I want to thank the resourceful Zoe Phin for the data presented below. You can download the data here. If that doesn’t work try here:

This figure shows the average atmospheric albedo by month of year from March in the year 2000 through to March 2021. Atmospheric albedo is the extent to which solar radiation is reflected by particles in the atmosphere back to space where they are sensed by an instrument on a satellite. The data indicates that more than 30% of the energy of the sun fails to reach the surface of the Earth in December while in August only 28% is lost to space.

Question 1. What are the particles in the atmosphere that could be responsible for reflection of solar radiation and where are they likely to be located?

Question 2. What’s the origin of the anomalous bump in the descent of albedo between February and July?

Question 3. The Earth is closest to the Sun in January and furthest away in July. This makes for a 6% difference in the intensity of solar radiation. What wins out do you think. Would a 3% increase in the proportion of radiation reaching the surface due to less reflection in July compensate for a 6% reduction in the intensity of solar radiation at that time? The Earth as a whole is about 2.5 degrees warmer in one or the other month. Which month? July or January? Why?

Question 4. How does this dynamic relate to Greenhouse theory?

The diagram above traces the evolution of albedo by month over the last two decades.

Question 5 Which month exhibits the biggest short and long term variability?

Question 6. What’s the average interval between peaks in that month?

Question 7. Why is the evolution of albedo in January a mirror image of that in October?

Question 8. Why is September a consistent 91-92% of the figure in November and the evolution of albedo so different in these two months by comparison with adjacent months?

Question 9. Is September setting up for October, November and December or does its pattern indicate an anomalous jerk away from a prevailing pattern? If the latter, what could be causing that jerk?

Question 10. Is this change in albedo, that is different from month to month, likely to be part of the reason for variations in the temperature in a particular season or are there other things that come into play. If so, what are they?

Question 11. Could anything in the Earth system be responsible for the change in albedo that we see here? Is the Earth an Island unto itself or could its atmosphere be influenced by circumstances external to the Earth considering the atmosphere as part of the Earth system? If influenced from the outside environment what part of the Earth is likely to be impacted and in which season?

The diagram above traces the evolution of departures from the monthly average atmospheric albedo and average monthly global temperature for the period 2000 through to 2021. Temperature data is from here

Please note that Albedo is on the right hand axis which is inverted. So, an upward movement in the albedo trace represents a decline in the amount of radiation that reaches the surface of the Earth.

Question 12. Is there a relationship between the two? Could the change in albedo be related to the change in temperature in terms of causation? Is there any factor that could reverse the relationship in the short term, i.e temperature rising as albedo increases and vice versa?

Question 13. The temperature curve departs from the albedo curve strongly on at least two occasions. What could be responsible?

Question 14. In what latitude, hemisphere and location is this variation in albedo likely to be most evident?

Feel free to speculate. Don’t feel bad if there are some questions that simply stump you. Just pass them by. I’m going to send a bottle of very nice red wine to the person that, in my opinion, makes the most sense.

12 thoughts on “Questions

  1. Erl, I am not really in to the question and answer thing, but you may be interested in this chart which basically agrees with Zoes and your Albedo data.
    This Chart comes fromClamate4you and is self explanatary.

    He has many charts of cloud and albedo amongst others.
    it is a place of great data gathering.


    1. Great. I am familiar with Ole Humlum’s great work on climate. I am on his newsletter list. I like the historical articles that he finishes up with.


  2. I don’t think I’ve got much chance of winning that “bottle of very nice red wine”, but that’s okay… I don’t drink wine.

    A lot of your questions are not all that important. Drink half a bottle of bundy and you’ll see that I’m right.

    Seriously, our planet’s climate is entirely solar powered and the whole thing self regulates. Albedo changes with water vapor, which changes with temperature. Everything has limits…. which is why the planet has never experienced runaway warming, and why it never will. Albedo is a small piece of a very large puzzle… and it’s very difficult to analyze albedo because it’s driven, it’s not a driver.


    1. I’ll give it some time and see what happens before I deliver my own views on the matter. But, in short, mid latitude surface pressure is highly variable and with it, cloud cover. So sea surface temperature rises with surface pressure in that zone. Mid latitude surface pressure in the southern hemisphere has been rising for seventy years. It’s unfortunate we only have 20 years of data for albedo. The oceans transport energy from the southern to the northern hemisphere. Looks to me as the atmospheric window of low albedo in the mid latitudes of the southern hemisphere opens and closes on very long time scales.


      1. “It’s unfortunate we only have 20 years of data for albedo.”

        And there is half the problem. 20 years of data isn’t enough to even try to filter out noise. The other half of the problem is that the temperature time series isn’t fit for purpose… it hasn’t been since they brought out the pause-buster version. You’re trying to correlate a very short albedo time series with a virtually worthless temperature time series. Good luck with that.

        Sorry to be so blunt, but etiquette is not my forte.


      2. The only temperature series we have that gives data for the entire atmosphere at all latitudes and pressure levels is the reanalysis data.
        Fortunately, the changes that are wrought by nature affect particular latitudes, at particular pressure levels, and are gross in magnitude. So, the signal is not affected by the margins of error or methodology or the changes that might be made with intent to deceive. So, I cannot agree with you on that count.

        Just came across this which I think summarizes the situation very well.

