Guest Post by Willis Eschenbach
Inspired by Richard Keen’s interesting WUWT post on using eclipses to determine the clarity of the atmosphere, I went to the website of the Hawaiian Mauna Loa Observatory. They have some very fascinating datasets. One of them is a measurement of direct solar radiation, minute by minute, since about 1980.
I thought that I could use that dataset to determine the clarity of the atmosphere by looking at the maximum downwelling solar energy on a month by month basis. I’ve described my method of extracting the maximum solar energy from the minute by minute data in the appendix for those interested.
Now, according to Dr. Keen, the air is cleaner now than it’s been in a while:
“Based on the color and brightness of recent eclipses, we can say that Earth’s stratosphere is as clear as it has been in decades. There are very few volcanic aerosols up there,” he explains.
Now, the Mauna Loa Observatory (“MLO”) is a great place for taking measurements of a variety of things. Located at an elevation of 11,135 feet (3,394 m), it is above the low-lying clouds (although not all clouds, it gets snow …).
So what it is measuring is basically what Dr. Keen is measuring, the clarity of the upper part of the troposphere and the stratosphere above that. Any aerosols in the stratosphere will cut down on the maximum amount of sunshine that makes it through. With that as prologue, here is the record of maximum sunlight at MLO.
Figure 1. Maximum sunshine, month by month, at MLO. Vertical colored bars show a 2-year period starting at the eruption dates of the two volcanos, El Chichon and Pinatubo. Values are in watts/metre squared (W/m2).
To start with, we can see that whether Dr. Keen is right on a global basis about the atmosphere being as clear as it has been in decades, it is certainly not true at MLO. Other than after the volcanic eruptions, the clarity of the atmosphere is unchanged since 1980.
However, I had a deeper purpose. My theory, as I have discussed many times, is that the clouds respond to changes in total forcing in such a manner as to oppose them. Given that, I wondered what I could determine about what happens at MLO after big volcanic eruptions of the type shown in Figure 1.
To investigate this question, I looked at the minute by minute maximum solar energy and compared it to the average solar energy. I divided the dataset shown above into two parts—the two 2-year volcanic sections shown as vertical colored bars in Figure 1, and the rest of the data. Figure 2 shows just the part of the dataset that does not contain the eruptions. It lays out both the maximum solar energy and the average solar energy after losses due mostly to clouds.
Figure 2. Average minute-by-minute evolution of the daily maximum and average solar radiation at MLO.
Fresh powder snow in the Hawaiian Islands, what’s not to like? But I digress …
In Figure 2, you can see how the clouds start building up in the morning. By one in the afternoon, they are knocking the instantaneous solar radiation down to about 700 W/m2 from the morning peak about 1,100 W/m2
Now, that’s interesting in itself … but what is more interesting is what happens after a volcanic eruption. Figure three shows the same data as in Figure 2, with the addition of the maximum and average solar energy during the two-year period after each of the volcanic eruptions.
Figure 3. As in Figure 2, with the addition of the maximum and average solar energy values for the two-year period following the eruptions of El Chichon (orange) and Pinatubo (yellow).
For me, the best part of doing scientific research is when I get surprised by my first view of the data. In this case what was surprising was how very similar the results of the two volcanoes were. Despite the difference of the size and location of the two eruptions, both the maximums and the averages of solar radiation after the two eruptions are very nearly identical … go figure. It makes me think that over a certain point, the stratosphere somehow maxes out and doesn’t cut out any more light.
As expected, the maximum energy making it through the upper atmosphere is significantly lower during the volcanic periods. And the averages were smaller as well. The average downwelling total solar radiation (direct and diffuse) was about 24.5 w/m2 less during the volcanic periods than when there were no volcanos.
So … how did my theory fare? My theory predicts that during the volcanic periods, the clouds would rearrange in order to cut out less sunshine, opposing the effects of the volcanic aerosols.
And in fact, this is exactly what they did.
During the time when there were eruptions, the clouds prevented the period from about 11AM to about 4 PM from decreasing at all … in fact, around 1PM the solar input during the volcanic periods was actually larger than during the non-volcano periods.
