The linkage between cloud cover, surface pressure and temperature

For the albedo data in this presentation I am indebted to Zoe Phin at. https://phzoe.com/2021/06/01/on-albedo. As per usual the temperature data comes from: https://psl.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl

Atmospheric albedo is due to particles that reflect visible wave lengths in the spectrum of light emitted by the Sun. This reduces the light that reaches the surface of the planet. Reflection in the atmosphere is due to cloud, and my gut feeling is that the strongest variability will be in the cloud that is in the form of multi branching crystals of ice that create a large surface area in relation to their mass. With a lapse rate of 6.5°C per kilometer, the elevation required to form ice cloud is no more than 3 km over the bulk of the planet and 5 km at the equator. Much ice cloud is seen to be stratified due to localized cooling at a high altitude. With 90% of the atmosphere below 10 km in elevation and ice cloud extending into the stratosphere, its obvious that albedo due to variation in ice cloud density might play a very important part in determining surface temperature. Orthodox climate science tells us that this cloud warms the surface by back radiation. I think differently. The higher the elevation of the cloud the more its density will vary according to the ozone and H2O content of the particular layer involved. And this type of cloud is always layered. It is estimated that about 90% of the albedo of the Earth is due to cloud. Surface features don’t get to play a big role due to the ubiquity of cloud. The question is, which sort of cloud plays what role.

Using satellite instruments that intercept light that is reflected, it has been possible, for more than twenty years, to document atmospheric albedo and chart its variation. So far as I am aware nobody has thought to juxtapose that data with surface temperature. Why? Because of the almost universal assumption that the temperature at the surface is determined by back radiation from the atmosphere, including from cloud, with ice cloud at a high altitude presumed to be partly responsible.

Albedo is measured as the proportion of solar radiation that is reflected towards space with no change in wave length. As we see above, there is a seasonal cycle.

Albedo is at its minimum in August and it peaks in December. The secondary hump in albedo between April and August is explained by the increase in cloud associated with the South and East Asian Monsoon. Eastern China receives about 60% of its rainfall between May and August. The Indian Monsoon is frequently initiated on 1st June. So there should be no doubt that albedo varies with cloud cover.

The data indicates that, between 28% and 31% of solar radiation fails to reach the surface according to the time of the year, due to reflection by atmospheric constituents.

Consider the following argument. As we see above, the temperature of the Earth peaks in July-August. This is coincident with albedo at minimum. The July-August peak in temperature is due to the evaporation of cloud as the land masses of the northern hemisphere heat the atmosphere, driving the dew point down and maintaining more water vapour in its invisible, non reflective, gaseous form. On a regional scale land returns energy to the atmosphere tending to clear the sky during the daylight hours but allowing cloud to return in the late afternoon and evening. Vegetation supplies moisture to maintain cloud so that a fence separating cleared land from native vegetation is frequently observed to be also a dividing line for cloud. So, we know that the supply of moisture and the extent of back radiation from the land surfaces play a big role in determining the presence of cloud. Globally, tropical rain forests in the Congo and the Amazon and across the ‘Maritime Continent’ are the chief sources of atmospheric moisture measured as Total Precipitable Water.

Solar irradiance is 6% weaker in July than in January due to orbital considerations. Now get this! Paradoxically, the temperature of the globe peaks when solar irradiance is weakest. A 5.7% decline in albedo between January and July compensates for the 6% deficit in solar radiation and on top of that, delivers the thumping 2.5°C benefit by comparison with the southern hemisphere. Obviously, this is a feedback driven process that relates to the distribution of land and sea.

This paradox is instructive. Take away the cloud and surface temperature increases. Put the cloud back, and the temperature plummets. Adding the cloud back negatively impacts the Southern Hemisphere in its summer giving rise to cooler temperatures at every latitude than is experienced in the same latitude in the northern hemisphere. The notion that cloud warms the surface via back radiation that is incorporated into the mathematical equations that constitute climate models is erroneous. Cloud normally comes in warm moist air from the equator. Perhaps that is the source of this error.

Over the sea, radiation goes straight into the receipts ledger of Earths energy budget because the sea is transparent. Radiation that falls on land tends to be returned to space with expedition. That is what a comparison of the temperature of the Northern versus the Southern Hemisphere demonstrates.

Its important to realise that any variation in albedo over the land starved Southern Hemisphere that occurs between July and April will be critical to the Earths energy budget.

We need to know what lies behind the variation in albedo including an answer to the ‘where and ‘why’ questions. We can begin with a study of variability by month of year.

The diagrams below are a simple method of assessing the nature of variability in albedo according to the month of the year.

Patently the variation in albedo is a cyclical phenomenon and we have to look for a mechanism to explain it. If we can not explain it and account for it properly we have no business attributing climate change to the works of man. or anything else for that matter.

The interpretation delivered below is based on the reality that the atmosphere of the Earth is in part ionized, especially so in winter and at solar minimum due to the impact of intergalactic cosmic rays. The atmosphere exists in a magnetic field that extends into Space that we call the Magnetosphere. The Earths magnetic field couples to the interplanetary magnetic field to the greatest extent in March and September when the axis of the Earths rotation is at right angles to the plane of it’s orbit.

First see diagram 3. Notice that the pattern in September is a mirror image of that in March. Its hard to make any sense of what’s happening as the Antarctic begins to dominate the evolution of the planetary winds, via its determination of the evolution of surface pressure, between April and August.

Close inspection reveals that the whole of period variation of albedo in October is greater than any other month. In figure 1 we see that the data for October is a mirror image of that in January.

September shifts the August pattern towards what it will become in October. In other words, October magnifies and exaggerates the nature of the variation in albedo that is initiated in September. In November and December, the October pattern is maintained but softened.

