Sunlight reduction in large volcanic events

[mheslep]

Last night I watched the fun, if not reliable, history channel piece on volcanic eruptions large enough to significantly reduce sunlight. I'm curious. What's a rough order of magnitude of sunlight reduction expected from the various size of events? Some quick googling gives me:

• Small, Pinatubo size: blocked ~5% for some months, 1-2 per century
• Large, super volcano size: like the one in Yellowstone, blocks 90% for decades, ~ 1 per ~1,000,000 yrs, but also directly destroys all life on a majority of its continent, poisons the oceans.
• Medium, Krakatoa size: can't get a number here. Assume bounded between 5 and 90% reduction, reduced planetary temperature a few degrees for a couple years.

Sound reasonable? Anyone have some Krakatoa-scale numbers?

http://books.google.com/books?id=tSIa0VQn1NQC&pg=PA125&lpg=PA125&dq=super+volcano+sunlight+reduction&source=bl&ots=eFBsAyf8lx&sig=hLLGPDe7f4MXi5anRbyEU8ogB80&hl=en&ei=4HqlSc6iGaKBtwf2wOjTBA&sa=X&oi=book_result&resnum=9&ct=result
http://www.climate4you.com/ClimateAndVolcanoes.htm

 

[jwlm88]

Krakatoa was said to cause a year without a summer and cause abnormally high tides, as well as huge tsunamis. I couldn't find any hard numbers.

 

[Xnn]

Don't remember where I got the following from originally, but here is some history:

Kuawe (1452-1453) -- An underwater vulcano in the South Pacific. In Sweden, grain tithes fell to zero as crops failed; western U.S. bristlecone pines show frost damage; and the growth of European and Chinese trees was stunted in 1453–57. According to the history of the Ming Dynasty in China in the spring of 1453, "Nonstop snow damaged wheat crops." Later that year, as the dust obscured the sunlight, "Several feet of snow fell in six provinces; tens of thousands of people froze to death. "Early in 1454, "it snowed for 40 days south of the Yangtze River and countless died of cold and famine." Lakes and rivers were frozen, and the Yellow Sea was icebound out to 20 km from shore.

HUAYNAPUTINA (1600) -- A stratovolucano location in Peru. The explosion had effects on climate around the Northern Hemisphere, where 1601 was the coldest year in six centuries, leading to a famine in Russia that eventually lead to an estimated 2 million deaths. From 1600 to 1602, Switzerland, Latvia and Estonia had exceptionally cold winters. The wine harvest was late in 1601 in France, and in Peru and Germany wine production collapsed. Peach trees bloomed late in China, and Lake Suwa in Japan froze early. Sulfuric acid levels deposited in the Greenland ice cap are larger than that from Krakatau (1883).

LAKI (1783) -- The eastern U.S. recorded the lowest-ever winter average temperature in 1783-84, about 4.8 degree C below the 225-year average. Europe also experienced an abnormally severe winter. Benjamin Franklin suggested that these cold conditions resulted from the blocking out of sunlight by dust and gases created by the Iceland Laki eruption in 1783. The Laki eruption was the largest outpouring of basalt lava in historic times. Franklin's hypothesis is consistent with modern scientific theory, which suggests that large volumes of SO2 are the main culprit in haze-effect global cooling.

TAMBORA (1815) -- Thirtythree years later, in 1815, the eruption of Mt. Tambora, Indonesia, resulted in an extremely cold spring and summer in 1816, which became known as the year without a summer. The Tambora eruption is believed to be the largest of the last ten thousand years. New England and Europe were hit exceptionally hard. Snowfalls and frost occurred in June, July and August and all but the hardiest grains were destroyed. Destruction of the corn crop forced farmers to slaughter their animals. Soup kitchens were opened to feed the hungry. Sea ice migrated across Atlantic shipping lanes, and alpine glaciers advanced down mountain slopes to exceptionally low elevations.

KRAKATAU (1883) -- Eruption of the Indonesian volcano Krakatau in August 1883 generated twenty times the volume of tephra released by the 1980 eruption of Mt. St. Helens. Krakatau was the second largest eruption in history, dwarfed only by the eruption of neighboring Tambora in 1815 (see above). After the Krakatau eruption, average global temperatures fell by as much as 1.2 degrees Celsius. Weather patterns continued to be chaotic for years, and temperatures did not return to normal until 1888. Brilliant sunsets and prolonged twilights were due to the spread of aerosols throughout the stratosphere.

and here are some links:

http://www.tehrantimes.com/index_View.asp?code=185344

http://www.volcano.si.edu/world/find_eruptions.cfm

 

[Andre]

What's a rough order of magnitude of sunlight reduction expected from the various size of events?...
Large, super volcano size: like the one in Yellowstone, blocks 90% for decades.

