends about 10 percent of its time in this state."

Jason Wright: ". . . our study shows that the vast majority of stars identified as Maunder minimum stars are well above the main sequence, which means they're not sun-like at all, but are either evolved stars or stars rich in metals like iron and nickel."

Geoffrey Marcy: "What astronomers have assumed is that sun-like stars going through a stellar funk are actually very, very old stars whose magnetic fields have turned off forever. They are not in a temporary Maunder Minimum, but a permanent one. They're dead."

Geoffrey Marcy: "The fact is, we still don't understand what's going on in our sun, how magnetic fields generate the 11-year solar cycle, or what caused the magnetic Maunder minimum. In particular, we don't know how often a sun-like star falls into a Maunder minimum, or when the next minimum will occur. It could be tomorrow."

The complete news report from UC-Berkeley on nearby sun-like stars that mimic the Sun's "Maunder Minimum" is available at:

http://www.berkeley.edu/news/media/releases/2004/06/01_maunder.shtml

Is it possible that the (iron and nickel)/(hydrogen) ratio in the photosphere is decreasing during the present period of high solar activity and increased during the Maunder minimum as expected if "Deep-seated solar magnetic fields accelerate H+ ions upward, maintaining mass separation at the solar surface"? {See p. 197 of "Superfluidity in the Solar Interior: Implications for Solar Eruptions and Climate", J. Fusion Energy 21 (2002) 193-198}.

Oliver Manuel
http://www.umr.edu/~om
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NZCLIMATE TRUTH 54
JULY 29TH 2004

Proof Positive

The fundamental argument for the existence of global warming by greenhouse
gases is that these gases absorb infra red radiation from the earth, giving
a temperature rise in the atmosphere greater than that at the surface.

For some time now it has been evident that the claimed mean surface
temperature rise is greater than that in the lower atmosphere. If this is
really true the greenhouse theory must be wrong.

As the years go by the problem gets worse. The atmosphere measurements go
back to 1960 and all attempts to show they are false have failed. There is
simply no temperature rise up there.

Enthusiasts for the greenhouse effect have tried all sorts of arguments to
explain or cover up this basic difficulty of their theory. They try to argue
that there is a "lapse rate" reversal, for example. Scientific papers
attacking the theory have been routinely "peer-reviewed" out of the
"respectable" scientific journals and relegated to dissident websites or
"less respectable" journals.

These tactics now appear to have failed with the appearance of peer reviewed
papers in the top journals which show that the enhanced greenhouse effect
theory is simply false. The latest of these are the following.

Douglass, David H., Benjamin D. Pearson, S. Fred Singer, Paul C.
Knappenberger, and Patrick J. Michaels, 2004. Disparity of tropospheric and
surface temperature trends: New evidence. Geophys. Res. Lett., 31, L13207,
doi:10.1029/2004GL020212, July 9, 2004

Abstract

Observations suggest that the earth's surface has been warming relative to
the troposphere for the last 25 years; this is not only difficult to explain
but also contrary to the results of climate models. We provide new evidence
that the disparity is real. Introducing an additional data set, R2 2-meter
temperatures, a diagnostic variable related to tropospheric temperature
profiles, we find trends derived from it to be in close agreement with
satellite measurements of tropospheric temperature. This suggests that the
disparity likely is a result of near-surface processes. We find that the
disparity does not occur uniformly across the globe, but is primarily
confined to tropical regions which are primarily oceanic. Since the ocean
measurements are sea surface temperatures, we suggest that the disparity is
probably associated with processes at the ocean-atmosphere interface. Our
study thus makes unlikely some of the explanations advanced to account for
the disparity; it also demonstrates the importance of distinguishing between
land, sea and air measurements.

and

Douglass, David H., Benjamin D. Pearson, and S. Fred Singer, 2004. Altitude
dependence of atmospheric temperature trends: Climate models versus
observation, Geophys. Res. Lett., 31, L13208, doi:10.1029/2004GL020103, July
9, 2004

Abstract

As a consequence of greenhouse forcing, all state-of-the-art general
circulation models predict a positive temperature trend that is greater for
the troposphere than the surface. This predicted positive trend increases in
value with altitude until it reaches a maximum ratio with respect to the
surface of as much as 1.5 to 2.0 at about 200-400 hPa. However, the
temperature trends from several independent observational data sets show
decreasing as well as mostly negative values. This disparity indicates that
the three models examined here fail to account for the effects of greenhouse
forcings.

Geophysical Research Letters is the organ of the American Geophysics Union
and it has published a large proportion of the papers on climate change
reviewed by the IPCC.

Amongst the authors of the above papers are the prominent challengers of
greenhouse theory Patrick Michaels and Fred Singer. The papers merely
assert, and show conclusively, that all climate models based on the enhanced
greenhouse effect undoubtedly predict a higher temperature rise in the lower
atmosphere than would be observed on the earth's surface. Also, the rise in
the lower atmosphere is negligible for the past 40 years.

Usually papers such as this attract attempts to answer or make excuses for
them in the popular press, This time there is silence, followed by arrogant
assertions, such as those from Dr David King, Chief Scientific Advisor to
the British Government, that global warming is "certain" and that the
"scientific community" is united in this view.
How long can they tough it out?


Vincent Gray
Email: vinmary.gray@paradise.net.nz
"It's not the things you don't know that fool you.
It's the things you do know that ain't so"
Josh Billings

These Authors would be pleased to get comments on these assessments.