32 THE CLIMATE ENGINE THAT IS THE OZONOSPHERE

The ozonosphere could be regarded as stretching from the mesopause on the lower margins of the ionosphere to the surface of the globe. Within the ozonosphere the partial pressure of ozone is conditioned by numerous processes including  diffusion downwards from the ionosphere, transport from areas of local production, destruction by ionisation and via chemical means and just plain mixing of ozone rich with ozone poor air.

Beyond the equatorial latitudes, at lower altitudes and at low sun angles ozone is safe from the pressure of ionisation. EUV is used up in the ionosphere above the mesopause. The ionisation of oxygen demands wave lengths shorter than 240 nm. Ozone, being a large molecule is ionised by UVB. The longer the atmospheric path, the less there will be of these destructive wavelengths because they are used up in the process. Recent work suggests that the complement of ozone in high latitudes is increased via cosmic ray activity. The safest zone for ozone is the winter hemisphere where the atmospheric path is long. Where the atmosphere is in the shadow of the Earth ionisation of ozone is not possible.

UV spectrumOn that basis we would expect that ozone partial pressure should increase all the way to the surface of the planet. In practice, erosion from below by NOx prevents the increase in ozone partial pressure at lower elevations. This erosive process gives rise to a higher tropopause in the tropics where atmospheric uplift is most vigorous.Both chemical destruction and transport processes are instrumental in  elevating the tropopause in low latitudes.

The polar vortex is another zone of ozone erosion and in this instance from above. This  could be the most important source of change in the system. Inside the vortex  a variable amount of ozone deficient air is introduced in winter. The feed rate depends upon surface pressure. As surface pressure declines so does the velocity of the zonal wind in high latitudes and the penetration of this mesospheric air.

This chapter looks specifically at aspects of vortex rotation and the mixing processes that are involved in determining ozone partial pressure in the wider ozonosphere.

PROCESSES WITHIN THE ANTARCTIC POLAR VORTEX

At 1 hPa  the rotation of the atmosphere is west to east in the same direction as the Earth itself but at a faster rate. Zones of high ozone partial pressure (low surface pressure) form over the warmer waters in the lee of the continents and in particular in the western Pacific Ocean and to the south of Australia. These are zones of enhanced convection where ozone accumulates at the highest elevation. The data below is reported here:

1hPa global

Looking now from the polar perspective we can observe the ingress of ozone rich air into the vortex structure (circled) and using snapshots at six hourly intervals we can see the rate of rotation inside the vortex. Observe the structure that looks like a plant sprouting from soil.  Follow the black circle to observe the rotation rate as this structure is carried about within the vortex.

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Some features of the circulation worthy of note:

  • The vortex at 1 hPa is not uni-cellar in structure but exhibits multiple cells of descent that drag in ozone rich air from the ozone rich periphery.
  • The ‘periphery’ at 1 hPa represents an ‘annular’ or ring like structure, albeit quite asymmetrical in its ozone content.
  • The diagrams span the time between zero hour on the 13th June to 6 am 15th June with plots at six hourly intervals.It takes 2.5 days for one full rotation to occur within the vortex.
  • The zone of high ozone partial pressure outside the vortex does not rotate about the pole in 2.5 days. It is sticky, hanging in the East Indian- West Pacific sector. Here, ozone partial pressure is maintained in spite of the influence of erosive activity emanating from the lower mesosphere and perhaps some ionising radiation impacting from above (but likely very little). This node of enhanced ozone is fed from lower levels per agency of low pressure anticyclones that form near the tropopause, propagate to the surface and lift ozone rich air to the top of the atmosphere. These low pressure cells are ozone collectors.  The air circulating within them morphs together to create the vortex upwards of  50 hPa. There is a very wide zone of low surface pressure between the Antarctic continent and the latitude of New Zealand to promote the sticky presence of low pressure cells.Juane SLP
  • Ozone is continuously drawn into the multi vortex structure within the generally ozone deficient core of mesospheric air. This has the effect of raising the ozone partial pressure within the core as it descends thereby actively reducing the ozone differential  between core and perimeter air. Mini vortex structures of elevated ozone partial pressure persist but only so long as they are supplied from the incomplete annular ring of ozone rich air. When cut off from a source of ozone rich air these  mini vortexes lose ozone partial pressure and become invisible until they re-connect with the source of ozone rich air.
  • New feeds of ozone rich air are created and drawn into the cone of descending mesospheric air from the ozone rich sector on a continuous basis.
  • Only traces of virginal mesospheric air that is relatively deficient in ozone can be seen within the vortex. The rate of mixing ensures that there will be much less difference between the ozone content of the air inside and outside the vortex at the 50 hPa level. Nevertheless there will always be a substantial difference in air temperature across the vortex between internal air of mainly mesospheric origin and stratospheric air outside the vortex warmer in part because it derives from the mid latitudes. As we see below, there is a marked difference in the temperature of the air above the 250 hPa level in winter by comparison with summer. This shows us the extent of the descent of mesospheric air and its involvement in the evolution of the polar arm of the Jet Stream.Temp pole

