Ruminerian V – Get your coffee, you’re gonna need it.

One of the reasons I do this, is because as I was growing up, having an interest in things Geophysical/Astrophysical, there was always a search for the “wow” factor. Not everyone’s “wow” sense is geared the same… and in some cases, the scale of stuff that people are familiar with has a lot to say about how they perceive the “wowness” of it. Grabbing that meaningful nugget of data, or of a concept that totally re-vamps your experience level is way cool. It changes your world in incremental steps… or at least how you look at it.

The difficult thing is finding usable data to ruminate on, or to have some esoteric thought wrapped up in equally esoteric language. (see “e-folding” from the last Ruminerian) It’s not that people are intentionally obtuse with the language or ideas, it’s that there is a lot of technical jargon that develops out of any technical field. (How many of you know that a “gyraline modulator” is?) This post, and the others that I have written, are geared towards the person who seeks to find out more.

This, is more.

Before I continue, a bit about SO2. SO2, Sulfur Dioxide, is a volcanic gas. It reacts with water to form H2SO4, also known as sulfuric acid. Take away the water and you get sulfate, SO4. The reaction in the atmosphere goes something like this:

SO2 1 OH 1 3H2O ═> H2SO4 (1) 1 HO2

In Ruminerian IV, I ended on a pretty interesting graphic. (well, I thought it was)

It is derived from “Stratospheric Loading of Sulfur from Explosive Volcanic Eruptions” Bluth et al (1997). This plot shows the e-folding times for SO2 to sulfate conversation, and then for sulfate removal from the stratosphere.

Where this particular model fails horribly, is in how it treats the SO2 input. It assumes one sizable lump of SO2 injected to the stratosphere. Odds are that many volcanic eruptions are not going to be just one quick blast of SO2 and the show is over. For the sake of modeling influx to the stratosphere, you can probably get away with it… but you have to always be aware that this ideal treatment is going to be incomplete. Another line of thinking is that an established vertical plume can eventually propel the gases past the tropopause if it persists long enough and has enough strength.

Revising that plot and looking at the peaks in it and the narrative that went along with it, moderate sized SO2 releases have a sulfate peak about 2.07 months after the event. In winter (for whatever hemisphere) this conversion rate can be slowed by up to 20% (Bluth et al 1997) giving a peak at about 2.27 months. (30 day months). For large eruptions the curves yield 2.78 months and 2.99 months (winter).

Okay, a lot of stuff about … something. But why?

Sulfate is an aerosol. “a suspension of fine solid particles or liquid droplets in a gas.” Smoke from a fire is an aerosol. Clouds and fog are aerosols. That brown crud drifting off of the iron pellet plant in Bahrain is an aerosol. That massive black cloud that spurted out of the stacks on a steam powered Cruiser in Mayport Florida, that then settled on the Quarterdeck of the spiffy new Gas Turbine powered Cruiser moored on the other pier… that was an aerosol. (trashed a lot of summer white uniforms as the partially burnt diesel precipitated out) Even that gunky haze that you can see over New York from 30 km at sea is an aerosol (the same for LA by the way). Fine particles suspended in a gas.

In some way form or fashion, they all act upon light that is traveling through them. Reflection, scattering, refraction, absorption. You name it. If the particles are quite small, the effects are generally in the category or Rayleigh scattering. That’s what makes those vivid sunsets or the sky blue. If they are about the size of the light’s wavelength, you get Mie scattering. That’s the effect that makes the clouds appear white.

Now I deviate. As I was growing up, I used to listen to the radio. At night I could pull in stations from hundreds of miles away… during the day time, only the closer stations would show up. I had a great uncle who was into Ham radio, and he took a partial interest in my fascination with all things electric. He gave me a copy of an ARRL handbook. I never got a ham license, but I learned everything in that book… and then some. (I wound up specializing in Electronic Warfare in the military). That late night effect that allowed me to hear stations far away, is caused by ionized layers of the atmosphere.. specifically, the ionosphere.

There are three principle layers involved, the D layer which is strongest during the day, mainly absorbs radio waves. Above that, the E layer, present during the day, acts to reflect radio waves. And above that, the F layer. It’s always present, and in the day time it tends to split into the F1 and F2 layers. This is the one that causes most of your long haul radio intercepts late at night. In CB jargon, its called “skip” because that is what the signal is doing… bouncing off of the ionosphere, back to Earth, and could bounce a second time repeating the process. (no, this is not the Van Allen radiation belts, that is something totally different) “Anomalous propagation” (the real term) can occur due to a number of causes… the sun is the main driver, but meteor showers can energize the various layers also.

This rather busy plot gives you an idea of where everything is at. Note that the vertical scale is logarithmic. Just for reference, I’ve place a few altitude events and items in there for reference… such as Felix Baumgartner’s leap altitude, and the record holder prior to that, Joseph Kittinger. Also noted are high and low altitude of the ISS, and the elevation that Mt Pinatubo erupted to during it’s strongest phase.

Now for something totally new to me. Christian Junge, Atmospheric research pioneer, released a paper in 1961 announcing he discovery of the stratospheric aerosol layer. This region is the area where the nitty gritty happens with respect to volcanoes and the climate. I have spent a few days tracking down good info on the location and the make up of the Junge layer plus some of what goes on there.

It resides at about 17 to 30 km in altitude, depending on conditions. This layer is where sulfate occurs when it forms. How dense it is depends on a number of factors… one of the strongest factors is volcanic activity. A volcano can load this layer quite quickly, and as you saw from the e-fold plot, the material can stick around for a while. One interesting thing that I found out was that the Junge layer can occur at distinct elevation nodes. During heavy volcanic activity, there can be an upper and lower node. Eventually it all settles to that lower range over a period of several months.

Yet another interesting thing about it, is that it is usually there… whether the volcanoes are running or not. There is always a background level of sulfate. This is where it gets pretty wild.

