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.