If the same percentage of sunlight had been cut out by the clouds during the volcanic periods as when there were no volcanos, instead of an observed loss of 24.5 W/m2, we would have expected a loss of 31.3 W/m2. This means that the rearrangement of the clouds increased downwelling solar radiation by about seven W/m2 …
However, despite the countervailing action of the clouds, there was still a significant loss of radiation, about twenty-five watts per square metre (W/m2). How much is 25 W/m2? The IPCC says that a doubling of CO2 will cause an increase of 3.7 W/m2. So to get the 25 W/m2 change seen during the eruptions, the CO2 would have to go from the current 400 ppmv to 43,250 ppmv …
So what difference did the loss of 25 W/m2 of sunshine make to the local temperatures? Now that’s an interesting question, and one which we can answer. The MLO also has taken temperature readings over that period, so we can compare apples to apples. Here is the result:
Curious, huh? On average the MLO site received a full 25 W/m2 less solar radiation for an entire two years, and the temperature was unchanged …
I thought, well, maybe I’m reading things wrong. So I went and got some other temperature records from the Hawaiian Islands, because since MLO received less solar energy, all of Hawaii would have received less solar energy … here are the records that cover the times in question. Some don’t cover all of the volcanic periods, but there’s enough data to see if the eruptions actually affected the temperature.
I looked at other Hawaiian Island stations from the nearest to MLO to the furthest. Here’s the nearest station, Hilo, on the same island as MLO. It doesn’t contain the entire El Chichon record, but there’s enough there to see it didn’t cool down during the first year after the eruption. And there was obviously no effect from Pinatubo.
Next, here’s the record from Molokai, a couple of islands over from MLO … no effect from either eruption on Molokai Temperatures.
Next, Barber’s point on Oahu … same story. No effect.
And finally, at the far end of the Hawaiian Island chain from MLO, here’s Lihue, on Kauaii. Like the other stations, Lihue apparently didn’t get the memo about the 25 W/m2 reduction in solar radiation …
So … why was there no reduction in the temperatures anywhere in the islands from that large a change in forcing? That one is easy to answer …
I don’t know, and I doubt if anyone knows.
After all, in mainstream climate science it is accepted as an article of faith that the reduction in solar energy will and must cause a fall in temperatures … I’m the only person I know of who is heretical enough to seriously question this dogma. See, e.g. my posts called “Volcanic Disruptions” and “Missing The Missing Summer“.
My theory is that the climate system is not like a pool table, where you can calculate from the force applied to the cueball precisely how the other balls will move. Instead of being fixed, the climate system responds to any change in conditions in a number of ways, both seen and unseen. And following both the Constructal Law and Le Chatelier’s Principle, the changes all tend to restore the status quo ante.
But hey, that’s just my explanation why neither Pinatubo nor El Chichon affected Hawaiian temperatures. If someone else has a better idea why a drop in the amount of solar radiation reaching the ground of some 25 W/m2 for two years hasn’t affected the local temperatures, I’m all ears.
[UPDATE] Commenters asked about something I’d considered, whether it was a change in the wind speed that had affected the temperature. It appears that the answer is no.
The difference between eruptions and no eruptions is well within the uncertainty of the data.
A foggy morning here. We’re six miles from the coast, and despite how far it is, the sea breeze brings me the distant sound of the surf and the foghorn on the breakwater … this is assuredly the most audacious and finest planet I’ve ever lived on.
Best wishes to everyone, my thanks to Richard Keen for setting off this train of thought,
w.
AS ALWAYS: I ask that when you comment, you quote the exact words you are referring to. This lets all of us be crystal clear about just who and what you are talking about. Can’t tell you how tired I am of comments that start with “You are …” when I have no clue who the “You” in the sentence refers to. Makes me want to tell the kids to get off my lawn …
DATA: The Hawaii temperatures are from GISS.
The MLO data is available by FTP from here. Big files, because the data is taken every minute.
The MLO meteorological data (temperature, wind, pressure, etc.) is available by FTP from here. There is both minute and hourly data, I used the hourly data for the graph above.
