The interpretation of the circulation of the Antarctic atmosphere that is provided below is different to that you will find in climate texts. The distribution of tracers of air of different composition reveals the circulation. There is a notion that the polar vortex constitutes a barrier to interaction, people speaking of a strong or a weak vortex……..all this is nonsense. Then there is the notion that ‘atmospheric waves’ disturb the vortex….well…. perhaps in fairyland.
Our interest in ozone is primarily driven by the fact that we are aware of the protective effect that it provides via the mopping up of ultraviolet light that is harmful to life at the surface of the planet.
There have been many scares related to ozone depletion in the last fifty years. There have been concerns about the effect of spray can propellants, refrigerants and supersonic jets on the upper atmosphere. The most celebrated concern relates to the Antarctic ‘ozone hole’, a natural feature of the Antarctic circulation in late winter that is said to be aggravated due to the influence of man. The hole was first noticed at Halley Bay in 1956 using Dobson’s spectrophotometer. It existed prior to the concern for the ozone environment. Today it is too often mistakenly suggested that ‘the hole’ is entirely the result of the activities of man. The Montreal Protocol was designed to end the manufacture of the substances held to be responsible for ozone depletion. These substances include Chlorofluorocarbons, Halons and Carbon Tetrachloride.
As documented in previous posts, ozone has a dominant but unrealised role as a natural greenhouse gas that accounts for the differences in density in the ‘weather-sphere’ that is in turn responsible for the synoptic situation that drives winds and weather across the globe. The weather-sphere manifests in mid to high latitudes. It includes the upper troposphere overlapping both troposphere and the tropopause where the temperature does not change with altitude. In mid to high latitudes the ‘weather sphere’ constitutes the middle of the atmospheric column centred on the 100 hPa pressure level. It does not include the troposphere below 600 hPa. Change in the ozone content in the weather-sphere drives change in climate. This natural source of climate variation manifests as marked variations in surface temperature associated with atmospheric processes. These processes are most marked in the winter hemisphere. The processes result in extreme variations in surface temperature in January and July that originate in the Arctic and the Antarctic respectively. There is a demonstrable relationship between ozone, surface pressure and the height of the tropopause. Knowledge of this relationship dates back to the first half of the 20th century, particularly in the works of GM Dobson and the French Meteorologist de Bort who explored the upper air with helium balloons at his own expense.
Realising the significance of ozone to the synoptic situation it is therefore a matter of interest to explore the mechanisms that account for the concentration and distribution of ozone in the atmosphere and in particular to elucidate such phenomena as:
- The increase in the ozone content of the air in the winter hemisphere.
- The historical trend to a warmer stratosphere in the southern hemisphere, involving a marked ramp up in temperature in the late 1970s with peak warming in October that has been maintained to this day.
- The maintenance of high ozone concentrations in polar atmospheres into spring in spite of the gradual shortening of the atmospheric path after mid winter.
- The intensification of cyclone activity off Antarctica through to September/October in conjunction with the appearance of the Antarctic Ozone Hole.
- The long term loss of atmospheric mass (reduction in surface pressure) in high southern latitudes between 50° of latitude and the Antarctic pole.
- The reasons for the generalized deficit in ozone in the southern by comparison with the northern hemisphere.
- The circulation of the atmosphere as it responds to and in turn influences the concentration of trace gases according to latitude and altitude.
- The role of the high latitude circulations in regulating the distribution of ozone and the substances that naturally deplete ozone including H20 and Nox that are abundant in the troposphere.
The Copernicus Atmospheric Monitoring Service via this site provides us with data showing the composition of the atmosphere over Antarctica:
Seasonal variations in the stratosphere are much more extreme than at the surface. Our examination of the Antarctic atmosphere is focussed on a single day, August 20th 2015 when the temperature of the stratosphere is advancing steeply from its winter minimum in the first week of August as is apparent in the diagram below.
Chapter 21 is required reading if the reader is to understand the movements in the air described in the current chapter. The reader must comprehend the nature of the ‘weather-sphere’, an entity that is neither troposphere nor stratosphere as conventionally defined.
In the next chapter we will move forward in time to chart the development of the Antarctic ozone hole.
