40 A WIND FROM THE SOUTH AND A WIND FROM THE NORTH

Ecclesiastes 1:6
The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to his circuits.

This post revises key concepts that relate to the evolution of climate. Good teaching is about saying it again in slightly different ways until it sinks in. This caters for the students who can’t tune in at a particular time and many others whose perceptual frameworks are sort of ‘frozen’. Its also possible that the message can be delivered without the  necessary flair.

Knock-knock.  New idea. Fundamental to the nature of Earth is the difference between  the warmth of low latitudes and the cold of high latitudes.  Without the redistribution of energy by wind and water the extent of the habitable latitudes would be tiny. In the tropics there is little variation in the nature of the air from day to day. But in the mid and high latitudes change is the rule.  When the wind changes in a systematic fashion  to establish new states, we have climate change. The further we depart from the equator, the greater is the change that is experienced.

The air moves from zones of high to zones of low surface pressure. Pre-eminent in terms of low surface pressure is the Antarctic Circumpolar Trough. It is the zone coloured orange in figure 1.

Annual SLP
Figure 1

Kalnay et al’s reanalysis of 1996 to be found here. shows the evolution of surface pressure by latitude over time and is presented in a graphical format in figures 2 and 3.

July pressure
Figure 2.
January pressure
Figure 3

Plainly, the work that is done in redistributing energy across the latitudes is dependent on the evolution of surface pressure in the Antarctic Circumpolar trough and to a lesser extent the latitudes north of 50-60° north.

 

40-60-n-and-s-t-air
Figure 4

Figure 4 plots the temperature of the air as it evolved in the year 2015 at  500 hPa at 40-60° of latitude in the northern hemisphere at left and the southern at right. Plainly there is a north-west to south-east orientation in the movement of the air masses as  the atmosphere super-rotates about the Earth in the same direction that the Earth rotates, but faster. The speed of rotation increases in the southern hemisphere where the angle of attack is more aligned with the parallels of latitude. The air spirals from north to south at all latitudes.Warmer parcels will have an ascending  tendency while colder parcels will be descending.

THE IMPORTANCE OF POLAR CYCLONES

New Concept: It is polar cyclones that are responsible for the intensity and evolution of the circumpolar trough.

A core theme of this work is that Polar Cyclones are energised by warm, low density cores in that space where the troposphere overlaps with the stratosphere. Differences in the ozone content of the air gives rise to differences in air density. A chain of cyclones on the margins of Antarctica   give rise to a rapidly circulating polar vortex in the stratosphere. There are no limits to convection in the stratosphere.

In summer the air rises to the limits of the atmosphere directly over the continent of Antarctica but in winter there is descent. A rising cone of air surrounds the zone of descent. This cone is sometimes described as a polar vortex. The cone begins at 300 hPa over the circumpolar trough and widens to take in the mid latitudes at the highest levels.

The upper troposphere/Lower stratosphere in the region of the circumpolar trough is characterised by intense mixing of air from diverse origins, the troposphere, the stratosphere and the mesosphere.

Between October and March the cone of ascending air below 50 hPa tightens like a hangman’s noose bringing air from the troposphere to the pole, creating an ozone hole, the falling away of surface pressure at this time of the year associated with generalised ascent over the Antarctic continent and so excluding the flow of air from the mesosphere that descends throughout winter.

That the circumpolar trough is due to differences in the ozone content of the upper air should be non-controversial.

THE DENSITY OPACITY OF THE GREEN BLOB

The circumpolar trough is an unremarkable aspect of the atmosphere in the view of UNIPCC. The significance of its presence is  unappreciated. This is not an unusual state of affairs in the annals of humanity. In fact,  ‘Climate Science’ has not leaned a lot about atmospheric dynamics since the time of the pioneer Bjerknes who published a work on the near surface characteristics of polar cyclones in 1922.

Bjerknes

It is realised, at least in meteorological circles, that a trigger is required for the formation of low pressure cells of rotating air  in the region of the circumpolar trough. That trigger  is an upper level trough, a mass of warmer, low density ozone rich air.

