Influence of cosmic rays on cloud droplet formation explored in a global climate model

Feb 12, 2013
Above the clouds.

A research team from the State University of New York-Albany and Pacific Northwest National Laboratory used a global atmospheric model to estimate that charged ions produced by cosmic rays in the atmosphere increase new atmospheric particles formed by a factor of ten when compared with particles formed by a corresponding neutral, non-charged, mechanism. Though cosmic rays ionization is important in forming aerosol particles and altering the make-up of clouds, the team determined that the changes during the solar cycle are insufficient to produce a measurable change in the Earth's energy balance.

It's not the stuff of Buck Rogers. Scientists want to know: do cosmic rays alter clouds and climate? Some studies show a connection between measured variations in cosmic radiation, such as coming from the sun's surface, and climate, but establishing a physical mechanism remains elusive. One proposed mechanism is a chain of events that form new particles which affect clouds. In this scenario, influences the concentration of ions in the atmosphere, which provokes new particles forming from the ions. Then, as the particles collide and condense on other gasses in the atmosphere, the new particles grow until they are large enough to form cloud droplets. Finally, the ' surface area is thus altered affecting the energy balance of the planet. Although all of these mechanisms are plausible, the scientists in this study tackled a key question: whether the variations during solar cycles are large enough to produce a measurable influence on climate. Their verdict: not so much.

For this study, researchers from SUNY-Albany and PNNL added an ion-mediated nucleation mechanism to a that already represented other mechanisms for new . In the model, they first compared the total nucleation rates, cloud droplet numbers and the Earth's energy balance calculated with and without the presence of ionization. Then, they simulated variations in those quantities using measured changes in cosmic rays during different phases of the eleven-year solar cycle. The average change in the global energy balance between the solar minimum and solar maximum was smaller than 0.06 Wm-2. This is more than ten times smaller than changes due to increases in carbon dioxide or resulting from human activity over the last one hundred years. 

The estimate of the solar cycle ionization effect on the Earth's energy balance is uncertain because of random variations in the simulated clouds. To isolate the cosmic signal from the noise of random cloud variations, the group will repeat the simulations but nudge the simulated winds toward the same winds in all simulations. Further research is also needed to reduce uncertainties in the model representation of key aerosol particle and aerosol-cloud interaction processes.

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More information: Yu, F. et al. Indirect Radiative Forcing by Ion-mediated Nucleation of Aerosol. Atmospheric Chemistry and Physics 12, 11451-11463. DOI:10.5194/acp-12-11451-2012.

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User comments : 11

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El_Nose
3 / 5 (1) Feb 12, 2013
I have a stupid question... someone explain to me how stupid it is...

So they ran a simulated 11yrs and it was over ten times smaller a change than a 100yr change of another cycle ...

so what happens when you multiply it by 9 because 9 X 11 == 99 yrs
nkalanaga
5 / 5 (3) Feb 12, 2013
Cycles don't add that way. Like a wave, each cycle has a peak and a trough, and the next cycle's peak starts from the current trough. So, if the variation is X% per cycle, that's the difference from peak to trough, not from the peak of one cycle to the peak of the next.

A good example is alternating current electricity, which varies from -X to X volts in each cycle, but the average voltage remains constant.
StarGazer2011
2.3 / 5 (7) Feb 12, 2013
models prove nothing, they are merely a second order theory which provide results for comparison with empirical measurement. These guys have only done half the work, waste of time.
And how on Earth can they just add a 'nucleation factor' for cloud formation to the model when nobody has ANY empirical evidence for how large the effect is or even if it actually exists? This is purely straw man pseudo-science.
GSwift7
3 / 5 (6) Feb 12, 2013
As of the time of this posting, the entire final version of the paper is available here (as opposed to the draft version you get if you follow the link above):

http://www.atmos-...2012.pdf

At least read the abstract, and introduction, then skip down to section 4 (results).

The actual paper is much more interesting than this news release. It's obvious that the story above was written by someone with an agenda, and not someone connected to the actual study.
VendicarE
2.3 / 5 (3) Feb 12, 2013
From the article GSwift links to above....

4 Summary and discussion

"Based on the present CAM5 simulation,
the 5-yr mean impacts of solar cycle induced changes in ionization rates on CCN and cloud forcing are small..." - Indirect radiative forcing by ion-mediated nucleation of aerosol
StarGazer2011
1 / 5 (3) Feb 12, 2013
Can somone parse this for me (from GSwift7 link)
"This leads to an increase of total shortwave
cloud radiative forcing (SWCF) by 3.67Wm−2 (more
negative) and longwave cloud forcing by 1.78Wm−2 (more
positive), with large spatial variations."

Its the 'more negative' but that has me guessing; it appears to say that clouds block more short wave radiation comming in than they block long wave going out. But they call both 'forcings' and theres no sign attached to the number which confuses me, just the slightly cryptic 'more negative' and 'more positive'.

Anyone know what this boils down to?
StarGazer2011
1 / 5 (2) Feb 12, 2013
Also can someone confirm that they are exploring the idea of ion-mediated nucleation (IMN) as an alternative explaination for creation of cloud nuclei to the 'traditional' H2SO4-H2O binary homogeneous nucleation (BHN)?
I'm getting that feeling from the passage:
"Our simulations show that, compared to globally
averaged results based on H2SO4-H2O binary homogeneous
nucleation (BHN), the presence of ionization (i.e., IMN)
halves H2SO4 column burden"

and would like someone with more knowledge (clearly not the writer of this ridiculous article) to confirm or correct:)

Thanks GSwift7 for posting the paper, quite an interesting read.
Caliban
3 / 5 (4) Feb 13, 2013
As of the time of this posting, the entire final version of the paper is available here (as opposed to the draft version you get if you follow the link above):

http://www.atmos-...2012.pdf

At least read the abstract, and introduction, then skip down to section 4 (results).

The actual paper is much more interesting than this news release. It's obvious that the story above was written by someone with an agenda, and not someone connected to the actual study.


Swifty-

That someone with an agenda wouldn't happen to be you, would it?

No, of course not. Everyone here knows that you are non-partisan, impartial, and objective.

"...to a fault", as it has been said.

StarGazer2011
1 / 5 (3) Feb 14, 2013
As of the time of this posting, the entire final version of the paper is available here (as opposed to the draft version you get if you follow the link above):

http://www.atmos-...2012.pdf

At least read the abstract, and introduction, then skip down to section 4 (results).

The actual paper is much more interesting than this news release. It's obvious that the story above was written by someone with an agenda, and not someone connected to the actual study.


Swifty-

That someone with an agenda wouldn't happen to be you, would it?

No, of course not. Everyone here knows that you are non-partisan, impartial, and objective.

"...to a fault", as it has been said.



what a pointless waste of electrons that comment was Caliban
Caliban
3 / 5 (4) Feb 14, 2013
As of the time of this posting, the entire final version of the paper is available here (as opposed to the draft version you get if you follow the link above):

http://www.atmos-...2012.pdf

At least read the abstract, and introduction, then skip down to section 4 (results).

The actual paper is much more interesting than this news release. It's obvious that the story above was written by someone with an agenda, and not someone connected to the actual study.


Swifty-

That someone with an agenda wouldn't happen to be you, would it?

No, of course not. Everyone here knows that you are non-partisan, impartial, and objective.

"...to a fault", as it has been said.



what a pointless waste of electrons that comment was Caliban


Hmmmm.

If it went over your head, just say so. I can probably make it more understandable for you, if you would like.

Claudius
1 / 5 (2) Feb 16, 2013
"It's only a model" (re: Camelot in Monty Python and the Holy Grail)