At one time, it was thought that SO2 in the atmosphere (troposphere) could drift up and cause this persistent layer. With the way SO2 plagued Los Angeles, you can bet your bottom dollar that some people were chomping at the bit to blame modern society. Many of us have sat around the Café or over at Eruptions or Jon’s Blog oogleing the OMI or TOMS SO2 vertical column data. Some of the plumes we have seen are valid volcanic events, many are not. Beijing almost always has a plume drifting out over the Pacific, one plume that was seen was slap dab in the middle of nowhere… until we found an industrial facility in the Northern reaches of Russia. (Siberian Traps fans were enthralled at possible implications) Of course Europe and The US are producers… even with the emissions standards. Couple those with the bona-fide plumes we have seen, Tolbachik, Grímsvötn (for some reason a huge plume formed over Iceland two weeks after the eruption), Puyehue-Cordón Caulle … you would think that there would be a huge effect in the Sulfate formation.

It’s not gonna happen. At least not from SO2. (Note, Grímsvötn easily punched the tropopause with it’s eruption, I’m referring to the later plume.)

SO2 is a highly reactive gas. As you can see from that plot that it only takes about two and half months for it to react out to below about 10% of what was emitted. (and that’s at the stratospheres rates, it’s probably faster in the tropopause where water vapor is quite abundant) SO2 just does not have the staying power to wind up in the stratosphere due to riding the air currents. In fact, some researchers have studied the SO2 concentration vs altitude and come up with something like this:

Don’t be fooled by that really high correlation coefficient. That’s just how well the curve fit an averaged set of multiple curves generated from the data in Meixner (1984). Think of it as a general guideline and nothing more. What is important is that SO2 trails off quite rapidly with height. It just doesn’t have the staying power.

Before I press on I would like to make mention that the Atmosphere is a highly complex dynamic system. We know a few things about it, such as large scale circulation patterns, but with as much as we do know, you can bet your bottom dollar there is just as much if not more, that is not known. Here is a tidbit that most people don’t know.

Notice the red up arrows. These are the regions where low pressure systems dominate. As air rises, the surrounding air flows inward to fill the space. Where the blue down arrows are at, high pressure systems dominate. Overall horizontal circulation of the individual lows and highs is driven by the Coriolis effect … which is due to residual angular momentum from where the air is coming from. In the Northern hemisphere, Lows rotate clockwise, highs counter clockwise (as viewed from the top). In the Southern Hemisphere, the reverse applies.

Across the world, there are regions that have what are known as “semi-permanent” features… the Icelandic Low is one, another is the Bermuda/Azores high (depending on where it happens to be at) There is no hard and fast rule about what latitude something is going to be at, this is just a generalized rendition of where the boundary regions are at.
Notice that not only is the tropopause usually low over Iceland… the general circulation pattern is lofting air to the tropopause. This also applies to the Kamchatka peninsula which is also not too far south of the Polar cell boundary. (The same for the Aleutian island volcanoes)

Now we move on to the reason for the post… (hell of a lead in eh?)
Two of the more significant volcanic eruption styles… are the massive VEI-6+ explosive eruptions… and the not so explosive VEI-6+ flood basalt events. Of the two, one would think that the huge lava flow events wouldn’t have much of an opportunity to loft stuff above the tropopause. We have already seen that SO2 doesn’t have much staying power, and tends to be scavenged out pretty quickly in the area where most of the water vapor is at… down here in our little realm of existence in the troposphere.

Yet there is a way that massive flood basalts can easily contribute to the Stratospheric Aerosol Layer (another name commonly used for the Junge layer.)

It comes in the form of a little molecule called Carbonyl Sulfide. OCS.
Carbonyl Sulfide can be considered as an intermediate between CO2 (carbon dioxide) and CS2 (carbon disulfide). It has a really long persistence in the troposphere… accounting for up to 80% of the sulfur gases present. I’ve seen residence times ranging from 4 years, to 7.1 to 11 years. Basically, it doesn’t like to react. This gives it time to wander throughout the different atmospheric flows and become well distributed. And a really interesting thing happens when it is hit with ultraviolet light of about 200 to 270 angstroms. (UV-C). The bonds begin to break and it dissociates. Once it does that it forms CO2 and S2… the S2 then reacting with the H2O and OH radicals forming H2SO4… the sulfate.

Hello aerosol haze.

Okay… we have a mechanism not involving SO2 that can make sulfate. Some of the largest sources are the oceans, fossil fuel usage, even the making of concrete. (via a catalytic reaction). In general, the background level of the aerosol is not that big of a deal unless something radically increases the amount there… like an large explosive volcano. Or, a really big flood basalt event. (Eldga, Skaftar, Krafla, Þjórsá lava or any of the huge flow fields that pop up in Iceland from time to time)
Remember, OCS is ultra stable in the troposphere, but once it gets to the stratosphere where the UV-C can get at it, hello Aerosol Haze.


This article has gone through about 4 revisions before I actually wrote it. I hope you were able to read it without dozing off. If you did, it’s no big deal. I doze off reading what I think is really interesting stuff from time to time.

Note: The energy in a photon packet (or wave packet depending on how you look at it) is determined by it’s wavelength. The shorter the wavelength, the more energy per packet. 200 and 270 angstroms are the wavelengths that OCS best dissociated at when exposed to it. I don’t know why, but the ratio of the length of the two bonds is pretty close to the ratio of the differences in those two wavelengths. It’s about 1731 times the length of the bond in both cases. Why? I don’t know. I just found it interesting.

As noted there were about four iterations of this post before I actually wrote it. Here is some stuff didn’t make it in, but deserves to be mentioned. (well, since I already did the plots for it)

Stepping back from Carbonyl Sulfide… and back to Sulfur Dioxide and the usual way that volcanoes can affect the Junge layer. NASA GISS has a few models they play with. One is a compilation of the “Stratospheric Aerosol Optical Thickness” (What they have against Christian Junge is beyond me, the Junge layer is where most of this stuff is at.) One of the data products is something called the “Tau Line” and represents the average thickness at 550 nm. (that’s pretty much in the middle of “green” light at 520–570 nm.)

For those of you who are chomping at the bit over the Roaring 40’s, nothing really shows up, but they have some nice graphic of sulfate blooms and spreads for various volcanoes over the years. They also have that tau line data set.

First, let’s look at some of the more recent party poppers.

This is a plot of the Tau Line (Aerosol Optical Depth) in relation to a few volcanoes that have gone off recently. Notice that the hemisphere that received the brunt of the sulfate load depends on what volcano erupted.

