The presumption that ‘the science is settled’ is incorrect.
This post aims to give readers an understanding of the dynamics of the coupled circulation of the stratosphere and the troposphere at the poles that drives surface pressure, the temperature of the troposphere, cloud cover and surface temperature. It recently appeared at Watts Up With That. Here, in the interests of clarity, it appears in slightly expanded form.
Shifts in the atmosphere to and from Antarctica occur on daily and weekly time scales. Witness the change between the decade starting 1948 and the decade starting 2001 shown in figure 1.
Figure 1 Change in sea level pressure according to latitude mb.
The shift in the atmosphere over Antarctica that took place between 1948 and 2007 occurs in winter, spring and summer with greatest effect on temperature at 10hPa at 80-90°south latitude in August and September. Why is the effect on temperature greatest at the highest elevation? It is due to the influence of the night jet on stratospheric ozone levels via the introduction of NOx from the mesosphere. Night jet activity varies with surface pressure.
The effect on the polar atmosphere of greater ozone levels is to invigorate the coupled circulation of the stratosphere/troposphere lowering surface pressure at 60-70°south and invigorating the westerlies.
The influx of ozone into the troposphere results in warming, reduced relative humidity and cloud. The cloud effect is carried equator-wards in a north westerly direction by the counter westerlies resulting in the characteristic V shape in sea surface temperature anomalies.
A long term decline in surface pressure in Antarctica is consistent with strong warming in the southern Hemisphere of the sort experienced between 1948 and 1978.
A fall in pressure in Antarctica enables/produces a rise in pressure in the Arctic that results in cooling. So, the southern hemisphere warms as it did between 1948 and 1978 while the northern hemisphere cools. After 1978 the habitable latitudes in the north warmed while temperature in the south remained static. See the Character of Climate Change parts 1 and 2.
Figure 2 Temperature by month at 10hPa and 80-90° south. °C
Figure 3 below shows that the temperature increase was highest at the highest altitude. Temperature peaked in 1978 and has fallen away since that time. The southern hemisphere has not warmed since 1978, a fact well documented in my post The Character of Climate Change parts 1 and 2. In UNIPCC ‘Climate Science’ the fact and the implication of these changes in the southern polar stratosphere are unrecognized.
Warming in one hemisphere while the other cools is inconsistent with the greenhouse thesis. After 1978 the northern hemisphere warmed while temperature in the more habitable latitudes of the southern hemisphere did not change.
Figure 3 Evolution of temperature in the stratosphere at 80-90°south. Twelve month moving average. °C.
Gauging pressure change at the poles
The change in atmospheric pressure at the poles can be monitored as the Arctic Oscillation Index (AO) or the Antarctic Oscillation Index (AAO) as depicted in figure 4 and 5. Although these indices are computed as a ratio of atmospheric pressure between the poles and the high mid latitudes, most of the change in pressure occurs at the highest latitudes.
The right axis in figures 4 and 5 is inverted. The Arctic Oscillation Index and the Antarctic Oscillation index vary inversely with polar pressure.
Figure 5 Sea level pressure at 80-80°south and the AAO. Left axis SLP mb.
Knowing the relationship between the AO and the AAO and polar pressure is important because these indices are computed daily. The change in polar pressure is fast and if one wishes to see the dynamics in action and speculate as to the physics involved you need data at this frequency.
Dynamics in the The Polar and Equatorial atmosphere as pressure rises and falls at the poles
The dynamics of how the high latitude atmosphere behaves is the same at both poles.It is convenient at this point to consider the Arctic.
Daily data for both the AO and the AAO can be found at:
In figure 6 we can see that a fall in the AO (increased surface pressure) is always associated with a strong increase in the temperature of the atmosphere below 100hPa. The warming extends all the way to the surface. As air descends, the net of ozone molecules gathering long wave radiation becomes finer. This is classic greenhouse activity but in this case we see a potent greenhouse gas from the stratosphere entering the troposphere producing localized heating of the air. The warming seems to diminish below 500hPa, perhaps because the surface at the poles is always cooler than the air above it.