November is a very important month for climate. It is in November that the changeover occurs between the Antarctic and the Arctic in the phenomenon known as the final stratospheric warming. The high altitude circulation over the Antarctic changes from descent to ascent with a 180° swing in rotation from ‘west to east’, to ‘east to west’ with the summer rotation a pale version, in terms of the energy involved, of that in winter. With a cessation of descent associated with a fall in polar surface pressure, the temperature of the stratosphere warms to the point where, over Antarctica, it is commonly 20°C warmer at the stratopause than at the equator where the pressure of ionization is most severe. Patently, it is not ionization by solar energy that heats the stratosphere, it the absorption in the infrared by ozone. There is a less exaggerated variation of albedo in November. But, the pattern of variation in November is still like that in September. November albedo is a regular 9-10% increase on that in September. The Earth system is throwing up a cloud umbrella as the Earth gets closer to the sun and solar irradiance gets stronger.

The variation in January is a mirror image of that in December and the January pattern persists into February. The pattern in March is different to that in February, sometimes opposed. However, the disturbance seems to be temporary because the pattern in April reverts to the January-February type.

In September the organizing principle transitions to the form that persists between October and December.

March and September, the months where the Earths atmosphere couples most effectively with the Interplanetary magnetic field are diametrically opposed. It’s as if the atmosphere gets a jerk that temporarily disturbs its habits. The reversion from Arctic to Antarctic control of the global atmospheric circulation occurs in late March, muddying the impact of the coupling of the atmosphere with the interplanetary magnetic field at that time. The ionization of the Arctic atmosphere peaks in January rather than in March. In contrast, the September coupling occurs at a time of strong ionization, and a peak in ozone partial pressure. Ozone is not neutral, electrically speaking. The critical thing to remember is that, via this process the atmosphere is set up to rotate like an electric motor.

There has been a steep recovery in Albedo since 2019 in the months from September through to December. It’s plain that there is an organizing principle that lies behind the variability in albedo and it is very likely to be the response of the atmosphere to the interplanetary magnetic field. Just consider this. The atmosphere rotates in the same direction as the Earth, but faster. Those who are interested in this phenomenon talk about atmospheric angular momentum and a variation in ‘time of day’ that appears to correlate with changes in the planetary winds.

The connection with surface pressure

The flux of surface pressure in high latitudes. directly determines pressure in the mid latitudes in a manner described as the ‘Annular Modes’ phenomenon. Along the equator any increase in surface pressure in the south east of the Pacific Ocean is associated with a fall in temperature as cold water either upwells to the surface along the South American coast or upwells and is is transported westwards along the equator. Where waters are not affected by the mixing of cold with warm or warm with cold, surface temperature varies directly with surface pressure. Along the equator surface temperature rises as atmospheric pressure falls. Under a high pressure cell where the waters are not affected by mixing processes, as the surface pressure rises, so does the temperature of the water, due to a reduction in cloud albedo, exactly the opposite to what occurs at the equator. When this occurs over land, as in the northern hemisphere in summer the impact on surface temperature is immediate and strong. Over the sea, the impact is slight because the ocean absorbs energy to depth.

On a month by month basis surface pressure in the mid latitude high pressure cells of the southern hemisphere depends on pressure in the Aleutian Low and the Icelandic Low. When these cells are are active atmospheric mass accumulates in the high pressure cells of the mid latitudes of the Southern Hemisphere, especially that in the South East Pacific adjacent to Chile. Whereas the Antarctic trough is the background driver of surface pressure across the globe, the vigour of the Aleutian Low has a surprisingly generous impact on the high latitudes of the southern hemisphere between January and March. This directly impacts the ENSO phenomenon via a strengthening of the Trades.

Pressure is normally high in the southern high pressure cells in winter due to the pronounced heating of the northern hemisphere and enhanced polar cyclone activity in the Antarctic trough. This creates a wide zone in the mid latitudes where cloud albedo is naturally low. A strong Aleutian trough delivers strengthening trade winds in the Southern Hemisphere via a boost to the high surface pressure in the Chilean High. The loss of cloud albedo as these high pressure systems expand in surface area, creates a situation where temperature in the mid latitudes increases as it falls across the equator. The enhanced pressure differential between the Chilean High and the Maritime Continent, traditionally monitored by observing an increase in surface pressure in Tahiti against a relatively static pressure in Darwin drives the cooling along the equator. Paradoxically, La Nina is associated with almost invisible additions to the receipts ledger of the Earths energy budget, under the high pressure cells of the Southern Ocean, that is add odds with the evolution of tropical and global surface temperature.

In this way, the Southern Hemisphere is set up to either receive or to reject solar radiation as cloud cover is rapidly growing after the August minimum through to the December maximum. The Southern Hemisphere is mostly ocean and is known to transport energy to the northern Hemisphere, via the diversion of tropical waters northwards due to the arrangement of the land masses.

The diagram below indicates very little change in surface temperature in the southern hemisphere in December when the northern hemisphere is at its coldest and global albedo peaks. The consistent warmth of northern summer in the highest northern latitudes, is due to the invariable surface area of the continents that are responsible for reduction in albedo in mid year. But it is the Southern Hemisphere, picking up energy as the northern hemisphere cools in the last half of the year. that provides the warmth that lengthens the growing season in the northern hemisphere by elongating Summer and Autumn and rendering northern winter warmer than it otherwise would be. The ocean currents that provide this benefit are well known but the source of their variability has long been a matter of speculation.

It’s important to realize that this is a reversible process. Its entirely possible that an increase in albedo affecting the mid latitudes of the Southern Hemisphere will cut off the flow of energy from the southern to the northern hemisphere. Unless there is warming in Southern Hemisphere winter the Northern Hemisphere will see its supply of energy from the south cut off. The gain in temperature seen above, should not be taken for granted. It will not necessarily continue.

Polar regions have lost atmospheric mass over the last seven decades, piling it up most strongly in the mid latitudes. This is assisted by increased convection at the equator. Nothing that is inherent in the Earth system, defined to exclude the influence of the Interplanetary magnetic field, can explain this. The increase in pressure in the mid latitudes affects the differential pressure that drives the South East Trade winds initiated from May through to December and either building or falling away in Arctic winter according to the activity in the Aleutian Trough.