There is also downwelling longwave data there … but unfortunately, it doesn’t start until 1994 … rats …
METHODS: The MLO solar radiation data is in two versions in different years—every three minutes in the early version and every ten minutes more recently. I first converted them all to ten-minute intervals, in part to reduce dataset size.
There are a couple of datasets of interest, the direct solar and the diffuse solar values.
For each month, I calculated the maximum and the average direct solar values for each ten-minute interval. Then, I took the time of the maximum direct solar, and I extracted the diffuse solar for that instant. That gave me the maximum total direct solar, plus the corresponding diffuse solar values.
Once I had the direct and diffuse maximum and average values I divided the datasets into volcano and no volcano sections by removing the data from the date of each eruption and for two years afterward. This let me compare average values for when there were and were not eruptions and their aftermath.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Really enjoy reading the willis posts.
Many thanks.
Really enjoy reading the willis posts.
Many thanks.
Interesting post. I would have expected a clear effect on temperature from major eruptions, and there wasn’t one.
Tom Halla:
On the other hand, Wordfortrees.org plots of average anomalous global temperatures for both GISS and Hadcrut4 clearly show a temperature decrease of about o.2 deg C. for both volcanoes.
So why not over Hawaiii?
Hawaii are islands in a warm ocean. It takes a long time for an ocean to cool of significantly.
Exactly. We’re talking about Islands here far from any continental land mass with constantly changing generally warm waters around them. UAH shows noticeable drops in global temperature for the period after Pinatubo. So it would seem to me that SSTs around the islands would have a lot to do with the temps being recorded there.
It would be really useful to have similar station récords from Kilimanjaro in Tanzania and Pico Bolivar in Venezuela
I don’t believe that an ocean takes two years to cool off. Second, what happened to those 25 W/m2? It probably heated the atmosphere before it got a chance to heat the surface.
Burl,
That’s within the margin of error for the instruments being used, so a 0.2C difference is not significant.
Because there is no real average anomalous global temperature. It is made up.
” GISS and Hadcrut4 clearly show a temperature decrease of about o.2 deg C. for both volcanoes”
It’s basically the noise that gets averaged out over many stations. A variation of, say, 0.2°C is very obvious in the global average, where year-year variations of 0.1°C (as in 2016) stand out. But a single site like Hilo has year-year variations of 1°C or more.
The noise cannot get averaged out over many stations – unless you can somehow prove that the noise is identical at each station and attach time of measurement.
Measuring the same thing many times is not the same as measuring many different things.
Hi Willis, is there any data available about incoming solar energy near the base of Mauna Loa, near sea level?
If clouds are responding to counter change to incoming solar radiation, the response should be more pronounced at sea level than at Mauna Loa which is above much of the cloud cover.
For what its worth I think you’ve made the case – the lack of temperature response is a good indication that some feedback is damping the temperature response to change in forcing. But it would be interesting to see how much low level clouds contribute to this response.
Eric, I don’t know of any such sea level data, sadly … lack of data is one of the biggest frustrations of working in climate science.
w.
That doesn’t seem to stop a lot of “climate scientists”. When you only have a few actual reporting stations in large areas of the globe like the arctic or central Africa, you just make it up (although they call it modeling).
Really, Just take the temperature of San Diego and propagate it into a 5000K x 5000K grid cell then project it over Hawaii. Isn’t that what Climate Science is all about??
Eric,
The temperature data from Molokai, Oahu, and Kauai are almost certainly at lower elevations than MLO, and they appear (to me) to show lowered temperatures during the El Chichon event;
Willis – great article! Thanks!
However in the paragraph beginning “However, despite the countervailing…” just above unmarked Fig4, you mention “eclipses” when I guess you actually meant “eruptions”.
Thanks, Phil, fixed.
w.
My friend’s dear old mom, while discussing St. Helens, mentioned past major erections when she meant eruptions.
(At least I hope she meant eruptions.)
@max Photon
(At least I hope she meant eruptions.)
*SNIP* Many would count that as racist – MOD
Is there a seasonal signal? UK sunshine shows a big change in winter sunshine, not so much in summer.
Is there a change in wavelength? UV penetrates deeper into ocean.
