«
Volcanic aerosols in the stratosphere absorb infrared radiation, thereby heating up the stratosphere, and changing the wind conditions subsequently,» said Dr. Matthew Toohey, atmospheric scientist at GEOMAR Helmholtz Centre for Ocean Research Kiel.
As a test of the models» annular sensitivity, the response to
volcanic aerosols in the stratosphere is calculated during the winter following five major tropical eruptions.
Not exact matches
Alcide di Sarra of La Sapienza University
in Rome and colleagues from an Italian - Danish team found that the
volcanic aerosol from Mount Pinatubo penetrated the Arctic
stratosphere in relatively thin layers, at altitudes below 16 kilometres.
To the contrary, as there is an inverse correlation between low cloud cover and solar irradiation, and solar /
volcanic have influences
in the
stratosphere, non-excisting for CO2 or human made
aerosols.
Spikes
in temperature are caused by major
volcanic events, which push sulfur dioxide and other
aerosols into the lower
stratosphere.
Thus the changes
in the
stratosphere are basically a function of the greenhouse gases, ozone levels and
volcanic aerosols there.
-LSB-...] following a major
volcanic eruption (emitting sulfate
aerosol in the
stratosphere).
You clearly agree that
volcanic activity results
in aerosols arriving up
in the
stratosphere.
Both sulphate
aerosols and CO2 have their influence
in the (lower) troposphere, while solar and
volcanic have their highest influence
in the
stratosphere, this is essential
in the discussion.
Since
aerosols last much longer
in the
stratosphere than they do
in the rainy troposphere, the amount of
aerosol - forming substance that would need to be injected into the
stratosphere annually is far less than what would be needed to give a similar cooling effect
in the troposphere, though so far as the stratospheric
aerosol burden goes, it would still be a bit like making the Earth a permanently
volcanic planet (think of a Pinatubo or two a year, forever).
After a large
volcanic eruption, the layer of sulfate
aerosols in the
stratosphere gets thicker, and we see,
in the historic record, that the Earth cools down
in response.
One driver of temperatures
in this region is the abundance and variability of ozone, but water vapor,
volcanic aerosols, and dynamical changes such as the Quasi - Biennial Oscillation (QBO) are also significant; anthropogenic increases
in other greenhouse gases such as carbon dioxide play a lesser but significant role
in the lower
stratosphere.
Some models include
volcanic effects by simply perturbing the incoming shortwave radiation at the top of the atmosphere, while others simulate explicitly the radiative effects of the
aerosols in the
stratosphere.
In fact, the major effect of significant volcanic eruptions is cooling due to the sulfate aerosols that they release (although in order to have a significant cooling effect, the eruption has to be large enough that it injects the aerosols into the stratosphere where they can stay around longer... and it apparently helps if the eruption is reasonably near to the equator
In fact, the major effect of significant
volcanic eruptions is cooling due to the sulfate
aerosols that they release (although
in order to have a significant cooling effect, the eruption has to be large enough that it injects the aerosols into the stratosphere where they can stay around longer... and it apparently helps if the eruption is reasonably near to the equator
in order to have a significant cooling effect, the eruption has to be large enough that it injects the
aerosols into the
stratosphere where they can stay around longer... and it apparently helps if the eruption is reasonably near to the equator).
«Since 1997, when Pinatubo's
aerosol settled out, the
stratosphere has been exceptionally clear... Half or more of the warming since 1995 may due to the lack of large
volcanic eruptions... That's about 0.13 °C... The remaining climate change is presumably caused by other forces, such as solar variability, El Nino, Atlantic AMO warming
in 1995, lower Albedo and maybe even a little greenhouse gas.»
Bourassa, A.E., A. Robock, et al. 2012: Large
volcanic aerosol load
in the
stratosphere linked to Asian monsoon transport.
I consider it as very likely that the 20 year trends will still be statistically significant also
in three, five or ten years from now, unless there is some strong
volcanic explosion that blows a lot of reflecting
aerosols in the
stratosphere causing a temporary temperature dip, or some other cause the effect of which is explainable within the framework of current knowledge about the climate system, but as event not really predictable.
Despite differences
in volcanic aerosol parameters employed, models computing the
aerosol radiative effects interactively yield tropical and global mean lower - stratospheric warmings that are fairly consistent with each other and with observations (Ramachandran et al., 2000; Hansen et al., 2002; Yang and Schlesinger, 2002; Stenchikov et al., 2004; Ramaswamy et al., 2006b); however, there is a considerable range
in the responses
in the polar
stratosphere and troposphere.
Aerosols from
volcanic eruptions do have a cooling effect once they reach the
stratosphere but the effect of high wind speed
in the upper atmosphere would rapidly disperse these, and any local effects would be very slight.
Bourassa, A. E., A. Robock, W. J. Randel, T. Deshler, L. A. Rieger, N. D. Lloyd, E. J. Llewellyn, and D. A. Degenstein, 2013: Response to Comments on «Large
volcanic aerosol load
in the
stratosphere linked to Asian monsoon transport».
Ridley and his colleagues also tracked the source of
aerosols in the lower
stratosphere from
volcanic eruptions during the 2000s.
Of course temperatures
in the troposphere is influenced by
volcanic aerosols in the troposphere and
stratosphere.
That is contradicted by climate models providing a very decent match to the observed cooling following a major
volcanic eruption (emitting sulfate
aerosol in the
stratosphere).
Here, the authors use satellite and aircraft data to investigate the radiative impact of
volcanic aerosols in the lowermost
stratosphere since the year 2000.
What does seem to be known is that
aerosols fall out of the lower atmosphere (as high as they can be launched with conventional bombs)
in days, and persist for less than 2 years when launched into the
stratosphere by a major
volcanic event like Pinatubo which was equivalent to several H bombs.
Volcanic eruptions emit sulfate aerosols via volcanic plumes, which may stay in the stratosphere for months to years, reflecting sunlight back into space, cooling the Earth's lower atmosphere or troposphere over a long
Volcanic eruptions emit sulfate
aerosols via
volcanic plumes, which may stay in the stratosphere for months to years, reflecting sunlight back into space, cooling the Earth's lower atmosphere or troposphere over a long
volcanic plumes, which may stay
in the
stratosphere for months to years, reflecting sunlight back into space, cooling the Earth's lower atmosphere or troposphere over a long time...