The differential pressure driving the North Westerly winds of the Southern Hemisphere is superior to that driving the Trades and has been increasing apace, over the last seventy years. The differential pressure driving the Westerlies peaks in the middle of winter as surface pressure is enhanced in the mid latitudes against a relatively invariable Circumpolar Antarctic Trough that maintains a resounding planetary low in surface pressure all year round. The increase in surface pressure in the mid latitudes opens an atmospheric window according to the area that exhibits high surface pressure and relatively clear skies. The Trades and the Westerlies come from the same source, the share going to east is unstable a possible subject for another post.

The initiator of variation in ENSO is the high latitude troughs in surface pressure in both hemispheres especially attached to the vigour of the Aleutian trough from October onwards through Southern Hemisphere summer. ENSO is not albedo neutral but the change occurs, not at the equator, but in the mid latitudes.

The movement on the center of convection across the Pacific is a consequence of an increase in the temperature of waters in the East of the Pacific ocean and of no great significance in itself. This is a booster rather than an initiator of the ENSO event. There is little variation in albedo attached to the movement in the centre of convection. The process is started and driven from high latitudes, background condition determined by the Antarctic trough and the month to month swings by the Aleutian Low.

The obvious thing to ask is: How does the variation albedo relate to global temperature?

In the diagrams below the albedo axis on the right, is inverted. As albedo falls away, temperature increases. The relationship is watertight. No other influence needs to be invoked other than ENSO which throws a spanner in the works unrelated to the underlying change in the Earths energy budget.

The relationship between global albedo and surface temperature is less disturbed by ENSO at 20-30S Latitude, the latitudes where the variation in albedo is likely to be directly related to change in surface pressure.

The tropics distort the evolution of global surface in a manner that is unrelated to albedo. Temperature increase in the tropics is important to the global statistic because the circumference of the Earth is greatest in low latitudes. However, tropical variability relates to a mixing phenomenon of cold with warm water that has little to do with albedo and the Earths energy budget. The temperature of the Eastern Pacific that is normally about 8°C degrees cooler than the waters in the West increases in the El Nino phase. But essentially the increase in the East brings temperature to the point where the difference between the East and the West is, for a brief interval, reduced, or eliminated. The result is a leap in global temperature when the high pressure cells in the mid latitudes are contracting and albedo is increasing.

See below

It follows that average global temperature is a not a good guide to the status of the Earths energy budget.

In high latitudes temperature is dependent, not on the ENSO phenomenon or even albedo, but rather the degree of penetration of flows of cold air originating from the Arctic and the Antarctic and that of warm air travelling pole-wards from the mid latitude highs towards the Polar Lows that bring these air masses together. The chief variable here is the surface area occupied by LOW PRESSURE cells (polar cyclones, extratropical cyclones) in high latitudes and the balance of pressure between source and sink with reversals a fact of life. The cooling of high latitudes in the southern hemisphere relates to this phenomenon. Variability in the polar lows occurs on very long time scales. Surface pressure on the margins of Antarctica has been falling for seventy years and the area affected by reduced surface pressure has expanded northwards, especially in winter.

At times when the interplanetary field is less disturbed by solar activity, as we have seen in the most recent solar cycle, large swings in albedo should be expected.

Ruminations

Land and sea surface temperature is very sensitive to albedo on all time scales. Variation in albedo, accounts for the change in surface temperature over the last 20 years, to the exclusion of any other mechanism.

This is a lesson in the the desirability of observation, measuring what is observed and making an effort to understand the mechanism responsible for change. The Arctic Oscillation is well correlated with geomagnetic activity. Shifts in atmospheric mass between the high and mid latitudes change the planetary winds and this is the prime source of change in weather and climate on inter-annual, and longer and decadal time scales. What has been lacking is a close observation of the mechanics of the circulation of the atmosphere in high latitudes in winter and its evolution over time, that is primarily determined in the stratosphere.

Ozone is a greenhouse gas too. There is less ozone than carbon dioxide. But there is enough ozone in the air to impart sufficient kinetic energy to all atmospheric constituents to reverse the lapse rate at the tropopause. The partial pressure of ozone increases in winter when the sun is low in the sky and the short wave radiation that splits the ozone molecule is attenuated. The Antarctic circumpolar trough, the Aleutian Low and the Icelandic Low are made up of one or more polar cyclones. These cyclones can elevate ozone to to the 1hPa pressure level. A polar cyclone that is due to absurdly steep density gradients in the lower stratosphere/upper troposphere, can propagate to the surface because, the surface is simply not very far away. It is in the stratosphere, at Jet stream altitudes, and in the vicinity of polar cyclones, that the climate engine can be found, driving the circulation of the atmosphere. If you are looking to find the engine of climate change at the equator or via ENSO it won’t be there.

What goes up must come down. It (ozone) comes down in the mid latitude high pressure cells that pay scant respect to mans conceptual differentiation between ‘troposphere’ and ‘stratosphere’. The importance of ozone is derived from the fact that it is the only greenhouse gas that is not uniformly distributed and secondly, the virtual absence of ozone in the very cold air descending over the Antarctic, and the Arctic when polar pressure is sufficiently high. The volume of descent of this very cold air is not as important as the maintenance of a steep gradient of temperature and density where the two air masses converge. The notion of a ‘Front’ where these air masses meet, is unphysical. The air rotates in what might be deceptively described as a ‘cold core’ polar cyclone’. In fact the warm core starts at about 500 hPa. There is no ‘troposphere’ at high latitudes. Tropospheric air re-enters high latitudes to establish an ‘ozone hole at Jet stream altitudes in spring. The air that is of tropospheric origin has a high NOx content. Its not there during the winter season.

The descent of ozone into the troposphere has implications for atmospheric albedo. The climate shift of 1978, evident in the evolution of tropical surface temperature in the diagram above, was due to a breakdown of the Antarctic circulation that delivered a steep increase in the temperature of the stratosphere and upper troposphere globally, a subject for another day.