Sunshine, Mauna Loa is at about 19°N, so it’s in the tropics where summer and winter are not that different. As to the wavelengths, I don’t know of any spectrally resolved data. However, I assume that there would be a change in frequency from the presence of the volcanic aerosols.
w.
May I suggest checking the prevailing pressure systems.
I suspect more high pressure systems developed during the 2 year eruption phase.
Thank you, Mr. E, you have a knack for writing with clarity
One question came to my mind. The Hawaiian islands are surrounded by warm
water. Heat spontaneously always flows towards cold. To maintain the “equilibrium” could the ocean have released heat to, perhaps, counter any potential cooling from volcanic aresols.
Thanks for the kind words, John. I don’t know how much effect the ocean has on the situation. As I said in the head post … I don’t know …
w.
Willis, as we all know, water is much slower to cool than the atmosphere, so it is understandable that Hawaii would not see much change in temperature over just 2 years. The Pacific Ocean is something of a near neighbour to Hawaii, after all.
Now a site in the central parts of North America, Europe, or Asia would very possibly show a different response in the same time-frame..
Thanks, Ray. In fact, the ocean warms and cools by quite a bit, several degrees per month. I just ran the numbers. In the Hawaiian waters, over the course of six months the average surface solar input changes by about 100 W/m2 and the ocean temperature changes by about 16°C … that’s about 4°C for 25W/m2 in six months.
Given that we had a 25 W/m2 difference that lasted for two years, a clear dip in the ocean temperature greater than 4°C should have occurred.
w.
Willis, Is this an indication of local rather than global impact?
We don’t know the frequency range of the missing 25 W^2m. I remember the vivid pink twilight skyglow scatter in Jan thru April 1992, a beautiful sight. I expect that’s the bulk of the missing photons in band.
16? Honolulu is only varying by 3.
https://www.seatemperature.org/north-america/united-states/honolulu.htm
Given your findings that the clarity of the atmosphere is unchanged since 1980 (barring the eruptions) what might be causing Dr Keen’s observations of apparent clearing over time?
I suspect Dr. Keene might be comparing post-Pinatubo clarity to pre-El Chichon clarity … but even that seems doubtful given Figure 1.
w.
To clarify, so to speak, the point of my study is that the average aerosols since 1995 are less than the average for the 15 years before, i.e., the stratosphere is overall more clear.
The quote from the Spaceweather article:
http://spaceweather.com/archive.php?view=1&day=24&month=05&year=2018
“Based on the color and brightness of recent eclipses, we can say that Earth’s stratosphere is as clear as it has been in decades. There are very few volcanic aerosols up there”
does not say it’s *clearer* now than at some times prior to el Chichon and Pinatubo.
The colorful poster does say:
“… the global volcanic AOD remains at very low levels. A 22+ year period of a relatively clear stratosphere therefore continues, and is the longest such stretch since 1837- 1862. The stratospheric impacts of several climatically insignificant volcanoes during 1996-2018 are identified. There is no trend in AOD over this period, ruling out volcanoes as a contributor to the stable global temperatures during 1998-2015. Compared to the volcanically active period 1980-1995 (el Chichon and Pinatubo), the clear stratosphere since 1995 has contributed an increase of radiative climate forcing equal to that due to increasing greenhouse gases.”
There is no contradiction between my eclipse data and the MLO data, and the big thing in both observed data sets is the ongoing 22+ year stretch without major volcanic events.
So w’s statement that “Other than after the volcanic eruptions, the clarity of the atmosphere is unchanged since 1980” misses the entire point of my article, which is about those volcanic eruptions (and the subsequent lack thereof).
Richard Keen May 29, 2018 at 11:31 pm
Richard, thanks for the comment. Of course the average aerosols are less since 1995 than in the previous 15 years, when El Chichon and Pinatubo erupted.
In any case, the year 1980, before either El Chichon or Pinatubo, was as clear as the recent years.
Finally, after both Pinatubo and El Chichon, the stratospheric aerosols were completely gone after a mere two years … so I find it difficult to believe that there was something that lasted for “decades” prior to those much larger eruptions.