Also notice that the shape of the curve pretty much follows the decay rate. The lag time between the eruption and the sulfate peak is noted. For the most part, it follows the growth and decay curves at the beginning of the post. Personally, I thought that was pretty neat.

So.. how do they compare to some known atmosphere shakers? Volcanoes such as El Chichón or Pinatubo?

El Chichón, at 17.36°N, had most of it’s effect in the Northern Hemisphere. According to Wikipedia, the Mauna Loa observatory registered a larger drop in Solar radiation transmittance than Pinatubo. However, Pinatubo (15.14°N) had a longer duration of it’s drop. It also had better coupling to both hemispheres. It also had 4.8 times the output of bulk tephra (using GVP Data).

Comparing them with those diminutive spikes over at the right hand side of the plot… those are the ones shown in the previous plot.

How is that for perspective?

Analyses and visualizations used in this [study/paper/presentation] were produced with the Giovanni online data system, developed and maintained by the NASA GES DISC. (Specifically, the tropopause elevation data)

“Stratospheric Loading of Sulfur from Explosive Volcanic Eruptions” Bluth et al (1997)

“The role of carbonyl sulphide as a source of stratospheric sulphate aerosol and its impact on climate” Brühl et al (2012)

“The Vertical Sulfur Dioxide Distribution at the Tropopause Level” Meixner (1984)

“A ThreeDimensional Global Model Study of Carbonyl Sulfide in the Troposphere and the Lower Stratosphere” Kjellström (1998)


136 thoughts on “Ruminerian V – Get your coffee, you’re gonna need it.

  1. The period between 1967 and 1980 in that Tau Line is a bit wonky. That’s the data as presented, but it seems as though it’s reconstructed data from a lost sensor capability. Just thought I would mention that.

    BTW, some of Christian Junge’s data came from the still secret at the time SR-71/YF-12 collection platform. You couldn’t ask for a better sensor carrier for that realm.

  2. Phew. I start paid work after 2 weeks off. Think after the first 2 hours I may deserve a bit of lightness and entertainment, so allow myself to insert volcanocafe in the browser’s adress bar. And then that? Oh my. Nonononono. That’s evening stuff. But I’m looking forward to reading it, no doubt.
    Have a nice day!

  3. Multiple wow moments in this post Lurking. Your plots just keep getting better and better, if that were even possible!

    Amazing how strong the equatorial boundary works for Merapi (7.5°S) but not for Pinatubo, probably a combination of the size of the eruption and the ferocity of the typhoon that hit the Philippines at the same time. Fernandina is bang on the equator and Fuego at 14°N by comparison. The e-folding rates make an awful lot of sense.

    But one question, where does carbonyl sulfide come from? Does it form in eruptions or in the atmosphere after an eruption?

    • It comes from the oceans, hydrocarbon usage, even the mixing and curing of cement. It is the priciple sulfur gas of the sulfur cycle. Foliage takes it up, and the tropics are a major sink for it.

      As for volcanoes, the best number I have found is about 0.3 pct of the SO2, but thats not a likely a good number. I’ve been trying nail that one down.

      The fact that is so long lived in the absence of UV-C is what makes it a strong player.

      I don’t think that volcanic originated carbonyl sulfide becomes a major issue unless you have a large flood basalt event.

    • BTW, Pinatubo punched the tropopause about four times if the Wiki article is accurate, 19, 24, 24, and 34 km for the biggest during the Typhoon. (3 hr sustained)

    • I think missed the “where does it come from” bit.

      OCS is one of the simpler molecules. H2S, CO2, SO2, CS2 are all pieces in the various chains of chemicals that other more complex molecules are formed from. When you have sulfur laden material being acted on by heat, water (hydrogen and oxygen), and CO2 (and CO), OCS is one of the possible products.

      Metal sulfides and other minerals (such as Gypsum) are probably sources.

      • One thing i am going to do when I have time, is to look at the 20.1 to 16.2 million
        year data about the Columbia flood basalts that had to do something to the climate.
        major events. The CorRiBa basalts have little sulfur in the rock, but I suspect the
        degassing at the eruption sites may be different..
        I’m going to start digging…

  4. Good morning – I think I want to say thank you for No 5 but I have a lot to do this morning and now – yeah – the kettle is on ………..

  5. Brilliant rumination! Now I am wondering if there are any other mechanisms by which the sulphur could disperse such that the h2so4 measures (subject of a previous rumination of yours) may not have included all sulphur generated. Need to do some thinking/ digging becuase I suspect that just maybe this isnt the whole picture.

      • Question – Eyjafjallajokul didnt really even produce a blip on the stratospheric optical depth, yet definitely had an eruption plume high enough to send sulphur up there and went on for a few weeks at this level (am I correct in this Lurking?)… so, could there be something e.g. an association between eruptive matter that is high in very small silicate particulates and low recorded sulphur outputs? I am thinking of some form of reaction between the sulphur and the silicates to produce silicon sulphide during the eruptive process which locks up the free sulphur and limits the sulphur signature. Wild guesses here..

      • Eyjafjallajökull’s plume only made it to about 9km. The tropopause in that region ranges from about 9 to 12km, depending on the time of year and prevailing weather conditions.

        So… it was hit or miss.

        Though it was quite pretty and took us all by surprise, it wasn’t particularly energetic. About a year or so later Grímsvötn erupted more than the entirety of Eyjafjallajökull in about 7 hours, then shut down.

  6. Had Coffee #4 but my small brain needs more time to adsorb all this information. I think I will have to go back to the first rumination and work through again even more slowly. Lurking you never cease to amaze me!

  7. Renato Rio says:
    January 6, 2013 at 14:30
    Hey there everyone!
    Back to the heat, from my two-week trip to Europe.
    Still have to catch up with all the news.
    Miss you guys.

  8. An impressive post. I had to print it out to get my head round it (or start to get my head round it)!

    Thank you GeoLurking. 🙂

  9. Some things that may be vague, so let me clarify. (I really should have emphasized it)

    1) There is always a background level of Sulfate. The most likely source is carbonyl sulfide (OCS) and Dimethyl sulfide (organic origin).