It can be observed that a map of total column ozone is also a map of surface pressure. It is the kinetic energy acquired by ozone aloft that is responsible for low surface pressure. It is difference in near surface pressure that appears to drive the winds. But in a polar cyclone, air density gradients are at their steepest between 500 and 50 hPa, not at the surface. The driver is aloft, not at the surface.

Notions couched in terms of ‘forcings’ of surface temperature based on radiation theory pay no respect to the complexity of the atmosphere and cannot explain the evolution of surface temperature. CO2 has nothing to do with it whatsoever. There is virtue in the study of geography even though its very old fashioned. A study of the geography of the atmosphere is good to combine with a knowledge of the manner in which the temperature and density of the atmosphere has evolved over time, at each pressure level in all latitudes. The temperature of air depends upon where it comes from. That changes systematically over time and with it, albedo.

The parameters that are important to the determination of surface temperature evolve, as does everything in the natural world. The Earth is not an Island unto itself. Unless we identify the correct parameters and study the linkages, the climate system can’t be modelled. When humans pursue ideological objectives its quite common the see them rewrite science to suit their purpose. But, who in their right mind could ignore the importance of cloud as a determinant of surface temperature.

The immediate future

This data above indicates that the change each months data from one year to the next is systematic and progressive, even in the space of 20 years. The ‘clumping’ of several months together all moving in the same direction occurs in the low points of solar cycles. We can see that over the last twenty years the tendency for the variation in albedo between months to be self cancelling, is diminishing. The recent tendency for more grouping in the last half of the year has produced wide swings in surface temperature that are independent of the ENSO phenomenon, affecting the mid and high latitudes rather than the tropics. This week Melbourne experienced its coldest, temperature on record. Some parts of Victoria received half their annual rainfall in two days. Swings to extremes are to be expected when the interplanetary magnetic field is least disturbed during solar minimum and during low magnitude solar cycles that are less disturbing of the interplanetary magnetic field.

The progression of change in March and September is worth examination:

The trend is for albedo to increase in October and for the swings to be wider since 2017. The situation in March is the opposite. The swing in October is more capable of changing the course of global temperatures than that in March. The trend in September-October has, in the past, been maintained through to December. These are important months for both hemispheres.

The big unknown is how the impact of a change in polarity of the Interplanetary Magnetic field, currently underway, impacts the system. Perhaps a person who knows more about electricity and magnetism than I do, can answer that question. Will the next solar cycle be stronger or weaker. If its the former, the Interplanetary magnetic field will be thrown into disarray and its impact on the atmosphere will not have a strong central tendency, to drive albedo either one way or the other.

My gut feeling is that the tendency for albedo to increase will not be turned around for a couple of solar cycles.

Does carbon dioxide cause the planet to warm? The cooling that’s in process. Where and why.

Let’s start with what can be observed. Tahiti lies within the margins of a large zone of high surface pressure that tends to be centered over the Pacific Ocean to the west of Chile.

The extent of upwelling of cold water in tropical latitudes, that account for 36% of the surface of the Earth, conditions global surface temperature. The litmus test for the current state of the atmosphere that is thought to determine the extent of this upwelling, is the difference in atmospheric pressure between Tahiti and Darwin that is encompassed in the Southern Oscillation Index. However, as we see in the diagram above there is a strong inverse relationship between atmospheric pressure in Tahiti and sea surface temperature in the Nino 3.4 region. As pressure increases, temperature falls. The third element shows that pressure swings more widely in January than in September. However, pressure in September exceeds that in January and the peaks in September frequently precede the peaks in January. In Nautical terms Antarctica generates the swell while the Arctic is responsible for the chop.

The distribution of atmospheric mass, determining local surface atmospheric pressure, is driven from the winter hemisphere. January and September are the months of greatest variability on inter-annual, decadal and longer time scales. The handover months, when variability is least, are November and April. Essentially, as pressure falls in the Antarctic trough, the Icelandic or the Aleutian Low, it increases everywhere else.  This governs the differential pressure that drives the Trade Winds and the Westerlies and determines whether cold air outflows from the poles or warm air displaces cold air in the Arctic and the Antarctic. As surface pressure increases in the mid and equatorial latitudes, colder water appears at the surface in the tropics. Local sea surface temperature varies inversely with local surface atmospheric pressure as is evident above and below. As pressure rises (downwards on the right hand axis), sea surface temperature falls away. This is the La Nina condition that affects tropical latitudes.

As surface pressure declines in high latitudes it increases strongly in the mid latitudes, 20-40 degrees of latitude encompassing the bulk of the high pressure cells that form over the Ocean all year round expanding to include cold land masses in winter.  As surface pressure increases, albedo falls away allowing more solar radiation to reach the surface of the ocean where the energy is absorbed to depth. The temperature of the surface of the sea does not reflect the extent of the energy transfer that is occurring. Over the ocean, because the energy is absorbed to depth, the surface temperature response is restrained. Where a cold current intrudes, the energy transfer can be entirely masked. 

When insolation increases over land, the surface temperature increases strongly, and the resulting atmospheric heating drives a further decline in albedo  accelerating the increase in surface temperature. This phenomenon is best illustrated by considering the evolution of temperature for the globe over a year.

The different heating rates of land and sea delivers a maximum surface temperature for the globe in July because albedo falls away with the heating of the northern land masses. The Earth is actually further from the sun in July and irradiance is 6% weaker than in January. Weak sun, warm Earth, reason is the decline in albedo.

The direct relationship between pressure and temperature brought about by a  change in albedo is illustrated below. In September surface pressure is highest in the mid latitudes and lowest in the Antarctic trough. The location takes in the east of the Pacific Ocean between Sydney and Auckland and about as much ocean again, to the east.

Wintertime polar cyclone activity in high latitudes, that determines surface pressure there, and everywhere else, changes on centennial and longer time scales. If we wish to describe a climate in terms of mean or median conditions, the computation requires at least two hundred years of data. We can see in the figures above that there is both warming and cooling, pressures increasing and decreasing within the space of seventy years. It makes no sense to refer to an anomaly with respect to the mean state for any thirty year period within the cycle of change.