IMPLICATIONS FOR SURFACE CLIMATE

  • An increase in the intake of mesospheric air will dilute the ozone content of the ozonosphere generally. As the ozone content of the air above the polar cap is diluted the temperature of the air will fall. Large variations in the temperature of polar cap air occur on inter-annual and longer time scales. As the ozone content of the air rises and falls so too does polar cyclone activity and with it there is a change in the distribution of atmospheric mass between high and other latitudes.This is the essence of the most significant modes of climate variability observed on the planet. These modes are well documented as the Arctic and the Antarctic Oscillations.These modes involve a change in the pressure differentials driving the planetary winds and therefore change in the equator to pole temperature gradient.
  • The area to the east of the Antarctic peninsula tends to be ozone deficient and therefore the natural home for a high pressure cell of descending air. Another natural home for a zone of high surface pressure lies to the west of Chile where the ocean is very cool. A third is the Australian continent in winter. The strength of the pressure differential across the Pacific Ocean that drives the trade winds will depend on surface pressure in the broad ozone deficient zone to the west of Chile.  This is part of the ENSO dynamic in the southern hemisphere because it determines the pressure differential that drives the trade winds across the Pacific. This differential changes on decadal and longer time scales. There is a similar dynamic driving change in the planetary winds in the North Atlantic and North Pacific.
  • The strength of the west wind drift that is driven by the westerly winds in the Southern Ocean and the temperature of the waters streaming northwards on the western margins of South America depends upon the pressure differential  between the mid latitudes and the margins of Antarctica. That depends in turn on the ozone content of the air in high latitudes that is responsible for the strength of polar cyclone activity. Polar cyclone activity determines the balance of surface pressure between mid and high latitudes.

THE CIRCULATION IN THE LOWER STRATOSPHERE

Data here. http://www.esrl.noaa.gov/psd/map/time_plot/

250 hPa 30-40S

 

In the hovmoller diagram above we see a depiction of air temperature at 250 hPa. The diagram covers the year 2014 for the latitude band 30-40° south. A northwest to southeast pattern manifests  strongly in winter. This is produced when cold ozone deficient air from the equator is drawn pole-wards. That air comes from under the high tropopause that prevails in near equatorial latitudes and it is ozone deficient, NOx rich and  very cold, as cold in fact as the air that descends from the mesosphere over the pole.  It must enter the circulation in the mid latitudes obliquely rather than directly because it must push into and under warmer ozone rich air present at the same elevation due to the low tropopause that prevails in high latitudes.  The high latitude circulation is driven by polar cyclones on the margins of Antarctica. Here the air ascends and rotates faster as it ascends.  The speed of the circulation depends in part on the strength of the zonal wind that is  dependent on electromagnetic influences. It depends also on polar surface pressure that conditions the intake of mesospheric air. The polar cyclones are formed in the region between the low tropopause (8 km) that prevails in high latitudes and 100 hPa (18 km). In this zone there are marked differences in the density of the air according to its origin.  These density differences are material to the development of polar cyclones that propagate downwards to the surface and send ozone rich air to the top of the atmosphere where it accumulates at 1 hPa and spreads out towards low latitudes, This ozone rich air is entrained in the descending vortex as described above.

The polar circulation ascends to the top of the atmosphere. The tropical circulation is limited to a high tropopause. What goes up must come down and the dominant zone of descent from the stratosphere is the high pressure cells of the mid latitudes. A smaller zone of descent is via the inside of the polar vortex.

Source of map below here

descent

Notice that in this description of the way in which the wind blows I do not refer to a ‘coriolis force’. There is no such force. This is a meteorologist’s rule of thumb. Nor do I refer to ‘tropopause folding’ or ‘surf zones’  The circulation of the atmosphere is set  in high latitudes where its rate of rotation is fastest and it is a product of circumstances that manifest most strongly in winter. Its engine is located between the 300 hPa and the 50 hPa pressure levels. That engine is the difference in air density across the vortex.

Now let us look at this circulation in terms of the distribution of NOx and ozone near the tropopause.