    2) Not all volcanic eruptions have a significant sulfur component. Taupo’s last big eruption is a prime example. (Hatepe eruption). It had more than enough “oomph” to do reach the stratosphere, but little to no record in the ice cores. Any blocking effect of the “roaring 40’s” is not going to be very effective on anything lofted into the stratosphere.

    3) The SO2 to Sulfate conversion curve is for SO2, not OCS. However, once the sulfate from OCS is made, it will follow the second curve.

    4) Really, the only radical or weird thing that I am stating, is that OCS is probably the way that large scale flood basalts can affect the stratosphere. I have always had a problem in seeing how a non-energetic SO2 release could do that. SO2 decays out (converts to sulfate) much too fast to reach the stratosphere by just drifting around. Most of it stays in the troposphere and sediments out once it becomes sulfate.

    And yeah… I need coffee also. 😀

    • Good question. How high would the gas release from something like the Eldgjá fires be? It is not your classic plinian eruption, but there must have been an enormous amount of heat released and convective forces would do the rest, wouldn’t they, or am I missing something basic?

    • I’ve seen mention of long period hot areas being able to establish a column much like a chimney that could do it… but I don’t have a lot of confidence in the idea. Weather systems are just too dynamic for it to really have much of a chance to remain stable. (just look at Tolbachik)

      But, the large scale events in Iceland do cover a larger area… and there is that item of “location, location, location”

      Where is Iceland Located? Right about 63°N to 68°N.

      What generalized atmospheric flow pattern sits at about 60°N? The boundary of the Polar and Mid latitude cells. What direction does the air tend to flow? Upwards via the semi-permanant lows that show up there.

      It could be a combination of all of it.

      • The whole thing is quite intriguing. On the one hand we have spikes in SO2 in the ice record that are demonstrably from volcanic sources. On the other hand, we have the volcanoes to put it up there. But the high SO2 producers tend to be non-explosive flood basalt eruptions like Laki which pump out a ton (or three) of SO2 but these aerosols don’t have the wherewithall to get to the stratosphere on their own, and according to Lurking, the SO2 would decay in the troposphere pretty quickly unless it took another form like OCS.

        This leaves weather patterns, conversion into carbonyl sulfide and explosive high SO2 eruptions as the only culprits to explain the spikes in the ice record. Kasotochi and Sarychev Peak are good recent examples of the latter. El Chichon is an even better example, erupting a “high sulfur anhydrite bearing” (GVP) magma.

        So the size of the eruption is not the only defining factor in whether an eruption leaves a signature in the ice record but the SO2 content of the magma is also critical. (well doh)..

        BUT, if we take a step back, it is not the SO2 record per se which interests us but the question of whether an eruption will lead to the notorious volcanic winter that has often been invoked by disaster mongers. The way I have understood it, aerosols such as SO2 are critical because they stay aloft longer, but what other particles erupted by volcanoes demonstrate a similar ability and could shield the planet from solar influx? We saw how the ash from Eyjafjallajoküll stayed lingering around so long because it was so fine and there was a curious lack of rain. What was the ash from the Hatepe eruption like? Was it so coarse to just fall back down to earth? Were there no particles fine enough to stay aloft (electrically charged particles perhaps?).. If such particles exist would they show up in the ice record too?

        /questions of an ignoramus

    • Are you assuming that any event that would project sulphate or sulphate containing compounds into the stratosphere would originate solely from the volcanic eruption?

      Large / extreme weather systems can impact the stratosphere (talking large thunderstorms, etc..). How about the scenario where ash in the troposphere is circulating as “normal” but then meets one of these larger weather systems which carry the ash up to the stratosphere?

      • From the little bit I read (and it is admittedly above my head):
        is that they can distinguish between the sources on the basis of the sulfur isoptopes between oceanic sources, volcanic and anthropogenic sources. The oceans account for most of it but here’s just one quote from the paper do excite your interest:
        “After ruling out anthropogenic, continental biogenic and mineral dust as being significant sources of sulfate in our sample, this leaves volcanic sulfur emissions as being the only potential significant source of continental sulfate in our samples”

        • Not the only one with syntax issues 🙂

          I was trying to paint a scenario where a volcano erupts, putting SO2 etc into the troposphere. The SO2 etc circulates in the troposphere until it meets a large extreme weather system which then pushes the SO2 etc into the stratosphere.

          If that scenario can work, you don’t need a big VEI eruption to get the SO2 etc into the stratosphere.

  10. Again, an intriguing rumination. Being the Enfant Terrible that i am, I cannot help but check known facts and papers:

    Eyjafjallajökull – Fimvörduhals. The reports do not mention carbonyl at all, neither solid nor gas. The gas flux report of April 1 – 2 (Fimvörduhals) specifically mentions 3,000 tons of SO2/day and 30 t/d of HF.

    Grimsvötn. The only mention of sulphur is SO4 found in leachates.

    Thus I’m sitting here thinking “Great idea! But where is the carbonyl? Has Lurk stumbled onto something previously unthought of or is it a wild goose chase?”. Definitely deserves to be the former, but…

    • The first paper looks at gas emissions on 1st and 2nd April 2010 but a lot happened before then and then we had the Eyjafjallajökull eruption itself later on. Two questions spring to mind:

      Is timing important – i.e. could carbonyl sulphide be emitted during a different phase of the eruption? and,
      Do they test for carbonyl sulphide?

    • I like enfant terribles. 😉 If I understood Lurking correctly, the OCS avenue is only a small part of the whole parcel but it could be something that adds significantly to the total impact, particularly when you factor in time.

      • Yeppers. It’s a tiny fraction.

        My goal was to find a mechanism that gave the monster flood basalts a stratospheric effect.

        How the longevity of OCS vs. the sheer quantity of SO2 measure up I don’t know. I’m not really sure where to start in that comparison.

        Again… the volcanic originated OCS (in my thinking) is only a big player in the large flood basalt eruptions. In “normal” large volcanic eruptions (explosive), I think the SO2 effect would completely swamp any detectable OCS contribution.