This flux in surface pressure is described as the Annular Modes phenomenon, in enlightened circles, acknowledged as the prime cause of inter-annual and decadal climate variation. This is the elephant in the room of climate change that activists who beat the climate change drum, choose to ignore.

The temperature of equatorial latitudes drives the global temperature statistic because tropical latitudes constitute 36% of the total area. But in terms of understanding the Earths energy budget what happens in the tropics is simply a
mixing phenomenon. Its a smoke and mirrors trick played by the winds and the ocean.

The real action is happening in the mid latitudes. So far as high latitudes are concerned temperature is simply a function of where the wind is coming from, the variability occurring in winter, another smoke and mirrors trick.

It is in the mid latitudes that high pressure cells form, delivering cloud free skies and fine weather, the extent of this phenomenon governing the flux in the Earth’s albedo. The dynamics are well disguised because the Ocean is always in a state of movement, driven by the winds, mixing cold water into the warm.

The proportion of carbon dioxide in the air is of no account. Look at the figure below. The Southern hemisphere is no warmer in January than it was in the 1970s.  Conflicting data should trump theory. When you disrespect the data, you are practicing religion, not science. Apparently, religion is as popular as ever, just substituting the god of ecology for former gods now on the nose, due to the behaviour of their priests and disciples. A similar fate awaits the believers in the ‘carbon problem’.

What really matters is the long cycle in the Earths albedo. January is the middle of summer in the Southern Hemisphere where I live. The southern hemisphere is cooler in January at every latitude than the same latitude in July in the Northern Hemisphere. I’m not looking forward to the cooling that is coming. But I guess its all part of the rich texture of climate change. Natural climate change.

Let’s give mankind a break.

https://psl.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl

That big El Nino of 1996-7, when tropical waters hit the temperature ceiling, occurred in the trough of the most recent cooling cycle of the southern hemisphere as a whole. Notice how quickly temperature can descend.

Due to the configuration of the landmasses, warm tropical water is channeled mostly into the northern hemisphere. The Gulf Stream is illustrative. That means the Northern Hemisphere gets most of the benefit of the warmth that is taken up by the Oceans of the Southern Hemisphere. I’m for warmth. As you can see from the last graph but one, the temperature in September is limiting for plant growth. Without plants, there is no food.

Am I irritated with the climate change worriers, the United Nations Organization, the Australian Government, the carpetbaggers promoting unreliable sources of energy, academia, the ABC, the BBC, Bill Gates, Twiggy Forrest, the poor unfortunate Poms, the EEC, the Greens and the unquestioning press? You bet.

Data source: https://psl.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl

Next post: Perhaps, the evolution of the Trades and the Westerlies.

Wet summers in Australia and the incidence of La Nina

In summer 2021 tropical cyclones brought rainfall to both the west and the East coasts of Australia.

The grape vine is a Mediterranean plant that leaf’s out in summer and matures its fruit in autumn. Enhanced summer rainfall is associated with disease that attacks the leaves and fruit. To counter this, fruit may be harvested ahead of the rain. Growers are caught between a rock and a hard place.

Summer rainfall is associated with stronger surface pressure in Tahiti and lower surface pressure in Darwin and across the north of the Australian continent. This is termed the La Nina phenomenon. This paper examines the origin of that phenomenon.


Pattern of surface pressure and wind on 11/4/2021 at 1800 local time

The location of Tahiti is shown within the green circle (SLP1013mb) and that of Darwin (SLP 1008mb) in the red circle. The date is April 11 2021.  Along the coast of Western Australia, air flows from north to south bringing torrential rainfall.  A tropical cyclone moves south to merge with an intense low-pressure zone centred near the Antarctic coast.

Air pressure reflects the number of molecules in the column at a particular location. A zone of extremely low surface pressure surrounds the Antarctic continent. High pressure cells (much lighter colour) are centered on about 35S latitude, notably in the Great Australian Bight and to the east of New Zealand and over the Antarctic continent itself. The air that rises in the ‘Antarctic trough’ descends in the adjacent high-pressure cells warming as it descends, engendering a cloud free atmosphere.

On a global basis this turnover is the most persistent and vigorous because the surface pressure difference between the mid latitude highs and the Antarctic Trough is extreme. What is happening at the equator is just a sideshow to this main event. This paper will outline how the tropical sideshow depends on the dynamics in the Antarctic and the North Pacific Trough, the former active all year round, the latter for a few months in northern winter. Along the way it will be established that the agents responsible for change in weather and climate are to be found in high, not low latitudes.

ENSO

The Southern Oscillation Index is the simplest method of tracking the El Nino La Nina phenomenon. It is based on the difference in the surface pressure between Tahiti and Darwin. High index values relate to relatively high surface pressure in Tahiti and/or lower surface pressure in Darwin.

In the figure below the right-hand axis is inverted.  Superficially the temperature of the Ocean in the Eastern Pacific in the ENSO 3-4 zone appears to depend on the difference in surface pressure between Tahiti and Darwin. However, close observation indicates that in some instances the change in water temperature leads the change in pressure.

This diagram is based on the simple difference in sea level pressure between Tahiti and Darwin. It is different to the Southern Oscillation Index that is based on departures from the average pressure in each location. Later I examine the differences between these two indices in some detail.

The difference between sea level pressure between Tahiti and Darwin compared with the anomaly in the temperature of the surface of the ocean in the Nin3.4 region along the equator to the west of South America in the Pacific Ocean.
Data for the month of January. SLP from  https://psl.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl Nino 3.4 temperature data from: https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

On a global basis the Trade winds wax and wane with the Westerly winds in high southern latitudes, driving the West Wind Drift that is responsible for the anticlockwise circulation in the South Pacific. However, the wind in high latitudes is much stronger than it is in low latitudes and it peaks at a different time of the year. The circulation of water in the South Pacific Ocean moves like a swing that is attached to a post, like a Maypole, moving around the post, pushed from two extremities. The post is a high-pressure cell about which the air swings anticlockwise to all points of the compass with a greater attractor located in the south than the north. Surface pressure is much lower in the Antarctic Trough than it is at the equator. Accordingly, the surface of the Ocean is driven harder in high latitudes than in low latitudes.

