353 replies to this topic

[Boar Wrinklestorm]

Captain_Bobski, on 17 Dec 2008, 01:16 PM, said:

Since we're just (at this point!) going for a rough analogy of the climate system, should we assume that all major volcanic eruptions block out 50% of incoming solar radiation for a period of, say, 2 years? Just to see what happens to "a".

Do you have list of 'major' eruptions since 1700AD? (and their year/month)

Edited by VillagePlank, 17 December 2008 - 13:23 .

[Captain_Bobski]

VillagePlank, on 17 Dec 2008, 01:21 PM, said:

Do you have list of 'major' eruptions since 1700AD? (and their year/month)

Thanks to the wonderful Encarta, here's a list of every eruption that has been classed as "Major" since 1700:

Papandayan, Java - 1772
Laki, Iceland - 1783
Unzen, Japan - 1792
Tambora, Indonesia - 1815
Krakatau, Indonesia - 1883
Santa Maria, Guatemala - 1902
Pelee, Martinique - 1902
Taal, Philippines - 1911
Kelut, Java - 1919
Merapi, Indonesia - 1930
Rabaul, P. New Guinea - 1937
Lamington, PN Guinea - 1951
Hibok Hibok, Philippines - 1951
Agung, Indonesia - 1963
Mt St Helens, USA - 1980
El Chichon, Mexico - 1982
Nevado del Ruiz, Colombia - 1985
Lake Nyos, Cameroon - 1986
Pinatubo, Philippines - 1991-1996
Unzen, Japan - 1991
Mayon, Philippines - 1993

That's a bigger list than I was expecting! Is it worth assuming the same effect for all volcanoes? I presume there are many subtle levels of "Major", but it'll take a bit of digging to find out how Major each eruption was. Perhaps we should reduce their influence to 20% or 25%, so that their effect doesn't overwhelm the background data. It might also be worthwhile reducing the duration of their effect from 2 years to just one year and see what happens.

I leave it in your more-than-capable hands!



CB

PS - Unfortunately the Encarta page doesn't give months of each eruption. If we assume that they all took place in June...? Also, for the years with multiple eruptions (1902, 1951, 1991) we should add the effects, I guess, so two eruptions would, assuming 20% per volcano, block 40% of incoming solar radiation (or would the second eruption only block 20% or the remaining 80%, in which case the total would be 36% blockage...?)

As for Pinatubo, which is listed as occurring over a span of five years, what do you think best? 20% every year for 5 years, or a gradual rise and fall from, say, 10% up to 20% and back down again?



EDIT - I've just noticed that the list only goes up to 1993 - additionally there was a "major" eruption in Indonoseia in 2004 and one in Colombia in 2008. Other lists include eruptions of Vesuvius in 1906 and 1944 as well as several in Africa since 1800...sigh...I'm not sure what to do. Shall we stick with the main list, plus the two post-2000 eruptions?

Edited by Captain_Bobski, 17 December 2008 - 13:59 .

[Captain_Bobski]

Aha! It seems that the definition of "Major" in the list above is "more than 500 fatalities" and nothing to do with the actual size of the eruptions at all. A much smaller list, below, shows the largest eruptions in terms of volumetric output:

Tambora, Indonesia - 1815 (100 cubic km)
Krakatau, Indonesia - 1883 (18 cubic km)
Katmain, Alaska - 1912 (12 cubic km)
Pinatubo, Philippines - 1991 (10 cubic km)
Mt St Helens - 1980 (1 cubic km)

How do you want to handle the numbers - debris volume divided by two as a percentage of light blocked out, just as a ballpark figure which keeps eruption size proportionate?



CB

EDIT - Hold that thought - I'm working on another list based on the Volcanic Explosivity Index.

Sorry to mess you around - I've obviously come down with a bad case of the web forum equivalent of verbal diarrohea!

Edited by Captain_Bobski, 17 December 2008 - 14:16 .

[Captain_Bobski]

Okay - I'm back! I'll just do this quickly before everyone gets thoroughly sick of the sight of me!