        “Many humans believe that they make decisions on data and logic.”
        “Because of this and their friends they think most humans do.”
        “Actually most humans make decisions on emotion and what their friends think.”

        I do the same but with things that really matter I am one of those few who look very carefully at the available data.


    1. Thanks AC, an excellent article. I have left the following comment:
      Undoubtedly cloud cover is related to insolation received at the surface. I have taken the Ceres data produced by Zoe and looked at the variability by month presenting the analysis here:

      I’m inviting comment before I offer the interpretation.

      I agree with this summary: All of these forcing magnitudes easily dwarf the impact from CO2 concentration increases in cloud-free skies and affirm “clouds may be the most important parameter controlling the radiation budget, and, hence, the Earth climate” (Sfîcă et al., 2021).

      Basic reason is that clouds don’t warm via back radiation. You can measure enhanced back radiation in a cloudy atmosphere. Its due to the fact that the air comes from the equator, its warm and moist. But albedo is seasonally least in August when solar radiation is 6% weaker than in January and the globe is 2.5 degrees warmer than in January. Global cloud cover is least in August due to the heating of the atmosphere by the continents of the northern hemisphere. Global cloud cover rises steeply to its peak in December and it is in this interval that the greatest variability in albedo is seen. This affects the energy intake in the atmospheric windows over high pressure cells in the southern hemisphere. The Southern hemisphere absorbs more energy than it emits, the difference being transported to the North in the Oceans.

      The atmospheric windows are surface pressure dependent. Surface pressure is dependent on polar cyclone activity in the Circumpolar Antarctic Trough and also, the Aleutian Low and the Icelandic Low that come into action in October.


  3. Of the rocky planets, the one with easily the highest albedo (0.75 to Earth’s 0.3) also has by far the highest surface temperature, i.e. Venus. Some will cry ‘greenhouse’ but look at the surface pressure, 92 bar to Earth’s 1 bar. What would Earth’s surface temperature be with that kind of atmospheric pressure?


  4. Hi Oldbrew, very much appreciate your visit to this lonely place.
    I don’t have a definitive answer. Here are some thoughts off the top of my head, in response to your question.
    If Venus were as remote as Pluto and the watts per square metre of solar insolation falling on the planet commensurately reduced, I don’t think the higher surface pressure would necessarily make it warmer unless the gases are dead-end stationary, as they are in a woolen blanket.
    The highest surface pressure on Earth is experienced in Antarctica in winter. It used to be a lot higher than it is today but at that time Antarctica was colder in winter.
    On Earth, the mid latitudes of the Southern Hemisphere have higher surface pressure but that’s due to the fact that air that is uplifted at the polar front and at the equator has to return to the surface somewhere. These latitudes have warmed strongly but its not due to pressure but reducing albedo. The kinetic energy that is gained due to compression in the descent never reaches the surface. Its continuously radiated to space through a local atmosphere that is dry and cloudless.
    At latitudes greater than about 30° on Earth watts per metre emitted as radiation exceeds watts per square metre absorbed from solar radiation. So, this creates a source sink relationship with a transfer of energy from the tropical side to the higher latitude side. The transferred energy never returns. It is very efficiently radiated to space so that a situation occurs where the surface is cooler than the air that travels above it, and its always travelling one way or the other. The local temperature depends on where the air is coming from.
    The atmosphere on Earth is exceedingly thin with 90% of its mass within 10,000 metres of the surface. To have a surface pressure as great as that on Venus I imagine that there are many more molecules heaped up and perhaps they are individually heavier. I imagine that the atmosphere there is deeper.
    Any gaseous medium retains energy poorly because it sets up convectional currents when there is uneven heating. Is there a difference in temperature between Venus’s equator and its poles?
    What’s the temperature on the night-side. How long is a Venusian day? What’s the tilt on its axis of rotation? Temperature in summer and winter? What’s the degree of ellipticity in its orbit around the sun? What do we know about the lapse rate with altitude?
    Is there an absorber of long wave energy in the Venusian atmosphere that can pick up energy at the wave lengths emitted lower down, transfer energy to adjacent molecules, raising their temperature in the same way as ozone does this on Earth enabling the temperature of the air at the stratopause over Antarctica to reach or exceed that at the surface in the tropics? That’s not going to raise temperature at the surface unless the atmosphere is static (dead rigid, as in a solid) but it will reduce the lapse rate and affect local temperature at every altitude.
    The atmospheric blanket around Venus must be a lot deeper and it could be less efficient as a transmitter of energy away from the planet but in general, a vacuum is necessary of one wants to conserve the energy that accumulates in a solid body.
    I reckon, I would need to know a lot more about Venus to be comfortable in making assertions about why things are as they are.
    Generalizing, temperature at any place is a function of the balance between incoming and outgoing energy. The warmest latitudes on Earth don’t radiate as much energy to space as comes in via space relying on movement of air and water to transfer the difference to locations where the source/sink relationship is reversed. I’m starting to think of the arrangements on Earth are quite similar to what we have in a domestic refrigerator.
    In that respect, do you reckon a refrigerator would be more or less efficient if we flooded the internal space with CO2, Nitrogen or Argon by comparison with plain old air? What about if we put the fridge on its back so that the cold air didn’t spill out of it every time we opened the door?


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