        • Well, we know that the 1783 “Skaftá fires” eruption deposited huge amounts of SO2 enough to cause a “vog” thick enough to prevent ships leaving port for days over large tracts of Europe (England, Bergen, Prague, Le Havre). It’s claimed it affected areas as far away as Egypt, the Arabian peninsula and India. It would seem that stratospheric spread was not involved, so what was the mechanism that transported the SO2?

  11. Speaking of which – ground deformation at Grimsfjall. With the eruption, the up component dropped from +30 mm to -260 mm. Right now, it sits at about -15 mm, so it has rebounded to almost to the pre-eruption level…

  12. Here is a better reaction equation not violating the law of mass action (number of atoms have to be equal on both sides of the equation):

    SO2 + OH + 3H2O + O2 —> H2SO4 + 2H2O + HO2

    This is the summary of 4 reactions from Bekki 1995, who originally wrote the above shortcut version of the 4-step reaction scheme ignoring the oxigen for some reason unknown to me (

    This out of the way I can now continue reading…. 🙂

    • I’ll have a look at the article, but HO2 cannot exist, it must be a convenient way to balance the equation. You cannot have 2 atoms of oxygen (charged minus 2) with only one hydrogen (charge plus one). I’ll try to find something

    • Thanks for looking at this from an equation balancing issue. I knew it had to be taken into account but wasn’t sure what they had done to get it into that form, and it’s been a few years.

      …the SO2 to sulfate particle conversion seems to be triggered by a photochemical reaction producing radicals…

      And the OCS bit “turns on” at about 200 nm and 270 nm. Up in the UV-C range. UV-C is blocked down here in the troposphere, but is available in the stratosphere.

      “Up there”, “Down there” … I tend to think in Frequency, so for me it’s “Up There”

  13. This is a very stimulating post, ranging from electronic warfare to geochemistry! So many leads to follow…I feel busier than during those septuple name-that-volcano riddles 😉

    • I’ll be content if some enterprising Geosciences student happens through here and gets an idea. All I’ve done is gather arcane bits of info and had an idea. I can’t prove any of it.

      …ranging from electronic warfare…

      And I didn’t say a thing about surface ducting, forward scatter or burn through ranges… 😀

  14. Ahh the runt dogs. What a pair.

    I got stuck pulling the meat off of a deer quarter to make sausage. Mixing it with pork and grinding it, the house has the aroma of a butchery… The two runt dogs are freaking out at the smell of fresh meat.

    My wife is watching TV… some program called “The News.” It’s an obscure program where some bobble headed idiot tells you what to think. Anyway… they do a feature on a guy named “Bob White.” I snicker. The wife looks over at me and asks ‘What’s so funny?’

    I tell her “The guys name.”


    “It’s the guys name… it’s also a kind of bird” As I’m leaving the living room I do a Bob White call.

    The dogs rush me. I had forgotten that they were already primed for some sort of table dropping as I’m working on the sausage.

    You know dogs are psychic right? Well, at least they think they are.

    That’s why they sit there and stare at you… trying to will you into dropping something with the power of their mind.

  15. Very interesting post GeoLurking
    Another factor about big eruptions is water vapor coming from the eruptions.
    Both Eyjafjalla and Grímsvatna eruptions did evaporate lot of water, when it melted the ice above the craters, and the water can condense and wash away So2 from the plume, or not.
    But Laki eruption probably started on dry ground an later the lava filled the riverbed of skaftá, so the river totally evaporated, and later the lava filled Hverfisfljót canyon and that river also totally evaporated for some time.
    So water vapor can be big factor in the chemistry of So2 reactions.

    • Nice point. This could explain a lot. El Chicon was high sulfur anhydrite bearing magma erupting without the presence of water. Taupo had a lake sitting on it (at least in the early stages) and was low sulfur.

  16. Getting back to my point that we should not only concentrate on sulfur when it comes to volcanic winters I started a rudimentary search of global temperature over the last two thousand years. A bit of googling led me to this chart from Loehle and McCulloch. I am very nervous about researching climate data as the whole field is so fraught with politicizing on both sides and I have no idea who to trust or if this data is accurate:

    However, that said, the chart does show a precipitous drop in global temperature just before 200 CE. This might be Taupo induced. It is hard to find a comparable sudden drop in temperature. But a note of caution: Wilson dated the Hatepe eruption of Taupo at 186 CE, coincident with reports from China of meteorological phenonmena. Sparks dated it using radiocarbon techniques to 233 CE ± 13 years. I’ll do some more digging. Does anyone know of other or “better” records of global temperature over the last 2000 years?

      • The last large eruption of Tianchi volcano was regarded as one of the largest eruptions over the world in recent 2 000 years. Although there have been a lot of studies on the C14 age of the gagatites from the primeval forest that was destroyed by that large eruption. a wide scope of the C14 age has been given. such as 650-916 AD, 915-1334 AD, 750- 960 AD. and 850-1040 AD

        Best I can figure… “gagatite” is either some form of coal, charcoal, or jade.

        This is from one of the random Pay to Play articles on Springer… I forget which. I tend to gloss over papers that they pimp out.

        Search terms were Changbaishan and Tephra.

        • Ha. That’s about as accurate as I once found. Kind of bizarre that an eruption of that size is not recorded in the written Chinese record. I mean, it is not THAT long ago and China has had a modern civilization for a pretty long time.

      • A couple of my posts must have ended up in the spam box that are relevant to this… I’ll wait to see if they reappear

  17. Oh grief, it gets worse. Here’s a well researched paper from the field of dendrochronology (study of tree rings) on past global cooling:
    While they find a strong statistical correlation between tree rings and the ice core record, wait for it, there is NO sign of Laki in 1783, Tambora in 1815, Katmai (Novarupta) in 1912, the Hatepe eruption in ca. 181 or Baekdu (969) in the record. WHAT?? So much for volcanic winters.

    • You have to take tree-rings with a grain of salt.

      Typically, “treemometers” are only reading part of the year… specifically the growing season. Additionally, trees have a crap load of other variables that determine how well they grow… the availability of water is the greatest.

      Then you have to look at what the researcher did… was there selection bias that tossed out the trees that didn’t support the researchers preconceived notions? Were a few trees more heavily weighted than the rest (hello Yamal06).

      Have the the other formerly supportive dendrochonologists been semi-privately berating said researcher for shitty work?