The temperature of the surface of all tropical waters follows that in the Nino 3-4 region. Because the tropical latitudes have the widest circumference, the tropics amount to 40% of global surface area.  Accordingly global surface air temperature follows that in the Nino 3.4 region and the tropics generally. This evolution of surface temperature in low latitudes is due to a stop/start mixing process.

As wind intensity increases, very cold water from high latitudes is driven north towards the Galapagos Islands and westwards across the Pacific. The Antarctic Trough is the major sink generating a flow of air and water from the west to the East. So vigorous is the circulation within and above it, that the entire atmosphere rotates faster than, and in the same direction, as the Earth. But, the intensity of the circulation in the Antarctic trough changes on all time scales. The trough occupies a very large area, stretching from 40S latitude to 70S latitude. Change in atmospheric pressure in the trough manifests as a shift in atmospheric mass to other parts of the globe, modifying surface pressure relationships and the planetary winds globally.

Returning to the figure above its apparent that T_D declines between 1948 and 1978 and increases after 1978. The trend line in Nino 3.4 temperature declines with T-D until the decade of the 1960s, rises gently until the turn of the century and declines again after 2005 indicating warming in the Nino 3-4 region.

Why does the temperature of the waters in the trade wind zone not reflect the enhanced tendency for more cold water from high southern latitudes to cool the tropics as the difference between surface pressure between Tahiti and Darwin increases? The answer follows.

In the southern Hemisphere high- pressure cells dominate the expansive surface of the Southern Ocean in the mid latitudes. As surface pressure falls in the Antarctic trough it rises in the high-pressure zone in the mid latitudes where descending air is warmed by compression. Accordingly this zone tends to be cloud free. Increasing pressure widens the zone of influence of these cells directly reducing the Earths albedo, allowing more solar energy to reach the Ocean where it is absorbed to depth.

What is causing the current trend increase in the difference in surface pressure between Tahiti and Darwin? To answer this question, one needs to attend to the process of change in surface pressure. The situation is complex, and a methodical approach is required.

Blue line: Sea level pressure in Tahiti. Yellow line: Sea level pressure in Darwin. Both are average over the period 1948-2021 Dotted line: Difference between Sea level pressure in Tahiti and Darwin. Source:https://psl.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl

We see above that surface pressure in Darwin falls away more than it does in Tahiti in the summer season. For this reason the difference in surface pressure between Tahiti and Darwin is greatest in January and least in July. The reduced surface pressure in summer  indicates reduced air density associated with enhanced kinetic energy as the land mass of the Australian continent heats the atmosphere.

The atmosphere is global. Like one big bathtub. Seasonally, there is a shift of atmospheric mass from the summer to the winter hemisphere. The shift from south to north peaks in January. This is  documented in the maps below. The cooling of the Eurasian continent assists the increase in atmospheric pressure in the northern hemisphere. The generation of low pressure zones over the north Atlantic and the North Pacific Oceans retards this process. These two low pressure cells, forming over the ocean, are the northern Hemisphere equivalent of the Antarctic trough.

The location of Tahiti is indicated with a white circle.

Distribution of surface pressure in July and January. Source Japanese 45 year Reanalysis atlas

In January, surface pressure falls away in the region of Australia.  Notice the low surface pressure in the Coral sea to the east of New Guinea, an area associated with the generation of tropical cyclones, as is the zone of low surface pressure to the south of Indonesia.  

Summer rainfall across the north, the west and the East of the Australian continent is associated with the monsoonal flow and in particular the incidence of tropical cyclones. Cyclone tracks are mapped in the figure above.  Some of these cyclones, particularly on the West Coast, travel far enough to merge with low pressure systems in the Antarctic trough. It is probable that as the trough has deepened, this merging occurs more frequently.

The incidence of tropical cyclone activity increases strongly from November reflecting the evolution towards low surface pressure in summer. Peak month for cyclone activity is January. But in the next two months, while the number of cyclones falls away slightly, the number of stronger category 5 cyclones increases.

If we want to understand the evolution of the planetary winds and all forms of cyclone activity, we must understand the dynamics driving surface pressure.

Surface pressure dynamics


Average surface pressure 1948-2021 as given at https://psl.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl

The lowest surface pressure on the globe is found in Antarctica between November and January (yellow line). But on a year-round basis, the Antarctic Trough (grey line) generates the lowest surface pressure. The Antarctic Trough is where polar cyclones form.

Polar cyclones dominate the latitude band 40 to 70 degrees south. They have their genesis at jet stream altitudes where the strongest winds occur. Above the tropopause ozone reduces the number of molecules in the column of air by transferring energy to oxygen and nitrogen that has been acquired from the Earths own infrared emissions, by day and by night. In low pressure cells the upper two thirds of the atmospheric column is less dense and the tropopause, where the lapse rate of temperature with increasing altitude falls to zero, is two to three kilometers lower in elevation, than in high pressure cells. The uplift is intense, extending to the top of the atmospheric column at 1hPa or 45 kilometers in elevation, to the stratopause. The corresponding downdraft in the mid latitude high pressure cells introduces ozone into the troposphere to such an extent that at 200 hPa, the temperature of the air peaks in winter. That indicates the heating power of ozone as it is energized by infrared radiation from the Earth itself.