What would be the logic for individual dust particles to settle slower when there are more?

 

[Gokul43201]

Fick's Law.

And I believe it's sulfur-based aerosols residing in the stratosphere (not dust particles) that are primarily involved in long-term (several months) modification of albedo following a volcanic eruption.

 

[Bystander]

What would be the logic for individual dust particles to settle slower when there are more?

Fick's Law.

(snip)

?! Aw --- please --- don't do this.

 

[Gokul43201]

I'm guessing you are asking me to be more clear (admittedly, my previous post was a terrible rush job).

If you model the dispersion of particles (of some chosen size range) as a 1D diffusion problem following an initial pulse (the volcanic event) that ejects $N_0$ particles into a small region, the concentration of particles at (x,t) looks something like:

$$n(x,t)=\frac{kN_0}{\sqrt{Dt}}exp(-x^2/Dt)$$

where D is the diffusivity and k is some constant that I haven't looked up.

The important thing is that the total number of particles in any region R=(-d,d) around the location of the pulse, at some time t depends on the total number of particles ejected in the initial pulse ( $\int_R n(x,t) dx \propto N_0$ ) and falls away with time like $N_0~erf(d/\sqrt{t})/\sqrt{t}$. From the form of the expression, one can guess that it is takes longer to reduce the number of particles in R to some chosen value when the $N_0$ is larger (since the time it takes to make some relative number, $N/N_0$ is a characteristic timescale of the system - and this is generally the case, even if the dispersion mechanism is not strictly diffusive).

And what determines the albedo is the total number of particles in R, not the number relative to the initial number. So to get back to Andre's question, it is actually because (for a fairly wide range of concentrations) the distribution of settling times (probability of a particle initially at height h having settled within time t) is essentially independent of the initial number of particles that the albedo at any successive time increases with the number of particles thrown up initially.

 

[Bystander]

(snip)So to get back to Andre's question, it is actually because (for a fairly wide range of concentrations) the distribution of settling times (probability of a particle initially at height h having settled within time t) is essentially independent of the initial number of particles (snip)

Not Fick's Law.

 

[Gokul43201]

Solving Fick's Laws tells you how the concentration of stuff varies with time, distance and the amount of stuff thrown up in the first place. If you know how this stuff affects the albedo, you can then figure out how the albedo varies as a function of these things.

 

[Astronuc]

Some measurements from Mauna Loa.

http://www.noaanews.noaa.gov/stories2006/images/mauna-loa-solar-radiation-1955-2008.jpg

The Mauna Loa observatory is one of ten sites that collects solar radiance data on a daily basis.
http://www.mlo.noaa.gov/livedata/mlosolar.html


Some earlier work: Volcanically Related Secular Trends in Atmospheric Transmission at Mauna Loa Observatory, Hawaii
BERNARD G. MENDONCA, KIRBY J. HANSON, and JOHN J. DELUISI
http://www.sciencemag.org/cgi/content/abstract/202/4367/513

Abstract:

Twenty years of atmospheric transmission data from Mauna Loa Observatory show secular decreases at irregular intervals. In addition, a regular annual variation is present during unperturbed as well as perturbed periods. These variations in transmission can be measured to a few tenths of a percent from the data record. Transient decreases in transmission are strongly correlated with explosive volcanic eruptions that inject effluent into the stratosphere. Recovery from these ejections takes as much as 8 years and the recovery curve is linear. Observations in 1977 at Mauna Loa show that, for the first time since the Mount Agung eruption in 1963, the atmospheric transmission of direct-incidence solar irradiation at Mauna Loa returned to values measured in 1958 to 1962.

 

[Xnn]

Interesting...

The level of solar energy transmitted since Mt Pintubo has not (as of ~2005) reached 100%. Levels prior to Feb 1963 were noticeably greater; nearly 100% and 100% was briefly exceeded only around 1977.

I wonder if it is from pollution?

 

[mheslep]

Some measurements from Mauna Loa.

http://www.noaanews.noaa.gov/stories2006/images/mauna-loa-solar-radiation-1955-2008.jpg

The Mauna Loa observatory is one of ten sites that collects solar radiance data on a daily basis.
http://www.mlo.noaa.gov/livedata/mlosolar.html


Some earlier work: Volcanically Related Secular Trends in Atmospheric Transmission at Mauna Loa Observatory, Hawaii
BERNARD G. MENDONCA, KIRBY J. HANSON, and JOHN J. DELUISI
http://www.sciencemag.org/cgi/content/abstract/202/4367/513

Abstract:

Thanks Astronuc, interesting links.

 

[Redbelly98]

Krakatoa was said to cause a year without a summer and cause abnormally high tides, as well as huge tsunamis. I couldn't find any hard numbers.

