Volcanic cooling, turbidity

Posted: June 14, 2013 by tchannon in Analysis, atmosphere, Natural Variation, volcanos, weather

Figure 1

Pinatubo produced the 2nd largest volcanic eruption of the 20th century after Mt Katmai decided to vanish in 1912, heard 1500 miles away.

Recent talk about volcanic cooling fits quite well with investigation ongoing at the moment about turbidity and the instrumentation of solar measurement from earth.

A few days ago I posted an article on Mt Katmai which shows the minor effect on turbidity (clarity of the atmosphere). I hadn’t looked at temperature data until yesterday, adding a comment, plot repeated below.

Figure 2

Dramatic cooling? The linked Alaskan site provides much more information which includes the effects did not reach the southern hemisphere, so an effect would appear in the above plot as north only.

Pinatubo erupted at the start of September 1991 and is located in the Philippines at 15N, which is in or close to an ascent region for major atmospheric circulation cells.

Figure 1 is scruffy, I’ve yet to continue work on the hovmoller plots, is for RSS satellite lower troposphere. RSS because it completed database update first, UAH is similar.

Below is more


Figure 3

Middle troposphere.


Figure 4

Lower stratosphere where apparently Pinatubo injected ash.


Figure 5

Top stratosphere, data starts later. Never plotted this data before.

Tropical band seems to be + 21.5 degrees so it includes 15N

I’ve looked at quite a few papers on Pinatubo and turbidity where the impression I get is not a lot happened, not even in some data. An instance is from South Africa where turbidity monitoring happened to be in progress. Remarks the air is clear there but Pinatubo is only detectable in some station data. This suggests not a lot crossed into the southern hemisphere.

A good search term is

pinatubo turbidity

Discuss, comments. I’ve not spent a long time on this, just enough to produce a post. You can find the PDF etc. avoids my cherry picking.

So what am I doing wrong? Where is the drama?


  1. dp says:

    I’m quite surprised at the apparent (visual) correlation between the Hovmoller plots and the sea ice extent charts for both polls found elsewhere. I hadn’t noticed this earlier. It would be very interesting to add a line plot of sea ice extent on top of the Hovmoller chart to get a better sense of timing.

  2. tchannon says:

    As it happens I have a large post on Arctic sea ice moving towards ready, contains some surprises.

    Ages ago I did look at whether satellite lower troposphere temperature related to sea ice and to a degree it does. What this means given the effects of ocean currents and winds is moot.
    I don’t want to side track too far.

    This article here is supposed to produce a surprise given the claims of volcanic effect on temperature. If they are so large as to claim 0.5C drop, such as where?

    Then consider why this effect seems so important. It’s about explaining away why there is no continuous AGW ramp up.

  3. http://expianetadidio.blogspot.it/2013/09/un-mondo-sconosciuto-sotto-un-sole.html
    During the Great Solar Minimum, increase the cosmic ray neutrons and consequently lead to an acceleration of the radioactive decay inside the planet with greater volcanic and seismic activity.