Relating to figure immediately above:

  • Black line: Northern hemisphere surface pressure peaks in northern winter, falling away as the air warms in summer.  
  • Dashed blue line. There is a small increase in atmospheric mass between 0-15S latitude in the winter months.
  • The difference between Tahiti (dotted green line) and Darwin (dotted blue line) is greatest in January.
  • Orange Line. This is where high pressure cells are located at 15 to 40 degrees of latitude. Atmospheric pressure builds strongly in the winter season, peaking in August. Elevated atmospheric pressure is related to cloud free skies and therefore reduced albedo. Pulses of higher atmospheric pressure (and geopotential height) are associated with an increase in surface temperature. The presence of ozone elevates the amplitude of swings in temperature above 500 hPa by comparison with the contemporaneous swings below 500 hPa and at the surface. In very cold air this strongly affects ice cloud density, opacity and reflectivity. It changes the Earth’s albedo.
  • Yellow line. There is strong increase in atmospheric pressure in Antarctica in winter, absorbing some of the movement of atmospheric mass from the northern hemisphere. High surface pressure over the Antarctic continent is associated with the descent of relatively ozone deficient, mesospheric air inside the polar vortex, deeper contrasts in air density across the vortex and enhanced polar cyclone activity. In this way, the Antarctic Trough, despite its proximity to the continent, avoids the increase in air density and surface pressure that manifests over the continent in winter.
  • Grey line. The activity of polar cyclones keeps surface pressure in the Antarctic Trough to a planetary minimum all year round.
  • Green line. Tahiti sees peak pressure in September at a time when ozone partial pressure peaks in the high latitude southern stratosphere.  

The evolution of ENSO since 1992


Source: Daily Sea Level Pressure data for Tahiti and Darwin and the SOI index: https://www.longpaddock.qld.gov.au/soi/soi-data-files/

In this diagram the 61day smoothed SOI (left axis) is compared with the simple 61day smoothed difference in surface pressure between Tahiti and Darwin (right axis). The year marked on the y axis indicates the first day of January in that year. The columns are inserted as an aid to judging the incidence of peaks and troughs in the data.

To remove the Madden Julian Oscillation from surface pressure data a 61day average is required, centred on the 30th day.

From Wikipedia: The Madden–Julian oscillation is characterized by an eastward progression of large regions of both enhanced and suppressed tropical rainfall, observed mainly over the Indian and Pacific Ocean. The anomalous rainfall is usually first evident over the western Indian Ocean and remains evident as it propagates over the very warm ocean waters of the western and central tropical Pacific. This pattern of tropical rainfall generally becomes nondescript as it moves over the primarily cooler ocean waters of the eastern Pacific but reappears when passing over the warmer waters over the Pacific Coast of Central America. The pattern may also occasionally reappear at low amplitude over the tropical Atlantic and higher amplitude over the Indian Ocean. The wet phase of enhanced convection and precipitation is followed by a dry phase where thunderstorm activity is suppressed. Each cycle lasts approximately 30–60 days. Because of this pattern, the Madden–Julian oscillation is also known as the 30- to 60-day oscillation, 30- to 60-day wave, or intraseasonal oscillation.

Relating to figure above

  • T-D (orange) is the simple difference between atmospheric pressure between Tahiti and Darwin). This statistic is rarely negative, unlike the SOI (Blue). The default arrangement is for winds to blow east to west driving cold surface waters westwards. This relates to a positive value for T-D except briefly, in the winter season, manifesting in only 9 of the 29 winters.
  • T-D exhibits an annual cycle, not always evident in the SOI, with a consistent peak in December-January-February. Because the SOI (left axis) is computed to reveal anomalies in relation to the average, this peak is suppressed, a January peak occurring only when the anomaly is abnormally large. Another difficulty with this statistical treatment (departure from the average) is that trends are distorted as the average changes. The average is always changing because the climate of the Earth changes over time naturally. ENSO has been present for thousands of years.
  • The peak in T-D rarely strays from early January.
  • The timing of the trough in T-D, that occurs in the winter season, is irregular.
  • The year-to-year variation in T-D in January is much larger than the variation in the trough in winter. This points towards a dominant Northern Hemisphere influence driving change in surface pressure in January because shifts of atmospheric mass primarily emanate from the winter hemisphere. In the winter season the Antarctic trough dominates.
  • The SOI is noisy by comparison with T-D. It conceals rather than reveals the surface pressure dynamic that drives the winds.
  • Because T-D is positive almost all the time, the circulation of the Pacific Ocean in the Southern Hemisphere is always anti-clockwise. The warmest water is always in the Western Pacific located in South East Asia and the Indonesian archipelago. This is the case even when the trade winds falter, because the trades reverse for only a tiny fraction of the time and it is the constant north westerlies that are the dominant driver of the circulation of the waters of the Pacific Ocean. There are parts of the Pacific Ocean that have not warmed with the tropics. In fact they are cooler today than when records began.
  • Negative T-D implies a reversal of the trades to blow West to East. This is the El Nino condition when the centre of convection moves from the western to the Eastern Pacific. This is facilitated by the eastward movement of local centres of convection that originate in the warm waters of the Indian Ocean documented as the Madden Julian Oscillation that has a frequency of 30-60 days. In addition, the Earth’s atmosphere moves from West to East, rotating faster than the Earth itself with the speed of travel increasing with latitude. This opposes the east to west movement of the trade winds. The MJ oscillation and the generalized movement of the atmosphere to the east, tends to move the centre of convection over cooler waters in the eastern Pacific regardless of the T-D surface pressure differential. Convection, once started, is self-reinforcing via the release of latent heat. To the extent that the movement of cold surface waters to the west is slowed as the Trades and the Westerlies weaken, the waters of the Eastern Pacific will warm up, assisting the movement of the centre of convection to the east.
  • There is a 10-13year long wave in T-D.  The peaks in T-D are punctuated by anomalous deep troughs.  These anomalous troughs occurred in (1997, 1998) and (2009,2010), by far and away the years with the strongest El Nino tendency. The abrupt reversal from cold to warm is associated with a build up of warmer waters in the mid latitudes that spill into the tropics to the exclusion of colder waters from higher latitudes. Energy gain in the mid latitudes relates to elevated surface pressure there, driven by low surface pressure in the Antarctic trough. So far as the ocean is concerned, energy is absorbed to depth and its distribution is affected by mixing processes. It follows as a matter of logic that one cannot assume that an average of global surface temperature actually reflects the process of energy acquisition and emission by the Earth as a whole. To assess the energy balance, one should endeavour to measure the energy stored in the atmosphere and in the ocean, at least to the depth of the ocean that light penetrates. To speak of the hottest year since records began, while it adequately describes surface conditions tells us nothing about the underlying process of energy acquisition and emission.
  • The trough in the 10-12year long wave in T-D rarely manifests negative values. But this occurred notably in (1993,1994), (2002,2004,2006) and 2015.
  • Any weakness in the Antarctic trough will manifest as a slowing in the anticlockwise movement of the Pacific Ocean in the southern hemisphere. Weakness in the trough is associated with a decline in atmospheric pressure in the high-pressure cells of the mid latitudes and a consequent increase in cloud cover reducing the uptake of solar energy in the mid latitudes. It follows that the energy balance in the climate system will turn to the negative (emission exceeding acquisition) when surface pressure in the Antarctic trough begins to increase.
  • The surface temperature dynamic was much affected by a marked increase in the temperature of the stratosphere in the late 1970s, a reflection of its ozone content, the origin being a relative collapse in the intake of mesospheric air due to a fall in atmospheric pressure over the Antarctic continent at that time. The temperature change propagated globally affecting temperatures in the upper troposphere, reducing the Earths albedo.