In  1922 it was not apparent that the most vigorous winds are located in the overlap between the stratosphere and the troposphere. Neither was it apparent that cold ozone deficient air  from both the mesosphere and the tropical troposphere are drawn towards the circumpolar front in the space shared by the upper troposphere and the lower stratosphere.

In fact the concept of a ‘stratosphere’ was pretty new in 1922. In many respects we have not moved on from that position despite the passage of 100 years. Indeed much that was known prior to the 1970’s has since been forgotten in parallel with the increasing concern that man and the environment in which he lives are  incompatible entities. Educators went off in socially responsible directions. A fabulous gravy train  was created for scientists and space agencies and all those who aspire to gain their daily bread by looking after the environment, painstakingly monitoring the activities of a an every increasing panoply  of despoilers, at one end mighty global corporations and at the other the humble cow that provides the milk for your morning cereal irresponsibly farting in  its field of green. Such is the work of the modern missionary.

The intensification of polar cyclones in winter, and the consequent lower surface pressure at that time of the year is due to the proliferation of ozone. Gordon Dobson observed in the 1920’s that, in high and mid latitudes low surface pressure identifies areas with high total column ozone. Dobson measured wind velocity and discovered that the strongest winds were not at the surface but in the region of the tropopause. The tropopause is kilometres lower when surface pressure is low than when surface pressure is high. This circumstance may be described as an upper level ‘trough’, a zone of  reduced air density that shows up in elevated geopotential height contours. Had Bjerknes apprehended the structure of the upper air we would not now be worrying about carbon dioxide in the atmosphere. We would be aware that the source of long term climate change, the source of decadal variations, the source of inter-annual variations and indeed our daily weather lies in variations in the ozone content of the stratosphere. We would  be at peace with the notion that our ‘rather too cool for comfort’ planet gains and loses energy according to change in the extent of its cloud cover.

There is so much to learn.

 

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13 thoughts on “40 A WIND FROM THE SOUTH AND A WIND FROM THE NORTH

  1. “There are no limits to the convection in the stratosphere.”

    So true! During the ice age all of Canada and many of the
    northern states were under a mile of ice. Just imagine the
    magnitude of this vortex of descending air. For 90,000 years
    this ice advanced and retreated, suggesting an incredibly
    powerful exchange of atmospheric pressure between the two
    hemispheres.
    I think ren has got it right, when he points to solar wind as a
    major contributor. Solar wind is strongest when the sun’s
    magnetic field is strong. Cosmic rays are most abundant
    when the sun’s magnetic field is weak.
    There appears to be a back and forth going on that is
    linked to overall atmospheric pressure shifts.

    Like

    1. TL Mango,
      As to why the ice advanced in the northern hemisphere during the ice ages and whether there was a parallel advance in the southern hemisphere I have no idea. In my schema the ozone content of the air, being responsible for polar cyclone activity and creating the differential pressure that brings a rush of warm air to the poles, also driving the westerly winds that are responsible for the rotary circulation of the ocean that brings warmer moister conditions to the east side of the continents together raise the temperature in high latitudes limiting the advance of the ice. Now, if the ice ages became successively less severe over time one might imagine that this could be due to a gradual increase in ozone partial pressure that establishes a ‘stratosphere’. That in turn limits the ingress of short wave radiation to the biosphere making life more secure. If that enables more plants to survive it means a greater supply of water to the atmosphere, perhaps more cloud cover, more precipitation, more land receiving precipitation to support plant activity.

      Other factors enter into it like the distribution of the continents, the current setup being responsible for the dominance of the Antarctic in determining the evolution of surface pressure and the planetary winds.
      The coolest temperatures at the surface are experienced in Siberia in winter. It’s due to the descent of mesospheric air. The extent of land at the poles determines the increase in surface pressure that occurs in winter and that governs the extent of that descent. Ice probably does the job as well.