      Yep.. a lot of stuff goes into it.

      Coincidentally, David Archibald over on WUWT brings up the potential effects of volcanic events during a cool phase.

      (Natch, Dr Svalgaard beats on him about modern warm period. Dr Svalgaard shows no evidence of in his research, part of which is the observation and reporting bias of Wolf, Wolfer and follow-on sunspot counting entities and organizations. Their Sunspot Working Group is trying to de-funk the sunspot record so that it doesn’t suffer from biased counting… which it does. Put all the counting periods on one scale and the entire idea of a modern “grand maximum” goes away. Usoskin’s paper was written with it in mind… but he is part of that working group.)

      • That is precisely what I feared… there is so much noise in the debate it appears virtually impossible to correlate climate data to large eruptions. It appears that there is some correlation between large eruptions and global cooling (Pinatubo, Tambora) but it is going to be difficult to establish a strong enough connection to justify giving everyone the heebeejeebees:
        1. the climate record itself is fraught with the risk of misinterpretation and subject to intense debate
        2. the resolution of the historical record deteriorates over time
        3. some eruptions (like Hatepe and Kuwae I think) have been dated based on meteorological data rather than other methods (a case of cart before the horse)
        4. dating volcanic eruptions still seems pretty inaccurate. To obtain a strong correlation with the ice record or tree rings, the date of an eruption really needs to be within a timeframe of 5 years or less. For eruptions, this is pretty utopian the further back you go.
        5. despite a strong statistical correlation between tree rings and ice cores (Salzer and Hughes) this does not necessarily imply a volcanic cause or indicate that temperatures fell globally because of an eruption rather than some other factor.
        6. more bizarrely, seriously huge eruptions do not seem to have left much of a trace in either the ice record or in tree rings. This could be due to the season, weather patterns, or even the nature of the eruptive material (low SO2, coarse particulates etc.)

        • Very good points, Bruce! To my mind, it seems as if it is assumed that a volcanic eruption will always disrupt and inhibit, but is that actually the case? CO2 is actually a growth accelerator as it’s the primary “food” of plants and unless an eruption also emits really colossal amounts of SO2 (or stratospheric ash), enough to inhibit growth by reducing the amount of sunlight (direct scattering or causing cloud growth) that reaches the plants or by poisoning them (precipitation in the form of SO4), volcanic eruptions would be beneficial.

          • Exactly, people seem to take it as given that a huge eruption will have a massive impact on the global population but I am having increasing doubts about the widely accepted concept of a volcanic winter. I am not saying it never exists as there is obviously some connection between certain eruptions and the weather but I do seriously think it only occurs some of the time and then in specific circumstances.

          • Thanks Alyson.. yet another good link. Did you see I posted the link to the impact crater south of NZ for you in the last thread?

    • Tree ring samples were taken from Western USA (HI5); northern Finland; and, YAM (Asia?).

      Laki occurred in Iceland and dumped most of its emissions in Iceland, the UK, France, Italy and Germany (may be other sites too) but very little if any of the fall out would reach the USA, YAM and northern Finland. Laki was mainly a fissure eruption(s) so most of the emissions would stay below the stratosphere – there are no contemporary reports that indicate weather patterns that would shove the emissions into the stratosphere (but this is based wiki). You might possibly expect to see northern Finland show some evidence of Laki – however, that might be small as northen Finland could have been on the edge of the weather system that distributed the fall out.

  18. Found this which is interesting on SO2 photolysis in the troposphere, but what I was looking for is a paper that looks at the chemical composition of volcanic ashes. My thought is simply this – that in the massive energy release of a volcanic eruption, stored S02 could be easily ionised and thus would become highly reactive with other chemicals existing within the magma, and that reactivity would increase in magma that is released in a particulate format as volcanic ash i.e not all SO2 stored within a magma chamber would be released in a gaseous format. If this were the case then an analsysis of the ash (as opposed to the magma that may flow) may show varying levels of differing sulphates and sulphides within its chemical composition which may account for why some eruptions produce less atmospheric SO2 or OCS – i.e non gaseous particles. As yet I cannot find such analsyses for chemical compositions but will keep hunting.

    • Then look for the geochemical composition of various tephras and magmas.

      Many sources give you the basics (SiO2, TiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O, and K2O. Occasionally P2O5.

      And the more in depth reports provide the Rare Earth Elements

      If you will note, there were no sulfur compounds in that list. It it quite possible that sulfur in mineral assemblages, is freed up and released when the temperature gets high enough. Gypsum and Pyrite both have an upper range where they begin to break down (chemically).

  19. Magnitude Mw 5.8
    Region AEGEAN SEA
    Date time 2013-01-08 14:16:09.0 UTC
    Location 39.64 N ; 25.55 E
    Depth 11 km
    Distances 193 km NW Izmir (pop 2,500,603 ; local time 16:16:09.5 2013-01-08)
    69 km W Ezine (pop 15,677 ; local time 16:16:09.5 2013-01-08)
    35 km SE Moúdros (pop 1,036 ; local time 16:16:09.5 2013-01-08)

  20. Mentioned as an aside in the Martin & Bindeman paper:

    As an example, we did not find any sulfate in samples from 1m thick ash layer from the Toba supereruption (74 ka) in Malaysia.

  21. Nevado del Ruiz seems rather lively.

    On another note, hopefully Carl will eventually come back to writing. He had a talent for making very technical topics easy to read for those of us who aren’t number crunchers, or familiar with all the technical jargon & nomenclature that comes up in journals or academic papers.

  22. OT: anyone know what the Northern Lights are doing at the moment? Saw some light green clouds over London tonight, which usually means that someone a few hundred miles further north should be able to get a good view of the Aurora.

    Missing IMO / Mila’s map of the Aurora Borealis since the upgraded their webcam pages 😦 but they are reinstating some more cameras 🙂

    • I think the interesting part here is how sharp the inflation has increased in december. Look at the sharp spike in inflation rate recently.

      • 8 cm in a year? That’s nothing, especially for Campi Flegrei. During the two most recent episodes of uplift, the ground rose 1.7 and 1.8 meters during a period of four and three years respectively. That’s at least 40 to 60 cm per year.