NOX and Ozone

We are looking at a polar stereo-graphic view of the southern hemisphere with Antarctica central. The light grey line overlaid on the diagram at left traces the feathery edge of air with an appreciable NOx content. That line is duplicated, rendered in black and  overlaid on the ozone diagram at right. It is apparent that the distribution of ozone south of about 30° south latitude is entirely the product of the distribution of NOx. NOx catalytically destroys ozone. NOx is not apparent in the yellow areas but these are interaction zones where NOx has already done some work in reducing the ozone content of the air.

Let us now examine the circulation at 50 hPa and 100 hPa by tracking the passage of NOx rich cold air of tropical origin into the ozone rich warmer, less dense air at high latitudes. Let us remember that surface pressure is determined by the ozone content of the air. Surface pressure is much lower on the margins of Antarctica. That requires that cold, dense ozone deficient air must flow from the low and mid latitudes to high latitudes where the air is ascending to the top of the atmosphere as in a chimney. The return flow is from the top of the atmosphere.  We should be able to track the ingress of NOx rich air anywhere between the 300 hPa and 50 hPa pressure levels. Data is available for the 50 hPa and 100 hPa pressure levels here and is reproduced below.

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It is apparent that the air from mid and low latitudes is drawn into the circulation on the margins of Antarctica and progressively loses its separate identity in the process. At the 100 hPa level, the level of the tropical tropopause, that the great contrasts in atmospheric temperature and density are to be found. This is approximately the level where polar cyclones are formed and jet streams generated. According to the contrasts in the ozone partial pressure, temperature and air density polar cyclones wax and wane in activity, shifting atmospheric mass to and from high latitudes.

Here we are looking at the origin of the inter-annual modes of natural climate variation. But it is more than that. We are looking at the engine that drives weather on all time scales. The beating heart of this engine is ozone. The distribution of ozone is not the product of the system. The system is the product of the distribution of ozone.

 

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13 thoughts on “32 THE CLIMATE ENGINE THAT IS THE OZONOSPHERE

  1. Yes, the system can clearly be a product of ozone, but ozone is initilly produced from oxygen splitting in vast quantities so the UV is the next upstream driver. More so, ozone appears not to change temperature of surface or lower troposhpere for any length of time at all. Wheeras the ocean heat transfer via that same UV splitting energy looks more likely to produce the long term surface and lower troposhere trends….ie shorter term weather vs longer term climate. Am still open to folowing it through.

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    1. Hi Macha. Consider this situation. You are travelling in your car. Its cold. You can put on the heater or you can put on the air conditioner to further chill the air.

      Similar situation. You are at 33° south latitude. If the wind blows more often from the north you will be warmer as long as it is blowing from that direction. If it blows more often from the south, you will be colder more of the time. This is the first manner in which ozone changes surface temperature. It changes the relationship between surface pressure between the polar regions and the equator. The biggest change occurs in high latitudes where ozone heats the air forcing polar cyclone activity. More ozone = lower surface pressure in high latitudes = wind blows more often from the equator.

      The second way in which ozone changes surface temperature is by changing cloud cover and this particularly applies to any situation where the air descends. Under strong cloud cover only 10% of solar radiation reaches the surface. Without cloud cover 100% reaches the surface.

      The climate signal is warming in the winter. It is in winter that the big fluctuations in polar surface pressure occur. The polar vortex is a winter phenomenon due to the descent of mesospheric air at that time.

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  2. From here, http://ozonewatch.gsfc.nasa.gov/meteorology/flux_2016_MERRA_SH.html, it looks like the wind is always from the north and at all pressures ie equator to pole. So I cannot see that cold aircond from the south very often at all. The SH vortex is also surrounded by a ring of relatively warm water ( ocean conveyor belt) which clearly shows up in the surface temps surrounding the vortex. This too could produce strong winds in the same manner you describe for ozone effect, which in itself follows a lot like the Sam – southern annular mode. Also, given the water content, contain the required thermal mass. cause and effect versus correlation is tricky, yes?. Also, SAM and ENSO alone may well explain ~90% of global temperature changes in last 50yrs or so. Not bad given no fancy GHG modelling factorising. Sorry if I am a pain, likely going over stuff you have long reviewed and discarded.

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  3. To find a July with ozone column like 2016, I needed to go back to 2010 and 2011, here. http://ozonewatch.gsfc.nasa.gov/monthly/SH.html. the concentration Just OUTSIDE the vortex is noticebly higher than years between. This seems to delay onset and perhaps Size/ severity of the hole come our summer. Ps. I am miffed why there is so little traffic at your blogg. Is it the science or lack of idle gossip. Ha. Anyway, it blowing its guts out here. Macha

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    1. Hi Macca, yes a wild weekend. So far as the traffic is concerned….well, the nitty gritty of this subject is pretty esoteric for most people. And the people who should be interested seem to have got to be ‘climate scientists’ by virtue of their capabilities as mathematicians. One thing that I have learned in this field is that the less one massages the data with averaging techniques and the more that one looks at it in its raw form, with all of the seasonal and short term oscillations intact and fully evident, the more illuminating it can be. Have you used this site:http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl It’s a fantastic resource for anyone trying to work out the way the climate system works.