      Yet other factors relate to the observations of Milankovich that affect the intensity of solar radiation at the limits of the atmosphere.

      I believe that fluctuations in cloud cover may be important. The current distribution of land dictates that cloud cover is least in June when the Earth is furthest from the sun. Currently, global cloud cover is greatest when the Earth is closest to the sun limiting the incidence of radiation at the surface and the uptake of energy by the southern oceans. A generally colder climate would limit the distribution of plants, reduce the flow of water into the atmosphere and reduce cloud cover in southern hemisphere summer and promote a warming of the ocean.

      What could increase cloud cover? One thing would be the extent of vegetation that pumps water into the atmosphere. Increase it and the supply increases. But the atmosphere can hold moisture only according to its temperature. In an ice age there is much less vegetation in high latitudes, less vegetation pumping water into the atmosphere, drier air, less precipitation but there could nevertheless be much the same quantum of cloud.

      Lots of speculative possibilities. What do you think is responsible for ice ages? Pressure difference is the key to what?

      Like

  2. This has to be the best imagery on the subject ever written..
    “Educators went off in socially responsible directions. A fabulous gravy train was created for scientists and space agencies and all those who aspire to gain their daily bread by looking after the environment, painstakingly monitoring the activities of a an every increasing panoply of despoilers, at one end mighty global corporations and at the other the humble cow that provides the milk for your morning cereal irresponsibly farting in its field of green. Such is the work of the modern missionary.”
    What a biblical laugh it gave me. Brilliant work.

    TLMango….I try to observe at face value rather than by preconceived ideas. Anything I have written is given as Freely – just as Erl has provided with his enormous tenancity and grace throughout this series of blogs. I reference this site wherever I see the IPCC meme. Perhaps utube or vines or twtter is needed for something more viral to take effect. Cheers.

    Like

  3. Hi Erl,
    I’m pushing a theory that ice ages are a result of a
    solar system wide decrease in magnetic field strength.

    The reason pressure difference is the key:
    The greater the pressure differences the more the
    whole transport process is accelerated. The more the
    transport process is accelerated the less capable the earth
    is of retaining its stored heat.

    An ice age must be a time of incredible pressure differences
    and a huge transport of atmospheric mass. Imagine that it is
    5 below outside and someone left the front door open.

    Like

    1. TL Mango,
      If the ice age is simply a result of a slowing of the atmospheric circulation that brings warm air and water to increase the temperature in high latitudes then we could infer that this would follow from a reduction in stratospheric ozone. That would reduce the contrast in air density in the region of the ‘tropopauses’. The Jet streams would slow. Polar cyclones would lose intensity. Surface pressure would rise in high latitudes and perhaps begin to exceed that at the equator in which case air would flow from the poles towards low latitudes. Polar ice caps would increase in surface area.

      If high latitude ozone is a product of cosmic ray activity and a strong sun so alters the local interplanetary magnetic field so as to exclude cosmic rays then the ice age scenario would be a product of strong solar activity.

      If, on the other hand the interplanetary Magnetic Field changes as a result not so much of activity levels changing on the local sun but a change that is external to the solar system of which Earth and our local sun is part so as to reduce the intensity of cosmic rays so reducing the creation of ozone in high latitudes we would look to the external environment for the source of this change. That’s the way I would be looking because we have recently seen strong solar activity in cycle 19 of 1955-65 and warm conditions in the mid latitudes due to low surface pressure in the Antarctic circumpolar trough.

      There is also the possibility that Cosmic Ray deposition is affected by the Earths changing magnetic field and the movement of the atmosphere itself.

      Theory could be tested by looking for coincidences in the ice cores.

      http://www.antarctica.gov.au/magazine/2006-2010/issue-14-2008/science/cosmic-clues-into-solar-activity-and-climate stresses atmospheric effects on cosmic ray deposition.

      The length of heat storage is affected by cloud cover over land versus the sea but in any case its not long. I doubt that change in this factor alone could result in an ice age. Why: because the atmosphere is very thin and its a very efficient means for energy removal. But for the atmosphere I think the Earths surface would be very much warmer than it is.