Next, you say:
There is absolutely no sign in the MLO record of the eruptions that you identified as having a “stratospheric impact”. Nor is there any sign of them in the UAH MSU Stratospheric Temperature record, which like the MLO record sensitively recorded the El Chichon and Pinatubo eruptions.
I see nothing but random fluctuations there, nothing of note.
Best regards,
w.
Mr Eschenbach, I think that there may be a couple of points about whether or not the Volcanoes have an effect.
Fiirst of all Soufriere appears to have continued a downward trend.
Whereas Ulawan on it’s own had no effect but when Reventador is added temps dropped.
Like Soufriere, Rabaul also continued a downward trend.
Puyene appears to have had no effect whereas Calbuco does.
So could it be a combination of the “Content” of erupted material, the height that the material gains, the prevailing winds and therefore how quickly and how far the material gets spread?
I also do not see Eyjafjallajökull on your chart, it certainly affected Europe, but I am not sure about world wide.
It takes a particularly short high-energy vertically-directed explosive impulse to project the particles and gases above the top of the troposphere. The other explosive eruptions, although very impressive, were weaker and achieved much lower altitudes.
@A C Osborn:
You seem to be putting the cart before the horse by claiming that volcanic eruptions “cause” both heating and cooling without advancing empirical data to support the claim that the characteristics of the eruptions might be the root cause. We await your actual analysis with interest.
Please point out where I mention any kind of “warming”.
I’m sorry, mate, but I think you must have confused Farenheit when you said Hawaii water cools 16°C.
No way does it cool that much in winter. Unless it is due to cold fresh water entering in the rainy season at the sight. Temperatures would range from 30-31°C to 21-24°C. People surf in boardshorts all year. There is no cold current in winter.
Summer is hotter at 19°North than it is ever on the equator. The sun is just about directly overhead for about 50 consecutive days, twice as long as it is when passing over the equator. On the 27th of May the sun is a week away from being overhead. June 3rd it is directly overhead. June 20th it is 4.5° off being overhead. 17 days later it is directly overhead again. A week later it is 2° from being overhead. It is still mid summer.
Can you see that in the readings? Does that shine light on anything?
Like you, I don’t know. Maybe Tradewinds off the warm water keeps the air warm. Also, a lot of latent heat gets emitted when the moist surface air gets blown up the mountain into the cold where it condenses. Whatever it is, it is probably local, as a point of where to start looking, because the world did cool due to the volcanoes.
Hmm.. I guess I have accepted the dogma that a major eruption is followed by 1 or more cool years. I need to go back and look at those studies again.
Now I am wondering if Hawaii is insulated from such temperature dips due to the ocean surrounding it, acting as a temperature change buffer – seems reasonable. Or are the temperature dips an artifact of how they calculate the global average? For example, if a volcano impacts a temperature station that is used to fill in a large area, then it the volcano will seem to have a bigger impact than it really does.
And I am wondering what the satellite data says about the same island over the same time period. This would be very interesting if you have found a divergence in computed satellite measurements versus recorded land data.
I would have to agree with the possible buffer item Robert. I would also wonder about the same measurements from other locations performing the same type of measurements as Mauna Loa during that time? Who else does what they do at Mauna Loa for comparison Willis? We surely don’t have all that data coming from just one basket….. I know, get on my mouse and go find it 😉
I wouldn’t be surprised if you are right about the impact of in-filled temperatures that are extrapolated to cover a large area. This is the fundamental reason that all of the earth-based measurements are utter nonsense and the global temperature trends of GISS, HadCRUT, etc. should not be used. Manufacturing data out of thin air is statistical prestidigitation, not science.
The proper way to measure temperature trends over time is to compare each station to itself to determine a trend then perhaps average all those trends to come up with something approximating a reasonable picture of a global trend. In-filling is chicanery, the whole chicanery, and nothing but chicanery.
“The proper way to measure temperature trends over time is to compare each station to itself to determine a trend then perhaps average all those trends to come up with something approximating a reasonable picture of a global trend.”
Virtually all our knowledge of the world is based on inference from samples. We can only measure finitely many things. Was the US cold in April? We only have a finite number of measures.