      The ‘hole’ is produced by a quirk of the circulation in the lower atmosphere during the ‘final warming’ of the stratosphere as it transitions to its summer pattern. In the process the wind direction at 10 hPa reverses. Wind speed is 400 km /hr in winter and about 5km/hr in summer. Nothing to do with chlorine compounds or temperature. That’s all bullshit. See: https://reality348.wordpress.com/2016/05/14/23-the-dearly-beloved-antarctic-ozone-hole-a-function-of-atmospheric-dynamics/ That hole has been with us for a very long time and its going to be with us for a long time to come. It was larger prior to the 1960s and should be larger in thirty years time than it is today. Now, people who don’t look at the circulation and the data will be incredulous about that statement. Too bad, I cant sugar coat it. But the statement will turn a lot of people away, those who choose what to believe on the basis of the weight of opinion rather than a dispassionate examination of the phenomenon. It’s all about following the evidence and being sure that ones observations are real rather than dreamed up and ones logic is intact.

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  4. Think I am getting the picture. ” The resulting increase in temperature is most marked in October….This is a function of ozone enhancement in the atmosphere outside the ‘hole’ and ozone depletion within, that acts to reduce surface pressure”. So now, what the heck happened around ’78-80??!. Such a step change.

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    1. Maybe this…^ Miller, AJ; Cayan DR; Barnett TP; Oberhuber JM (May 1994). “The 1976-77 climate shift of the Pacific Ocean”. Oceanography 7: 996–1002. Sea surface temps.

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      1. The Key observation from the paper: The Aleutian Low deepened causing the storm tracks to shift southward and to increase storm intensity.

        The 1976-78 climate shift occurred in the transition from the weak solar cycle 20 to the strong cycle 32. The biggest change that resulted was an abrupt increase in the temperature of the southern stratosphere consequent on an equally dramatic fall in surface pressure over Antarctica. The ozone content of the global atmosphere increased including in the Arctic (same planet after all) where the change in the temperature of the Arctic at 10 hPa in summer was about half that in the Antarctic. Not a lot of change in winter in the Arctic. The NH has an unusual distribution of surface pressure in winter that involves increased surface pressure over the continents rather than the Arctic Ocean. By late February that changes as the land masses begin to warm and pressure in the Arctic picks up. Any increase in ozone partial pressure in the Arctic strengthens the Aleutian low which is the dominant low pressure centre for collecting ozone in the northern hemisphere in winter (relatively warm ocean supports high temperature). So, the answer to the question as to what caused the shift is an increase in the ozone content of the Antarctic stratosphere. That elevated ozone (and temperature) has been falling gradually ever since. Climate science is conducted in the northern hemisphere and people there are largely unaware of anything that happens in the southern hemisphere and those who study climate science here are mathematicians and modellers who think that that modelling is very smart.

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  5. Hmm, I noted the same bit in the paper as a highlight too. The predominance of poorly interpreted global averaging in most papers is disturbing too. Whilst being a useful trending tool, once such a mathematical operation is done it loses its true physical property value, IMO. ie. Global temperature might apply to gross energy balance between earth and space, but provides little within earth itself where the climate action is within each of the hemispheric zones. Simply, pressure is always proportional to volume x temperature and volume is proportional to molar mass…but thats nothing new. The size of the up coming solar cycle will be interesting.

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    1. Macha, I spent years averaging data in one way or another and calculating anomalies. Not until I started looking directly at raw data by the month did the magic penny drop. If daily data were available one could get to the nitty gritty of what happens as a pressure system passes a line of longitude. But there are animations that help…especially of geopotential height. When you see GPH you just need to realize that it is ozone at work and that means surface pressure and wind.

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  6. “t’s all about following the evidence and being sure that ones observations are real rather than dreamed up and ones logic is intact.”

    That line really resonates with me.

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    1. Hi Rob, Never precluding of course that you learn to better connect the dots as you go along and that the matter is complex so that you can’t actually get to the bottom of it…you keep learning. Questions continually arise. For instance Macha’s question about the 1976-8 shift and the reference he pointed me to highlighted the manifestation of that shift in the north Pacific Aleutian Low.

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