        The only caveat is the molluscs 7 m high on the temple pillars at Pozzuoli as they indicate that the Flegrei is already at an inflation of +10 m or so above the minimum – not all of that can be due to hydrothermal activity even if the recent episodes could. I guess it’d be fair to say that those +10 m are magmatic in nature in which case we could guesstimate a ballpark figure for eruptible magma.

        Using the 2x rule-of-thumb, +10 m indicates an influx of +20 m. During 2000 years, such large amounts of magma will not have cooled significantly – except by heat transferral involved in remobilising older magma. Let’s add a hypothetical +50% for that for a total of +30 m of 850C hot, eruptible magma.

        Since caldera-forming eruptions tend to destroy magma chambers and subsequent ones tend to be smaller, at least cf the initial one, let’s assume a series of 150 cu km Campanian, 40 cu km Nepolitan and 25 – 40 cu km for the future one with a 25% emptying rate. That’d give us a present-day magma chamber on the order of 6 x 8 x 2½ km. With such a magma chamber, even the layer of eruptible magma 50 m thick hypothsised from the +10 m inflation over the past 2000 years corresponds to a scant 1½ cu km.

        Unless my guesstimates are horribly wrong, it would seem a full-scale caldera eruption is tens of thousands of years away at present. However, an Astroni-type eruption (~½ cu km in seven blasts, deposits mainly in the form of pyroclastics from base surges just over 12 km from Naples city centre) is definitely not and could be no more than years or tens of years away.

        • Campi Flegrei is certainly still dangerous whether it could go caldera or not. It can still put out large eruptions ala Vesuvius in a highly populated area, which is part of the problem.

          I agree with Carl’s earlier sentiments that Ischia is the more worrisome candidate for doing something catastrophic.

          • I do not entirely agree.

            If you intend “catastrophic” to be interpreted as “a very large eruption, VEI 6+ or even VEI 7”, then Ischia could indeed be the most likely candidate – but then we’re talking about thousands if not tens of thousands of years from now.

            But the most dangerous, likely and certainly catastrophic (with knobs on) would be an Astroni-type eruption. Even if it only rated a VEI 3 to 4, the pyroclastic base surges of such an eruption could easily kill tens of thousands if there was little or no warning or if warnings were ignored (the Aquila Verdict could see to that being the case). Just take a look at that satellite image, locate the edges – where such vents are most likely to be – of one of the several nested calderas and draw circles representing 3, 5 and 10 km radii and recoil in horror at how many people could be at risk from such an eruption.

            If that’s not enough of a disaster for you to dally with, I don’t know what is.

        • … maybe. I hate to provide fodder to any doom mongers who may be lurking here but remember that caldera forming eruptions that originate from rhyolitic chambers don’t necessarily need to inflate to form. The erupted material is by definition not juvenile material but recycled crustal material that could possibly melt in situ if the heat flux is high enough. If such proto-chambers already consist of crystal mush, repeated mafic injections will keep them close to the melting point. I suspect the yo-yo-ing of large calderas to be primarily a response to such mafic injections (among other things, such as down-sagging and magma migration into sills etc, as well as volume fluctuations from phase changes). The main thing is that injections of new material from below don’t add so much volume as they add heat into the system. Once you have a nice big pot of crystal mush all you need is a ventil, an opening, fault failure, etc. and decompression melting will do the rest for you and that huge body of crystal mush can turn into eruptible material very quickly, and all of this with little inflation. A number of recent papers (e.g. on Santorini, Whakamaru) have pointed out how rapidly large rhyolitic magma chambers can form.

          • This also goes hand in hand with the articles that were going around over the summer on how “supereruptions” can be primed within a really short period of time (geologically speaking).

            As for Ischia waiting thousands or tens of thousands of years from now to erupt, what makes you say it would take so long with such certainty? I would agree, the odds point to the fact that it’s not likely for Ischia to go caldera within the next 500 years, but based off the resurgence of the Ischia system and the fact that it hasn’t had any notable eruptive events within any recent time, I feel that if it really wanted to, it *could* go caldera in the current situation (Don’t underestimate the effects of water on a potential eruption here. Water could easily turn a VEI 4-5-6 eruption into a caldera forming eruption if it were to gain access to the magma chamber, which isn’t that unlikely given the fact that it’s an island on the mediterranean).

    • in addition to the detected ground deformation, scientists also measured increased numbers of micro earthquakes, a rise in temperature and in particular, an increase in the proportion of the gases of magmatic origin at fumaroles in the Solfatara crater.
      As the hydrothermal system is closely connected with the underlying complex magma chamber of the Phlegrean Fields, new magma movements could in fact be the culprit for the observed changes. Whether these, and if so when, will lead to a new volcanic eruption is currently uncertain.

      Bold added to deflate the expectations of the doom crowd.

    • In the caldera there are active fumaroles, the biggest of which is the “Bocca Grande”. In the centre is a mud pool with a fissure from which meteoric water and clay material combine to form the mud. The elemental compositions of the mud suggests that it originates at temperatures of around 170 – 250C. It contains trace amounts of Barium, Sodium, Magnesium, Vanadium, Arsenic, Zinc, Antimony, Iodine, Rubidium amongst others and Bocca Grande is surrounded by deposits of rare Sulphur compounds including Realgar, Cinnabar and Orpiment.

      Realgar → arsenic sulfide
      Cinnabar → mercury(II) sulfide
      Orpiment → monoclinic arsenic sulfide

    • It’s designed for Flood Basalts, but using a TiO2/FeO ratio of 0.1309 for Campanian Ignimbrite and Neapolitan Yellow Tuff, a rough estimate of the sulfur in the parental melt comes in around 1288 ppm.

      This is not what this relationship was intended and could be quite wrong. It was intended for Flood Basalts and not explosive eruptions. I do not know if the relationship holds true in this implementation.

      y=534.9+5751x is from analysis of figure 4 from:

      “Gas Fluxes from Flood Basalt Eruptions” Self, Thordarson and Widdowson (Elements Dec 2005)

      (In case you have missed by previous caveats: I am not trained in this field and it is not my specialty.)