AUGUST 20th 2015
In this analysis we depend upon pattern recognition. Both NOx (oxides of nitrogen) and H2O (water) destroy ozone. NOx is uplifted from the troposphere by convection in the tropics. The tracing applied by the author to the first diagram is duplicated as an overlay on the diagram below.
It is clearly evident that NOx is very much involved in the destruction of ozone in low latitudes accounting for the relatively high tropopause and extremely low temperature at 100 hPa over the equator. The activity of NOx under the influence of generalized convection in low latitudes helps us to understand why ozone partial pressure is greater near the poles. Another factor tending to promote the presence of ozone at higher latitudes is the increased length of the atmospheric path that absorbs some of the short wave energy responsible for the photolytic destruction of ozone and especially so in the night zone in winter.
The banded, ribbon like structure in ozone rich air at 100 hPa is a response to the west to east movement of the atmosphere driven by the high speed circulation of the air inside and outside the polar vortex that increases in velocity with elevation up to and beyond 10 hPa. Tracers of air from the polar circulation spiral outwards towards the equator as streamers caught in air that has an equator-wards component in its direction of movement. In understanding the atmosphere one must comprehend the forces that are at work at 100 hPa in mid to high latitudes. If there is an outstanding problem in climate science it is the failure to appreciate the forces involved in generating differences in air density and the fact that the energy supplied by the surface is relatively inconsequential in comparison with the forces at work in the vicinity of the tropopause.
Ninety nine percent of the atmosphere lies below the 10 hPa pressure level. The elevation at 10 hPa is just thirty kilometres. The surface circulation rotates in the same direction as the Earth at a faster rate than the rotation of the Earth itself. The atmosphere at 10 hPa super-rotates at an even faster speed. It appears that the atmosphere is an electromagnetic medium where the motive force contributing to the winter circulation increases with elevation, particularly over the pole. Recent research identifies a response of the zonal (east-west) wind in high latitudes to geomagnetic phenomena. As an electromagnetically responsive medium, the upper atmosphere is impacted by the solar wind because it changes the electric fields. The response to this change is via the distribution and the concentration of ozone and other trace gases. We know this because there is a change in the height of the ‘tropopause’ that is linked to geomagnetic activity. Accordingly, what is described here is ultimately linked to activity on the sun.
On the perimeter of the Antarctic continent intense upper air troughs are formed that propagate downwards towards the surface as an ascending circulation with the cellular structure of a polar cyclone. Meteorologists monitor the strong winds of the jet stream at 250 hPa but these are not the strongest winds in the polar circulation. In mid winter the strongest winds are to be found at the highest altitudes. Essentially the circulation responses to forces aloft rather than forces at the surface.
The 100 hPa pressure level is plainly, given the circulation of ozone in the air evident in the left hand diagram, a mixing zone where ozone rich air circulates in peripheral contact with ozone deficient air located over the continent. This mixing is material to the development of polar cyclones that drag up air from the near surface layers but even more so, attract mid latitude air towards the core in the horizontal plane where the more important differences in atmospheric density and wind strength manifest. The location of very cold dry air of mesospheric origin is indicated in the diagram above by a blue line that marks the perimeter of very cold, very dry air. The blue line is derived from the diagram at right below.
A striking feature of the circulation at 100 hPa is the heterogeneity in the composition of the air. This is a matter of immediate interest. How and why does this pattern manifest? What accounts for the ozone deficit between ribbons of air that exhibit an elevated ozone content when plainly, at high latitudes, at the 100 hPa elevation, there is no NOx present? The direct ascent of NOx from the surface is not evident at 100 hPa . Plainly the ozone is being drawn into and traversing a domain of very different air that has a much lighter ozone content and virtually no water content, devoid of NOx, indicating a process of lateral mixing where the ozone traversing the polar domain, perhaps due to a limited rate of intrusion, becomes a minor part of the composition of the air behind the vortex. Notice that at the 100 hPa level peak ozone concentration is 1.6 ppmv whereas it ramps up to 5 pppv at 50 hPa.
The vortex actually constitutes a chain of discrete low pressure cells that surround the continent. The essence of each independent cell is the ingress of parcels of air that are essentially very different in temperature and chemical composition. The vortex is not an exclusive but very much an inclusive, homogenising process that can never run to completion, even though it may more closely approach homogenization in summer. The vortex constitutes a very different set of phenomena to that described in conventional climate science texts.