Based on the Volcanic Explosivity Index, here's every eruption ranked 5 (over 1 cubic km), 6 (over 10 cubic km), and 7 (over 100 cubic km):

Mount Tarumae 1739 (VEI5)
Mount Agung 1963 (VEI5)
Mount St Helens 1980 (VEI5)
El Chichon 1982 (VEI5)
Mount Hudson 1991 (VEI5)
Mount Tarawera 1886 (VEI5)

Laki 1783 (VEI6)
Krakatoa 1883 (VEI6)
Santa Maria 1902 (VEI6)
Novarupta 1912 (VEI6)
Mount Pinatubo 1991 (VEI6)

Mount Tambora 1815 (VEI7)

In date order:

1739 (5)
1783 (6)
1815 (7)
1883 (6)
1886 (5)
1902 (6)
1912 (6)
1963 (5)
1980 (5)
1982 (5)
1991 (5)
1991 (6)

Roughly speaking, a VEI 6 eruption is 10 times bigger than a VEI 5 eruption, and a VEI 7 eruption is 10 times bigger than a VEI 6 eruption (and hence a VEI 7 is 100 times bigger than a VEI 5).

The effect of each eruption should mirror this, so maybe a VEI 5 should block out 10% of solar radiation, a VEI 6 should block 20% and a VEI 7 should block 40%. How does that sound?



CB

[Chris Knight]

Here's an Excel file based on Ice core SO₂ data, showing Northern, Tropical and Southern hemisphere eruption dates, from Marc Duran Prohom's PhD thesis, together with Mann et al's 1998 volcanic forcing data, references on the worksheets.  volcanodates1.xls   366K   121 downloads

Some large eruptions, like Mt St Helens, had virtually no climatic effect due to the lateral direction of the ash plume, rather than vertically upwards into the upper atmosphere, and relatively small amounts of sulphate aerosols emitted. Other eruptions like Laki had considerable duration of significant emissions compared to one-off explosive eruptions.

[Boar Wrinklestorm]

Chris Knight, on 17 Dec 2008, 09:12 PM, said:

Here's an Excel file based on Ice core SO₂ data, showing Northern, Tropical and Southern hemisphere eruption dates, from Marc Duran Prohom's PhD thesis, together with Mann et al's 1998 volcanic forcing data, references on the worksheets. volcanodates1.xls

Some large eruptions, like Mt St Helens, had virtually no climatic effect due to the lateral direction of the ash plume, rather than vertically upwards into the upper atmosphere, and relatively small amounts of sulphate aerosols emitted. Other eruptions like Laki had considerable duration of significant emissions compared to one-off explosive eruptions.

Thanks for that

[Boar Wrinklestorm]

I've integrated the volcanic data, and included the deviation from the mean of the entire CET set. Red line is CET deviation (x 100) and the volcanic data is multiplied by 0.65 to trim the numbers down a bit.



I suspect that the volcanic data will need have it's own memory (so combine the results of the sunspot leaky integrator, and the volanic leaky integrator) because I must presume that the effect a volcanic eruption has may last many years.

Any ideas for any further inclusions, please feel free to post

[Iceberg]

Why assume that a volcanic eruption will effect for many years.?

Some eruptions very major had very major effects , whilst some didn't, it depends on exactly where the volcano is, how high the plume, what the plume consisted of, how long the eruption went on for, whether the volcano is southern or northern hemi, whether the eruption occured in winter or summer etc..

[Boar Wrinklestorm]

Iceberg, on 16 Feb 2009, 04:38 PM, said:

Why assume that a volcanic eruption will effect for many years.?

Some eruptions very major had very major effects , whilst some didn't, it depends on exactly where the volcano is, how high the plume, what the plume consisted of, how long the eruption went on for, whether the volcano is southern or northern hemi, whether the eruption occured in winter or summer etc..

Don't suppose you've got that data to hand have you?

I've moved the date axis out of the way ....

[Iceberg]

No Sorry, but I've looked into this (briefly ! ).

And to be honest it was a complete nightmare to try and make head or tale of.

Some eruptions like pinatubo (Can't be arsed to spell it right !), had a net effect of -0.3C cooling over 12 months globally.

[Boar Wrinklestorm]

Iceberg, on 16 Feb 2009, 04:46 PM, said:

No Sorry, but I've looked into this (briefly ! ).

And to be honest it was a complete nightmare to try and make head or tale of.

Some eruptions like pinatubo (Can't be arsed to spell it right !), had a net effect of -0.3C cooling over 12 months globally.

Well, all I've done to plug in the volcanic data is to multiply the figure that was in Chris' spreadsheet, multiply it by 0.65 and deduct it from 'b'.

I almost fell of me chair ....

I suppose El Nino/La Nino is next .... anyone know where to get the data going back nearly two centuries (does it even exist?)

Edited by VillagePlank, 16 February 2009 - 17:05 .

[Solar Cycles]

VillagePlank, on 16 Feb 2009, 05:03 PM, said:

Well, all I've done to plug in the volcanic data is to multiply the figure that was in Chris' spreadsheet, multiply it by 0.65 and deduct it from 'b'.