Dynamics affecting the evolution of the system.

The data in the figure immediately above suggests that the annual cycle in the differential pressure between Tahiti and Darwin is part of a longer 10-12year cycle, cause unknown.

The annual cycle involves change in cloud cover related to the central pressure within and the change in the area occupied by high pressure cells.

The strongest zone of uplift on the planet is not located at the equator. It is located on the margins of Antarctica. The change in cloud cover in the mid latitudes is directly related to the vorticity and volume of air uplifted within the Antarctic trough. This should focus our attention away from the Hadley cell, that is characterized by weak and fluctuating trade winds towards high latitudes.

Evolution of surface pressure in Tahiti and Darwin by month of year

Evolution of sea level pressure in Tahiti and Darwin for each month of the year since 1948
  • Surface pressure has increased most strongly in September pointing towards enhanced cyclone activity in the Antarctic Trough.
  • Trends in sea level pressure in Tahiti and Darwin tends to converge in the middle of the period but with a secular increase in all months over time.
  • Between November and March, the amplitude of the individual swings in surface pressure increases.
  • The T-D Negative status (westerly winds) manifests most strongly in January, February and March.
  • From October through to March the variability in Darwin is generally greater than in Tahiti.
  • Surface pressure in Darwin and Tahiti tend to be anti-correlated at all times of the year, but not strictly so. This lack of strict correlation indicates that the migration of the zone of convection is influenced by conditions unrelated to the process of convection itself. This invalidates the notion that the ENSO phenomenon is solely due to an interaction between the atmosphere and the ocean in tropical waters.
  • Year to year volatility is strongest in September-October, falls away in November then ramping up in December-March.
  • In January the thirty years between 1969 and 1999 had the greatest potential for pressure reversals between Tahiti and Darwin.
  • From 1980 to 1999 conditions in March favoured El Nino.

The origins of shifts in atmospheric mass

The figure above shows the evolution of the Antarctic and the Pacific troughs over time, its relative depression in relation to the North Pacific trough and the competition for influence on southern hemisphere atmospheric pressure from the North Pacific Trough in December, January, and February. To be more complete this analysis should be extended to compare the evolution of surface pressure in North Pacific, to that in the North Atlantic perhaps a subject for another day.

We see in the figure above that, in January, the shifts in atmospheric mass consequent on changes in the intensity of the North Pacific trough are much more substantial than those emanating from the Antarctic Trough. In the main, a depression in pressure in the Pacific trough coincides with an increase in surface pressure in the Antarctic Trough and vice versa. However, its not a simple case of atmospheric exchange within a closed system. The red arrows mark occasions when both troughs move in the same direction emanating from a global change in the partial pressure of ozone in the upper air or perhaps an electromagnetic jerk affecting the rotation of the atmosphere. Either way, the agent of change is external to the Earth, not the product of an internally generated change within a closed climate system. This system is open to external influences. If we don’t acknowledge this dynamic that affects the planetary winds, the Earths Albedo and ENSO, we have our heads buried in the sand. When I survey the climate science literature and the work of the United Nations all I see is bums in the air.

Conclusion

Due to the complexity of the origins of shifts in atmospheric mass from the high-pressure troughs in both hemispheres, the fact that the troughs vary in their influence according to the month of the year and according to external influences that are currently unrecognized, and currently unpredictable, it is not possible to anticipate the likely evolution of climate from year to year or in the decade to come. Modelers should acknowledge this and back off.

However, given that cloud cover in the mid latitudes is undoubtedly a function of the evolution of the high latitude troughs, we can say that, when the troughs weaken, the beneficial warming trend that commenced in the late 1970s will reverse.

It is well to remember that the temperature of the Earth peaks in July when, due to orbital considerations, solar radiation is 6% weaker than in January. Global cloud cover reaches its minimum in July, its maximum in January. This demonstrates the importance of albedo in determining how much solar energy reaches the ocean, the only medium that can absorb solar energy to depth and retain it for long periods of time. The atmosphere is incapable of retaining energy. Any energy gain is strictly temporary, swiftly countered by convection and decompressive cooling with a compensatory compression in the mid latitudes where most of the radiative energy emitted by the Earth system emanates from high altitudes. Radiation theorists need to acknowledge this geometry and back off.

It is stupid to suggest that there is ‘a climate or any other sort of emergency’ when something bad is expected to happen if we as humans are powerless to influence the course of events.

It’s comforting to remember that warming has been highly beneficial. The bulk of the globe is too cold for comfort, especially in winter. This is what the green tremolos need to fully absorb, and admit. Then back off for the good of humanity.

As for the grapes, the great years have dry summers, frequently associated with an upswing in the solar cycle like the one that is now underway, albeit weakly.