The circulation at 100 hPa is indeed a classic spiral of the sort that manifests when pigment is mixed into a can of house paint, but in this case a mixing process that can never reach completion.
Source of diagram at left here.
In the top diagram we have wind and temperature at 250 hPa and superimposed on that, the distribution of Nox and ozone at 100 hPa. On the second diagram we have the distribution of H2O, and superimposed on that the distribution of both NOx and ozone.
It is plain that:
- The ozone content of the air at 100 hPa is closely associated with differences in air temperature and the flow of the circulation. We know that the ozone content of the air at 500 hPa through to 100 hPa and above is closely associated with the synoptic situation at the surface. Upper level troughs drive the circulation of the air in mid to high latitudes. Upper level troughs are associated with warm air heated by ozone. Troughs manifest in maps of geopotential height, upper air temperature and upper air ozone content as seen here. These are the essential aspects of the weather-sphere, an upper air rather than a near surface phenomenon.
- There is more water in the air at 100 hPa in near equatorial latitudes and very little over the Antarctic continent. The water in the tropics is in the same zone that exhibits elevated NOx. The uplift of moisture and NOx in low latitudes is patently an influential dynamic affecting the ozone content of the global atmosphere.
- The zone of very low temperature over Antarctica is associated with air that contains very little moisture, some ozone but no NOx. At its heart is a rotating, three pronged mass of very cold dry air shaped like a tyne in implement that could be towed behind a tractor to till the soil. This is primarily air that has descended from the mesosphere. Mesospheric air descends in winter under the influence of high surface pressure. The rate of descent of this air is a prime determinant of the ozone content of the global atmosphere, much more influential that fluctuations in the quantum of short wave solar radiation emanating from the sun.
- Ozone rich air that is warmer than tropical air lies between the warm, wet, Nox rich air of the tropics and the cold, very dry air descending from the mesosphere.
- In the mid latitudes appreciable quantities of moisture from the near surface atmosphere are associated at the 100 hPa level with warm, low density air containing ozone. H2o is conjointly an absorber, with ozone, of infrared radiation. In the weather-sphere it is variations in air density that determine the synoptic situation that is mapped at 500 hPa and at the surface. Water vapour and ozone are allies in determining the density of the upper air.
Lets now look at ozone and NOx at 100 hPa from an equatorial perspective.
In the global (rather than the polar stereographic) view, we see that the zones of elevated NOx content at 100 hPa are associated with zones of low ozone concentration in low and mid altitudes. In August ascending NOx from the troposphere affects ozone concentration from 50-60° North latitude to about 40° south latitude. Plainly NOx tends to reduce ozone concentration more in the summer than the winter hemisphere. Because of the distribution of land and sea the annual range in temperature (and convection) is much greater in the northern than the southern hemisphere.
There is a staccato wave like pattern of enhanced NOx/depleted ozone exhibiting a north south orientation across the near equatorial latitudes. These features may be causally associated with the ‘equatorial Kelvin waves’ observed by meteorologists.
Plainly the greatest impact of NOx on ozone at 100 hPa is seen in the northern hemisphere. However, trace amounts of NOx have a relatively severe depletion effect on the ozone content of the southern lower stratosphere that is apparent in the wing like extensions south of latitude 30° south.
Despite the enhanced attack of NOx in the northern hemisphere ozone levels are always higher than in the southern hemisphere indicating that the more influential driver of change in hemispheric ozone is by far the intake of air from the mesosphere at the respective poles.
Lets transfer our attention to ozone and NOx at the 50 hPa level.
Note that the ozone profile traced in the higher diagram is overlaid on the lower diagram. The zone of elevation of the air associated with polar cyclones is centred on latitude 60-70° south that is poleward of the annular ring of higher ozone values at 40-70° of latitude on the margins of the Antarctic continent In fact it lies between ozone rich air to the north and ozone deficient air over the continent. This is the mixing zone. We might call it the Polar Front. Its a meeting place where things get stirred together. It exhibits the lowest surface pressure seen anywhere on the planet and it manifests as chain of polar cyclones.