I almost fell of me chair ....

I suppose El Nino/La Nino is next .... anyone know where to get the data going back nearly two centuries (does it even exist?)

I'm sure the US Army have data on this VP, good luck!

[Captain_Bobski]

Here's a link to PDO data going back to 1950:

http://www.cpc.ncep....ensoyears.shtml

Ideally we want more, of course, so I'll keep digging!



CB

[Captain_Bobski]

There may be more useful data here:

http://icoads.noaa.gov/products.html

Unfortunately you need to register, log in and then apply for access. I'll give it a go and see if I can get hold of the info.



CB

EDIT - is there anything you can use on this page? (goes back, I think, as far as 1882)

http://www.cpc.ncep....v/data/indices/

Edited by Captain_Bobski, 16 February 2009 - 19:50 .

[Solar Cycles]

Captain_Bobski, on 16 Feb 2009, 07:39 PM, said:

There may be more useful data here:

http://icoads.noaa.gov/products.html

Unfortunately you need to register, log in and then apply for access. I'll give it a go and see if I can get hold of the info.



CB

CB I'm sure the US. Army has a site regarding this, unfortunately I can't find anything on it now. Pretty sure I've seen data on there site regarding ENSO dating back over 200 years. Can you help?

[Captain_Bobski]

Solar Cycles, on 16 Feb 2009, 07:50 PM, said:

CB I'm sure the US. Army has a site regarding this, unfortunately I can't find anything on it now. Pretty sure I've seen data on there site regarding ENSO dating back over 200 years. Can you help?

I'll have a dig around and see what I can find.

(Note to US Army personnel - I am not talking about hacking into any servers or anything! )

There's so much PDO info around that I'm not sure what I'm looking for - is any indicator of the magnitude of oscillation useful? There's the PDO Index, Air pressure at various altitudes, air temperature, ocean temperature.... I'll see what I can do.



CB

[Captain_Bobski]

Ah-ha!

Found a graph of reconstructed PDO from 1661-1991. Followed a link to the source and found the data here:

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/tr...uctions/pdo.txt

This is annual data (1 data point per year) up to 1991, from 1992-present there is data in previously posted links.



CB

[Chris Knight]

I don't have a lot to say except , and why not send it to WUWT (on the basis that they get lots of traffic) for further comment?

[Iceberg]

CB for the life of me I can't find the post up put up saying that the extra heat is in the air.(you made it yesterday), I was going to look at it and respond. Sorry probably an early morning moment.

Am I right in saying that we have a bucket half full with water with a drip-drip in and a drip drip out( A hole at the bottom), when solar is high etc the drip drip in is slight faster and the bucket fills a bit more than half way, when the drip drip in is lower i.e very low solar or lots of volcanos then the bucket starts to empty.

Replace the bucket with the earth and the half full water with a atmospheric heat content.

Simple I know but I am not very with it today.


Is the above a correct summery of the leaky interrigator and this is what VP has found could be responsible for recent warming ?.

[Boar Wrinklestorm]

Iceberg, on 17 Feb 2009, 07:24 AM, said:

CB for the life of me I can't find the post up put up saying that the extra heat is in the air.(you made it yesterday), I was going to look at it and respond. Sorry probably an early morning moment.

Am I right in saying that we have a bucket half full with water with a drip-drip in and a drip drip out( A hole at the bottom), when solar is high etc the drip drip in is slight faster and the bucket fills a bit more than half way, when the drip drip in is lower i.e very low solar or lots of volcanos then the bucket starts to empty.

Replace the bucket with the earth and the half full water with a atmospheric heat content.

The basic premise of leaky integrator is, and forget about climate for a minute, that outgoing quantities is regulated by existing quantities. What this means, in terms of a bucket, the more water you have in the bucket the higher the pressure of the water leaking (the faster it leaks) and the lower the amount of water in the bucket the lower the pressure (the slower it leaks)

I didn't invent it - it's used for modelling membrane potential of neurons in neural networks

Quote

Is the above a correct summery of the leaky interrigator and this is what VP has found could be responsible for recent warming ?.

I haven't found anything, I've simply demonstrated an alternative proposal of how we can model warming without recourse to CO2; I think that perhaps this is related to hysteresis - which, I think, the leaky integrator models nicely.

Chris Knight, on 16 Feb 2009, 10:57 PM, said:

I don't have a lot to say except , and why not send it to WUWT (on the basis that they get lots of traffic) for further comment?

Who?

Edited by VillagePlank, 17 February 2009 - 07:58 .