      A brief look at the literature suggests that ice ages are accompanied by increased GCR deposition. This could be as a result of a concentration due to change in the atmospheric circulation above the Antarctic.

      Like

  4. Hi Erl,
    No, an ice age isn’t the slowing of the circulation.
    It is an acceleration of the circulation.
    Maybe my choice of words caused some confusion.

    Like

  5. “A brief look at the literature suggests that ice ages are
    accompanied by increased GCR deposition.”

    Ice ages are a time of a prolonged weakness in magnetic field
    strength throughout the entire solar system. The sun and the
    planets are in circular orbits and the solar system is in a relaxed
    state. An inter-glacial is the return of eccentricity, acceleration,
    strong solar activity and a strong dynamo within the earth’s
    inner core.
    During an ice age the sun’s magnetic field would be very weak.
    There would be massive amounts of cosmic rays. Ozone production
    would be off the charts, but it would all get destroyed because of an
    hyper accelerated transport process.
    During an inter-glacial the transport process takes regular breaks,
    large amounts of ozone can accumulate in the lag time just prior
    to the vortex shutting down.

    Like

    1. TL Mango, Not sure what you are describing here. It might help me to relate to what you are describing if you could set out
      1. The forces responsible for the transport process during a glaciation.
      2. The direction of flow of the hyper accelerated transport process.
      3. The agents for or means by which ozone is destroyed.
      4. ‘The vortex’.

      Like

  6. Hi Erl,
    “1. The forces responsible for the transport process during a glaciation.”

    During an ice age it is para-magnetic oxygen that fuels the transport.

    visit HarryTodd.org
    Oxygen is 21% of the atmosphere and para-magnetic. It is attracted to
    a magnetic field and this attraction grows increasingly stronger as
    temperatures become colder. This suggests that during an ice age there
    are times when there is a runaway cooling effect and this is because solar
    activity is just too weak to stop it.
    Ozone is dia-magnetic and wants to be where the magnetic field
    is weakest but the flow is one way and ozone is carried away in the
    process.

    During an inter-glacial, solar activity is high and the earth’s magnetic field
    is strong. Para-magnetic oxygen is attracted to the strong magnetic field
    and wants to be where the field is strongest. But strong solar activity via
    the solar wind is restricting the flow. Now, para-magnetic transport serves
    to increase pressure and may even help in restricting the outflow. It appears
    that the transport process during an inter-glacial is very different from that of
    an ice age. It also appears that the inter-glacial period is regulated by the
    circulation that is associated with infra-red heating of ozone.

    Like

  7. Hi TLMango, it took me a while to read harrytodd.org. Welll…truth be told I have only skimmed it so far.
    I do like the concept. As a chemist it appeals to my sciencey knowledge.
    ” Earth’s wandering magnetic poles force global climate change.”.
    I can see how it can easily sit mutually within Erls work here.. Or vice versa, Erls work can easily sit within todds. Ie is not exclusive and both can work simultaneously.
    The core premise for me in both is that the behaviour of the SH vortex, more than any other zonal area, has a driving mechanistic influence over global climate in time frames relevant to what we feel. Ie from a couple of days out to a couple of decades.
    There are some unresolved chicken and egg issues but I am not hung up on them, for now.
    Anyway thanks for the site link, back to shore up the skimming.

    Like

  8. Macha,
    Thanks to blogger ‘pat’ at JoNova’s weekend unthreaded
    for pointing out this new paper:

    Stolper, Daniel A. et al., (2016) “A Pleistocene ice core record of atmospheric O2 concentrations”
    Science, 353, p 1427 – 1430.

    DStolper.com

    link:
    “Research At Princeton”
    blogs.princeton.edu/research/2016/09/23/

    Stolper examines O2 concentration over the last 800,000 years.
    But there may be more here than meets the eye. Shifting para-
    magnetic oxygen could easily be misinterpreted as a variability
    in oxygen levels.

    Like

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