The pattern of surface pressure across the globe in August is documented below, courtesy of the JRA 55 atlas to be found here. If we compare the pattern of surface pressure with the distribution of NOx the two are identical. At 50 hPa NOx is plainly a marker for uplift. That uplift involves a lateral intake of NOx rich air between the 100 hPa level where NOx is not evident and the 50 hPa level where NOx is evident. Lateral movement of the air is a very strong feature of the polar circulation surrounding the Antarctic continent. NOx and ozone are entrained at this level, one acting to some extent as a marker for the other. Note the ribbon of ozone deficient air that lies between the band of ozone rich air and the margins of the continent. It is not the edge of the landmass that governs the location of the circulation even though it may appear to do so. A mass of sea ice surrounds the continent in August. Rather, it is the surface pressure arrangement with a planetary high in surface pressure over the continent itself and a planetary low at 50-60° south latitude. This is the undiscovered gorilla in the climate science chamber of conceptual errors.
Referring now to the diagrams immediately above: The core of air with depleted NOx marked ‘mesosphere’ is surrounded by NOx rich air at 50 hPa. Air that contains NOx is drawn in laterally to participate in the high latitude circulation via intense polar cyclones that elevate air into the stratosphere. These cyclones do not respect a hypothetical ‘tropopause’. These cyclones are more intense in terms of geopotential height contours (or isobars) at 100 hPa than at the surface. It is at this level that the energy to drive the circulation is to be found. The circulation is powered by long wave radiation from the Earth whether the sun is below the horizon or above the horizon. The rotation and the uplift is a function of differences in the ozone content of the air…….unknown to climate science.
In the core of the Antarctic circulation there is a zone of mesospheric air that is devoid of NOx. At left we see that the ozone content of this core of mesospheric air is similar to the air in near tropical latitudes. We do not expect air from the mesosphere to contain much ozone. It is present as a direct result of the intake of ozone rich air that spirals inward towards the heart of the circulation situated more or less over the geographic/ magnetic pole. This process adds ozone to the parcel of mesospheric air that lies within the core disguising its real character. Mesospheric air dilutes the ozone content of the global stratosphere.
Note that tracers of ozone outside the zone of heaviest concentration at 50 hPa are associated with tracers of NOx. This represents air spun out from the vortex circulation towards mid and low latitudes. The source of these tracers is seen in the structures at 5 to 6 O’Clock and another at 2 to 3 O’Clock. There is plainly a process of vigorous horizontal mixing at 50 hpa that gives rise to these streamers of air rich in both ozone, NOx and H2O. The latter must be ultimately derived from the lower, near surface atmosphere, perhaps elevated by polar cyclones that travel equator wards into the mid latitudes. Unless we comprehend a ‘weather-sphere’ that is driven by ozone heating and in doing so discard our notions of an ‘ozone free troposphere’ extremes in lateral movement in the middle atmosphere can not be comprehended. Only when we allow for differential heating of the air according to its ozone and water content can we account for the differences in density that give rise to these powerful upper air movements.
The observation that total column ozone maps surface pressure in the mid latitudes inevitably leads to a very different idea as to what constitutes the ‘weather-sphere’. It leads to the conclusion that it is ozone in high latitudes that drives the global circulation rather than solar energy acquired in tropical latitudes. Effectively, we tip UNIPCC climate science on its head and give it a damn good shake. It’s wholly and abundantly necessary.
We see above a comparison between wind at 70hPa, surface atmospheric pressure, the ozone content of the air and the H2O content of the air, the latter at 50hpa.
There is a marked deficit in H2O inside the margins of the Antarctic continent associated with air of mesospheric origin. The wettest air, if air containing 5.5 ppm by volume can be described as wet, lies partly within and across the inside margin of the ozone rich zone at 50 hPa. Above, we see that this air is NOx rich. This zone exhibits extremely low surface atmospheric pressure. Relatively warm air from the surface westerly flow is drawn in and elevated with ozone rich air that is also wet, the two ‘greenhouse gases’ warming by absorbing radiation from the Earth itself.
Above we see that the distribution of NOx and H2O is co-extensive lying between the very cold dry air from the mesosphere and the band of ozone rich air charted in the earlier diagrams.
We are now in a position to describe the nature of the air in the ascending columns within polar cyclones. That air at near surface elevations derives from the westerly stream being relatively rich in both NOx and H2O and the polar easterly stream of near surface air off the continent. Above the 500 hPa pressure level the circulation is invigorated and its composition changes. Ozone rich air is anomalously warm. Uplift is generated aloft where warm, ozone rich air is reinforced with air containing water both constituting potent absorbers of long wave radiation from the Earth.