This “proper way” is also sampling. You calculate trends in a finite number of places, and average trends to get a global. No different to averaging temperatures, and would give, as a matter of arithmetic, a fairly similar result.
Averaging trends – shudder!
Averaging averages simply removes all information.
Robert of Texas May 29, 2018 at 7:58 pm
Well, I suppose I should make this one a them “teachable moments” that the glitterati are always raving about …
Start by going to the KNMI Climate Explorer. Click on the “Monthly Observations” link under “Select A Field”.
Then scroll down to the “Lower Troposphere” section and click on the “1979-now: Spencer & Christy” link for Version 6.0.
When the next page comes up, fill it in like this:
and click on “Make Time Series”. It will come up with a graph of the requested data from that area. Of course, being me, I figure that’s not good enough. I click on “Raw Data” under the graph, download the data, import it into R, and put it into a more meaningful and hopefully beautiful form as follows:
No response to the solar change. Zip. Zero.
w.
Really good article. Thanks.
I just wondered that the Corialis Effect might have kept the air clear over Hawaii.
Maybe check Southern Hemisphere temperatures during the volcanoes. Maybe only the North cooled, affecting average global temperature.
On ocean buffering – an interesting research project. Not for me, unfortunately, I have not the time to run a filter through my database on good stations that are not where they might be buffered. (It does have lat/long info, but I’d have to figure some kind of rather nasty spatial bounds for the filter).
I can say, just looking at just one of the definitely unbuffered good stations (Tombstone, AZ) that any effect is definitely overshadowed by other weather patterns. El Chicon shows a -0.71 degree change in the annual mean 1982-1983 – but Pinatubo shows only a -0.05 degree change 1991-1992. (And post-Pinatubo, Tombstone’s annual mean was 2.0 degrees higher in 1993.)
Oh, before I have to self-reply yet again – those are Fahrenheit. Business school stats class presentation, they would not have grokked Celsius. Although I do remember that I was tempted to use Kelvin at the time, to see if any of them actually were listening…
The atmospheric transmission measurements at Mauna Loa Observatory form the longest data series at this premier site, even longer than the temperature series, which is fragmented in the early years. The measurements are made with an Eppley normal incidence pyrheliometer radiometer mounted on a sun tracker. The first system was installed by Jack Pales in the fall of 1957. Identical Eppleys are still used today. They are mounted on a tracker at the southeast corner of the solar deck. Extracting the atmospheric total transmission is tedious, for absorption by the water vapor column must be accounted for. There are subtle seasonal changes in the data caused mainly by dust and air pollution from Asia. While the stratosphere is currently very clean, there has been a slight reduction in transmission during the past several years. This has been discussed in the literature. The most likely reason is increased emissions from China. I have calibrated dozens of sun photometers and Microtops at MLO each summer for the past 25 years. During this time I have observed, measured and photographed a wide variety of aerosol events. I described the Eppley transmission measurements in “Hawaii’s Mauna Loa Observatory: Fifty Years of Monitoring the Atmosphere (University of Hawaii Press, 2012). I’ve lived at MLO some 229 days and nights. In 2016, NOAA hired me to calibrate the world standard ozone instrument (Dobson 83). This project required living at MLO for 64 days. I’ll be back later this summer to assist in conducting a major UVB survey of Hawaii Island.
Thank you for the work, and for the comment.
Forrest, the breadth your knowledge and experience are a constant surprise to me. Thanks much for your comment.
w.
And what do the climate models predict in response to volcanic eruptions? Big dips in temperature – mmmm
Not quite sure I understood. Are the maximum just spikes where little extra energy is added to the monthly average? You could then explain the results as patchiness of the cloud cover (then as it is).
In the maximum plot, it appears, from the change with time, that you are less likely to get a very large spike with a greater path length (is this the case in winter?) and a drop in the average because of fewer spikes. The average also drops as there is more cloud forming at high altitudes as the day progresses. Very patchy though so less of an effect on the magnitude of the largest spike.