      Geochemistry for the Tuff and Ignimbrite is from:
      “Magma chamber evolution prior to the Campanian Ignimbrite and Neapolitan Yellow Tuff eruptions (Campi Flegrei, Italy)” Pabst et al (2007)

  23. This certainly is all stretching the grey matter….

    Sometimes I feel really thick. I was reading earlier in the Radio Times (television programmes magazine) about JB Priestly’s invention of soda water using sulphur and chalk to carbonise water and thought I might be able to add something to this discussion but the evidence I googled led off in so many different directions – like baking soda and egg white to clean silver, that i tried then to go back to basics and found this….

    ‘Baking Soda Volcano
    You will need:
    Newspaper strips
    Wallpaper paste (or make a thick paste using flour and
    Plastic bottle
    Baking Soda
    Red and Yellow Food Colouring (optional)
    Liquid dish washing soap

    What to do:
    Make a papier mache volcano around the plastic bottle using the
    newspaper strips and paste.
    Wait for the volcano to dry out completely.
    Place your volcano in a container to catch any mess.
    Add some baking soda into the bottle.
    Add a small amount of liquid soap and a few drops of food colouring.
    Pour some vinegar in and watch your volcano erupt.
    You can even get creative by painting your volcano to look like a real one or
    by adding different colour food colourings in.

    How does it work?
    The chemical reaction between baking soda (sodium bicarbonate) and
    vinegar (acetic acid) produces carbon dioxide gas (CO2). As the carbon
    dioxide gas is produced, pressure builds up inside the plastic bottle, until the
    gas bubbles (thanks to the soap) out of the ‘volcano’.
    Real volcanoes also produce carbon dioxide (CO2), along with a lot of other
    different gases such as water vapour (H2O), sulphur dioxide (SO2), nitrogen
    gas (N2), hydrogen gas (H2) and carbon monoxide (CO).’

    Just couldn’t resist posting it here!

    And thanks Bruce for reposting my link to the impact crater. I saved it again and then saw what it was called and that I now had it twice – cheers!

    • Take an egg white, run it in a blender for 2 minutes or so with 2 teaspoons of sugar. Add several marshmellows and continure blending.

      Pour into a bowl and set aside.

      Pour 4 cups of (not hot) coffee along with a cup of milk into the blender, as the blender is running, slowly add about two cups of vanilla ice creame. Once the mixture is well blended, pour into large tumbler, top with the eggwhite-sugar mix.

      It’s not “espresso con leche y whisky” but it will do. (and you can still think afterwards) This was my drink of choice in Rota. It came about because of the advise of never giving coffee to a drunk since all you get is a wide awake drunk.

      I imagine that Starbucks™ could make a tidy profit off of that concoction if they put thier mind to it… of course they would probably charge $12 USD a drink.

      *any of the good “black lable” whiskeys will do. I prefer Jim Beam over Jack Daniels. (woke up in the wrong bed after a new years of drinking JD. That came about because we had to mix our own drinks. And when you mix your own… you tend to be more liberal with the alchohol as you get more inebriated, and it get’s really difficult to pace yourself. If your drink can support a flame.. it’s probably too strong. but then it’s usually not wise to let an inebriated person play with fire.)

    • Re: model volcano…

      but how do you simulate the inigbrite emplacement? Most (but not all) parents would get upset if you exposed their kids to authentic pyroclastic density currents.

      • LOL – most parents would indeed prefer not to have too much mess from pyroclastic flows on the kitchen table.

        Where I was originally headed though was the connection between sulphur and chalk, or rather, in the way that adding water produces bubbles, dissolving the sulphur and the chalk, and producing carbon dioxide in the water. Where does the carbonyl come into it? Is this relevant to the disappearance of sulphur from some eruptions?

        A simple ‘No’ may be the answer………….

  24. Tolbachik seems to have virtually stopped in the last 2 days ago. The smoke plume stopped on occasion, and yesterday it looks as if there maybe have been no plume at all (although there was some light being emiited at the erruption site before dawn). Its a shame because i just figured out how to automatically capture the stills and convert them to a timelapse video…I need a new Volcanoe to point my script at.

    • “Prof Kimura also claims that there have been a large number of phreatic eruptions – explosions of steam caused by heating of ground water from rising magma – around the mountain.”

      Hmmmmm, did I miss them???

      I also liked this excert: ‘Prof Kimura believes that aside from the Tohoku earthquake there has been an overall increase in more “normal” seismic activity around the mountain – particularly on its northeast side.’

      Warning – normal seismic activity approaching!!

  25. wow nice post Lurking 🙂
    I had a thought about Nabro – that had very high SO2 emissions (these images apparently show the largest seen from space on earth) yet no mark on the stratospheric optical depth.
    I’m guessing that’s because the ash cloud only reached about 13.5 km according to vaac so didn’t make it into the stratosphere?

  26. This post made my head hurt. That means its a good one 🙂

    What I am getting from all this is that the various proxies for climate, SO2 and dating of past major eruptions may have been somewhat over-interpreted, and the record of eruptions before ~1000AD and our knowledge of their effect on climate is much flimsier than has generally been portrayed.

    • Oh I think that it’s a very important general fact that “we” have understood a lot less about what factors influence the climate (and not weather) and how than “we” think.
      That what makes my alarm bells ring when I read more and more articles from people who have ideas how we could “fight” climate change / global warming by starting to blast stuff into the atmosphere or whatever wild phantasies. Playing inter-/suprastellar power… Ten years after having started what “we” believed would cool us down 1.5° “we” come to the conclusion that we iduced an ice-age, what is quite worse dealing with than some warming… I mean, as we’re talking of human existance’s scale stuff…
      And I think it was Pierre Dac that said that if you see a man opening the car door for a woman, one of both (the car or the woman) are new…
      Now what does that have to do with what I said before? Nothing… Ehm. Yesyes.

  27. Well here is the Tolbachik Timelapse for the last few days, I captured the 1st 20 seconds of the vidoe on the 7th Jab ~14:20 GMT), then re-started it later @16:20 GMT.

    You can see that the light source dissappeared..maybe from cloud, but at sunrise ~35 seconds, the cloud looks think enough that the light source (lava founatain?) has gone. Then on the 8th, its very cloudy and either there is no smoke, or its hanging very low to the ground with the rest of the clouds.

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