This is not at all my field. Is there a simple explanation why tides would increase from a volcanic eruption?

 

[granpa]

http://en.wikipedia.org/wiki/Climate_changes_of_535-536

 

[granpa]

This is not at all my field. Is there a simple explanation why tides would increase from a volcanic eruption?

real tides are complicated. they are more like standing waves than anything else. I suppose that krakatoas effect on the ocean immediately surrounding it was like the effect of hitting a bell with a hammer. it set up standing waves that continued to ring for some time.

http://www.coas.oregonstate.edu/research/po/research/tide/index.html

 

[Count Iblis]

Last night I watched the fun, if not reliable, history channel piece on volcanic eruptions large enough to significantly reduce sunlight. I'm curious. What's a rough order of magnitude of sunlight reduction expected from the various size of events? Some quick googling gives me:

• Small, Pinatubo size: blocked ~5% for some months, 1-2 per century
• Large, super volcano size: like the one in Yellowstone, blocks 90% for decades, ~ 1 per ~1,000,000 yrs, but also directly destroys all life on a majority of its continent, poisons the oceans.
• Medium, Krakatoa size: can't get a number here. Assume bounded between 5 and 90% reduction, reduced planetary temperature a few degrees for a couple years.

Sound reasonable? Anyone have some Krakatoa-scale numbers?

http://books.google.com/books?id=tSIa0VQn1NQC&pg=PA125&lpg=PA125&dq=super+volcano+sunlight+reduction&source=bl&ots=eFBsAyf8lx&sig=hLLGPDe7f4MXi5anRbyEU8ogB80&hl=en&ei=4HqlSc6iGaKBtwf2wOjTBA&sa=X&oi=book_result&resnum=9&ct=result
http://www.climate4you.com/ClimateAndVolcanoes.htm

You are confusing supervolcanoes with flood basalts. Supervolcanoes happen quite frequently on geological time scales. Life has adapted to it, although we humans would have difficulties dealing with such an event.

http://en.wikipedia.org/wiki/Flood_basalt" This could have led to poisoning of oceans and the atmosphere:

the Siberian Traps eruptions were bad enough in their own right, but because they occurred near coal beds and the continental shelf, they also triggered very large releases of carbon dioxide and methane. The resultant global warming may have caused perhaps the most severe anoxic event in the oceans' history: according to this theory, the oceans became so anoxic that anaerobic sulfur-reducing organisms dominated the chemistry of the oceans and caused massive emissions of toxic hydrogen sulfide.

 

[TVP45]

Alan Robock at Rutgers does some nice stuff on volcanic cooling. Here's a starting link
http://earthobservatory.nasa.gov/Features/Volcano/

 

[mheslep]

Last night I watched the fun, if not reliable, history channel piece on volcanic eruptions large enough to significantly reduce sunlight. I'm curious. What's a rough order of magnitude of sunlight reduction expected from the various size of events? Some quick googling gives me:

• Small, Pinatubo size: blocked ~5% for some months, 1-2 per century
• Large, super volcano size: like the one in Yellowstone, blocks 90% for decades, ~ 1 per ~1,000,000 yrs, but also directly destroys all life on a majority of its continent, poisons the oceans.
• Medium, Krakatoa size: can't get a number here. Assume bounded between 5 and 90% reduction, reduced planetary temperature a few degrees for a couple years.

Sound reasonable? Anyone have some Krakatoa-scale numbers?

http://books.google.com/books?id=tSIa0VQn1NQC&pg=PA125&lpg=PA125&dq=super+volcano+sunlight+reduction&source=bl&ots=eFBsAyf8lx&sig=hLLGPDe7f4MXi5anRbyEU8ogB80&hl=en&ei=4HqlSc6iGaKBtwf2wOjTBA&sa=X&oi=book_result&resnum=9&ct=result
http://www.climate4you.com/ClimateAndVolcanoes.htm

You are confusing supervolcanoes with flood basalts. Supervolcanoes happen quite frequently on geological time scales...

How so? I believe I just did not include flood basalts. I proposed supervolcanoes as 1/1m years which is indeed frequent by geologic time scales.

 

[Count Iblis]

How so? I believe I just did not include flood basalts. I proposed supervolcanoes as 1/1m years which is indeed frequent by geologic time scales.

The statement that it

...directly destroys all life on a majority of its continent, poisons the oceans

sounded a bit strong to me.

 

[mheslep]

The statement that it sounded a bit strong to me.

It appears to me that the footprint of these ash beds rises to that scale.
http://pubs.usgs.gov/fs/2005/3024/images/fs2005-3024_fig_12.jpg
-all three in the last couple million years.