The volcanic aerosols seem to affect the probability of getting a large spike, reducing the chance of a very large one and reducing the number so having an effect on the average. At 12 noon, the lower path length means that the very large spikes are less likely to get through but little reduction in the average, so the overall number getting through is still large. A bigger effect in the mid morning and late afternoon. A postulate (not theory) is that what seeds cloud formation differs a lot on patchiness depending on the mechanism.
Really need to see the data spit into seasons, especially comparing months of mid winter with those around the spring equinox (or 60 days centred around it).
After another 2000-3000 m of cloudy atmosphere, these spikes from clearer sky above are lost in the extra cloudiness but it would be interesting to see the if there is an effect on mid morning and late afternoon temperatures rather than mean of maximum and minimum. This could have a bigger effect on agriculture than the “climate” (mean of min and max).
Please excuse the poor proof reading. “thin as it is” and a couple more that hopeful don’t put you off.
“quod erat demonstrandum” on the the climate temperature ‘governor’ Willis! Something like this fine article gives a sad demonstration of the lazy linear thinking of the mainstream consensus ‘science’.
I recall you raising a similar point regarding the increase in solar insolation between the apogee and perigee of the earths orbit. The difference is greater than that from the 11yr solar cycle maxima and minima and yet the temperature record does to respond.
I would say you have the makings of an article here that would strike the consensus dumb. If the earth can resist temperature increases with increased insolation, why not with increased CO2.
does not respond.
Willis you said
“There is also downwelling longwave data there … but unfortunately, it doesn’t start until 1994”
It would be interesting to know how that downwelling longwave data looks like. Any trend?
If daytime max incoming energy is reduced due to particulates I would think nighttime outgoing energy could also be reduced. This might lower the Max/Min temperature gap without showing much of a change in daily average since the highs might not be as high nor the lows as low. Might be too small to tease out of the Max/Min temperatures though due to variance caused by other natural processes.
Yep, I wondered that too. Thanks as ever for an interesting and thought-provoking read.
@Willis- I was wondering about the land station measurements of insulation last week. So your article is very timely and I appreciate it.
You said- So … why was there no reduction in the temperatures anywhere in the islands from that large a change in forcing?
I would claim while waving my hands wildly that the loss of solar forcing was sucked out of the ocean to make up for the difference.
This is the document i found looking for ground Station solar insolation. It looks like one chart shows a cooling trend from 2000 of about 10 watts per meter squared per decade. So after this Micro Ice Age We may just keep stair stepping down for the next four thousand years. Stay tuned.
from satellite and ground measurements: Comparisons and challenges
Laura M. Hinkelman Paul W. Stackhouse Jr. Bruce A. Wielicki Taiping Zhang Sara R. Wilson
First published: 15 August 2009
https://doi.org/10.1029/2008JD011004
Sandy minister of future
Interesting data and a surprising result from your analyses, Willis!
The largest Pinatubo eruption was coincident with Typhoon Yunya, the center of which passed about 47 miles north of the mountain. My conjecture is the heavy rains and winds associated with the typhoon ‘knocked down’ the height of the eruption plume through direct winds shear effects as well as rain transport of significant amounts of fine particulates and sulfur compounds to the ground/ocean. This reduced the impacts on high atmospheric transparency, making the net results closer to those of the El Chichon eruption.
I’m a bit puzzled why the Mount St. Helens eruption in May 1980 do not show in the MLO data??!
j mac, the Mt. St. Helena volcano blew out horizontally rather than vertically, so very little of the SO2 ended up in the stratosphere …
w.
And to boot, MSH had low-sulfur magma, while Pinatubo – and especially el Chichon – were high sulfur.
“And to boot, MSH had low-sulfur magma, while Pinatubo – and especially el Chichon – were high sulfur.”
Answer to Willis’s question of why the 2 different volcanoes had similar effect even though they were different in magnitude?
Are there wind speed/direction records matching your data Willis? Low and High Pressure systems moving heat around to stabilise?
Like going down a rabbit warren when you start to contemplate all the different inputs to the system.
Plus the erratics, volcanoes, earthquakes, meteors.
Can you put this into your thunderstorms to show the results over time?