STRUCTURE OF THE ASCENDING AND DESCENDING CIRCULATIONS
Above left we see a representation of peak ozone content of the air at 50 hPa as a tracing over the map showing the composition of the air at 10 hPa. The map at right shows Total Column Ozone. It is apparent that there is a widening of the annular ring of high ozone values with increasing elevation. This cone shaped space over Antarctica is occupied by mesospheric air in winter and spring under a regime of high surface pressure over Antarctica. In fact surface pressure over the continent regularly attains a planetary peak at about 1050 hPa.
There is no parallel to this structure in the northern hemisphere. If there were the evolution of the climate of the Earth would be very different.
Below we see the temperature of the air and its circulation in the clockwise west to east fashion about the globe with the view centred over Antarctica.
Between 70 hPa (17 km) and 30 hPa (30 km) the air ascends as it circulates and it warms due to the fact that it is the warmer, less dense air that preferentially ascends. The tracing representing total column ozone in pink is roughly co-extensive with the warm zone.This is the reason why the stratosphere at 10 hPa is warmer near the winter pole than it is over the equator. It is the accumulation of ozone at elevation and its ability to derive energy from infra-red radiation from the Earth itself (in the relative absence of short wave radiation from the sun) that produces the warm zone centred on about 35° south latitude at 10 hPa. Here is another error in UNIPCC climate science. The stratosphere at and below 10 hPa owes its warmth to long wave radiation from the Earth, not short wave radiation from the sun.
Within the column of colder air that descends in the core of the circulation, the air at 50 hPa is 12°C cooler at 70 hPa than it is at 10 hPa. This testifies to the importance of lateral movement in the stratosphere that allows cold air to enter the circulation other than via vertical descent.
The core of the circulation is relatively ozone deficient. However, the ozone content of the core does not represent the ozone content of mesospheric air because it is a function of mixing processes at all levels. Ozone is introduced from the perimeter.
So far as NOx is concerned, the evidence is that it enters the descending core primarily via ascent from the lower atmosphere rather than descent from the mesosphere although the latter can not be ruled out as an influence on the composition of the air that enters the circulation from the mesosphere. The descent is slow and there is time for reactions to occur.
The evidence suggests that the most vigorous mixing across the air streams occurs between about 300 hPa and 50 hPa.
The lapse rate of temperature in the Antarctic atmosphere below 100 hPa is much less than in the mid and low latitudes reflecting a significant ozone presence down to the near surface layers. As surface pressure increases so does the rate of descent bringing warmth to the surface that is always colder than the atmosphere.
Mixing is evident in the streamers of air that radiate from the core between 100 hPa and 50 hPa. Mixing involves the escape of cold air of mesospheric origin into the wider atmosphere imposing an ozone control dynamic with rate of flow of mesospheric air a function of surface pressure and geomagnetic influences. In this way, the polar atmosphere is set up for solar control of the synoptic situation globally.
In the next post I will explore the manner in which NOx from the lower atmosphere floods the lower stratosphere to produce an ‘ozone hole’ in the lower stratosphere as the temperature of the stratosphere rapidly increases in spring cutting off the flow of cold air from the mesosphere, dramatically reducing the rotation speed of the polar circulation and by late December temporarily reversing its flow. It then circulates in an anticlockwise direction at 10 hPa while maintaining its clockwise circulation at and below 70 hPa despite the flooding of the polar cap with slowly moving warm, relatively ozone rich air and the almost complete disappearance of cold mesospheric air. Nevertheless, it appears that strong lateral flows in the region of 250 hPa to 100 hPa continue to supply very cold dense air that rotates in an anticlockwise fashion in localized high pressure circulations over the Antarctic continent as a less frequent adjunct to a zone that continues to be characterised by dramatically low surface pressure, a product of polar cyclone activity.
Understanding the polar circulation is necessary if we wish to understand the origins of natural climate change and with it the true origins of the modern warming. If that is possible, much time, trouble, waste and distraction can be avoided. Humanity can then get on with the business of supporting itself, pursuing the process of technological change and performing work with machines that will raise living standards without the worry that it is storing up trouble for the future.