The latitudinal coverage of figure 6 extends between 65° and 90°north. So figure 6 does not encompass the zone where the troposphere is particularly affected by the descent of ozone (latitude 50-60°north). This is responsible for the zone of ‘negative velocity’ (ascending air) in figures 8, 9 and 10 that are colored mauve through to blue. A zone of descending air colored red is located between 70 and 90° of latitude. This pattern is in conformity with the dynamic described in the last paragraph in relation to figure 6 where a low AO index (high polar pressure) is associated with warming of the air column below 100hPa as the atmospheric column descends.
Zones of descending stratospheric air at 60-70° south, while they are better spread and more continuous than in the northern hemisphere (at 50-60°north latitude) are nevertheless discontinuous. Figure 7 shows that the recent cooling of the stratosphere at 60-70° south and 10hPa is most evident between the Greenwich meridian and 180° east.
Source of figures 8,9 and10: http://ds.data.jma.go.jp/gmd/jra/atlas/eng/atlas-tope.htm
Inspection of these figures reveals that November is the transition month when coupled circulation is enhanced in the Arctic and loses strength in the Antarctic. In the Antarctic, the lowering of the cold point from its winter altitude of about 25hPa diminishes the coupling of the stratosphere and troposphere via its effect on the strength of convection.
Comparing high with low latitude dynamics in a warming episode at the poles
From figure 11 below we discover that:
1. When the Arctic (or Antarctic) upper stratosphere warms the equatorial upper stratosphere cools. This should be expected given the thickening of the atmosphere at the equator and a slight outward movement of the zone of heaviest ionization. That we see this activity suggests a significant plasma presence in the equatorial middle and upper stratosphere.
2. Relating the timing of warming events shown in figure 11 to the date of their occurrence in figure 6 we see that, as the upper stratosphere warms at the pole, the AO index increases, confirming a loss of surface pressure at the pole. This warming of the polar atmosphere, greater with altitude is consistent with a reduced flow of NOx from the mesosphere via a weakened night jet.
3. Going back to figure 6 we observe a cooling of the air in the lower profile as the polar upper stratosphere warms suggesting a commencement of a general uplift of the entire polar air mass. This is consistent with an increased flux of ozone into the troposphere on the margins of the night zone, a lowering of surface pressure there, cloud loss and increased surface temperature. This is the warming dynamic. Call it ‘Global Warming’ if you like but please recognize that it is reversible.
How much of this coupling of the stratosphere and the troposphere is maintained over summer when the cold point in the stratosphere descends? To assess this we can simply look at the pattern of geopotential height anomalies at 200hpa (upper troposphere) that are a product of the descent of ozone. We must bear in mind that no month or season can be ‘typical’ and the concept of an ‘average flow’ is inappropriate at anything less than the time scale required for the complete evolution of the phenomenon. Our records are not long enough to support such an analysis. However, flux in wind strength in the southern high latitudes, a direct consequence of pressure change at 60-70° south latitude, suggest an evolution over a period of at least 120 years.
Lastly, in figures 11 and 12 we can observe that zones of anomalous warmth in the stratosphere are of opposite sign in the upper troposphere. In the coupled circulation it is the coolest parts of the stratosphere that descend into the troposphere. That makes a lot of sense.
Note: The dynamic described here is arguably ‘the’ climate change dynamic that accounts for the ‘Global Warming’ over recent time. We note in passing that it is never global and is wholly inconsistent with greenhouse theory. Warming can become cooling. Atmospheric mass will slowly return to Antarctica and as it does so the temperature of the southern stratosphere will continue to decline. Pressure will rise at 60-70° south and the westerlies and the trades will blow less strongly. Cloud will return and the surface will cool. The increase in polar pressure in the Arctic that began in the mid 1990’s will refresh the night jet and the polar easterlies producing a cooler stratosphere and much colder winters.
I have suggested elsewhere that there is nothing internal to the climate system that could drive this dynamic over a 120 year time schedule. Change in pressure is likely related to electromagnetic influences that are amplified by the coupled circulation. A fall in surface pressure begets a further fall in surface pressure due to the effect of pressure change on the night jet.
If this dynamic is acknowledged climate science as we know it today would be turned on its head.