Warren in New Zealand
As I mentioned below, looking at the winds is next on my list …
w.
The State of Hawaii’s Kilauea has been in an eruption phase since 1983. At times VOG has covered the entire state. The big island gets dosed with most of it. One would think that air would affect the instruments atop Mauna Kea…
http://www.mikelevin.com/HawaiiOceanSunset.jpg
Its so high its above weather. Mostly.
Question…isn’t direct solar irradiance including visible wavelengths that don’t cause heating? Meaning, the irradiance drops due to light reflection back in to space, but that drop in irradiance isn’t ALL energy that warms the earth…
If only some fraction of total direct solar irradiance causes heating, then only the reduction in that fraction would have a cloud feedback effect. What is that fraction, and what is the reduction in that fraction? I don’t know, but gosh wouldn’t if be interesting to find out that the aerosols from the volcano eruptions only reduce heating irradiance by about the same amount your cloud cover decreased…
I guess the missing down selling infrared info would have answered that?
Thanks,
Roland
Since becoming enlightened just over a year ago (i.e no longer buys the ‘it’s all because of us’ dogma) I’ve developed a keen interest in Climate Change & whilst I do not yet have sufficient knowledge to offer an opinion on your findings, I want to thank you for having written it in such a readily understandable way that lay-people like me can continue to broaden our knowledge and think for ourselves
Thanks, Clare. My objective is exactly that—I envision my target audience as the “interested layperson”, someone who is fascinated by the world but may not have extensive scientific knowledge.
Best regards,
w.
i wonder if the answer doesn’t lie in wind speeds. If the sun light increases in the islands, the ensuing warmth would create lower pressure which would in turn make for stronger walker cell trade winds (and visa versa). Walker trades follow the sun and, as such don’t kick up until the late morning/ noon hours. It would be interesting to see a comparison of temperatures in the islands as they evolve throughout the day. That might be the clue to the answer to the question at hand. (iow, book ’em Dano!… ☺) Looking at figure #3, it sure seems plausible. The greatest difference in solar radiation occurs during those morning hours when skies are clear and winds are calm. Keep in mind that those trade winds blow from east to west which means they are moving cooler air in the east to the west…
Fonz, I’ve wondered about the wind as well. A reduction in wind speed could be involved. Fortunately, I have the data, and it was next on my to-do list … well, after I fire up the weedwhacker and cut the grass on the lower acre. I’ll report back on the wind question when I can get to it.
w.
Well, my curiosity got the best of me. I’ve added this to the head post.
[UPDATE] Commenters asked about something I’d considered, whether it was the changes in the wind speed that had affected the temperature. It appears that the answer is no.
The difference between eruptions and no eruptions is well within the uncertainty of the data.
Regards,
w.
Willis, hard to say how much walker trades affect wind speeds at 10,000+ feet. If they are mostly a surface phenomonon, then the data to look at would be winds at the surface. Most folks don’t realize that walker trades are not constant (like hadley trades), but only kick up in the hours around mid day, thus following the sun. And when they do, they’re rather strong. A difference might show up in those much higher wind speeds at the surface than high atop MLO (which may or may not see any effect from walker trades at all)…
Sorry, if my comments seem a little half baked here. i used to live on the kehei coast of maui and always like wading into the conversation when the pacific region comes up (even though i don’t know my backside from a cinder cone when talking about it… ☺)
Willis – great article.
The answer to the apparent conundrum is that the temperature is set by insolation reaching the top of the atmosphere and not the proportion that reaches the surface.
Convection and conduction within the atmosphere always change to neutralise any radiative imbalances between atmosphere and space by adjusting the energy exchanges within the atmosphere and between surface and atmosphere in an equal and opposite direction.
It works even when there is no water and no clouds but clouds in a water world do show up the processes in action.
Thus the so called greenhouse effect is a consequence of atmospheric mass conducting and convecting within a gravity field and not a consequence of radiative imbalances.
Stephen Wilde
Willis,
You are missing one key point: Both El Chichon and Pinatubo eruptions happened during strong El Nino. Thus, if you are assessing the effect of these volcanic eruptions, you need to consider the effect of simultaneous El Nino.