Cosmic Rays Linked To Cloudy Days

[zavvy]

<b>Cosmic Rays Linked To Cloudy Days</b><br /><br />LINK<br /><br />IF YOU love to moan about cloudy grey weather, you now have something to blame: cosmic rays. These high-energy particles originate in outer space and in solar flares, and can have a small but significant effect on the weather, increasing the chances of an overcast day by nearly 20 per cent.<br /><br />Giles Harrison and David Stephenson from the University of Reading, UK, examined 50 years of solar radiation measurements from sites all over the country, enabling them to calculate daily changes in cloudiness. By comparing this data with neutron counts - a measure of cosmic ray activity - for the same period, the scientists have shown an unambiguous link between cosmic rays and clouds (Proceedings of the Royal Society A, DOI: 10.1098/rspa.2005.1628).<br /><br />"The odds of a cloudy day increase by around 20 per cent when the cosmic ray flux is high," says Harrison, amounting to a few extra days of cloudiness per year.<br /><br />When cosmic rays hit the atmosphere they produce charged particles which seem encourage the growth of cloud droplets. Compared with greenhouse gases the effect of cosmic rays on climate is small. But it could help explain some of the more mysterious changes in climate Earth has experienced in the past.<br /><br />From issue 2536 of New Scientist magazine, 30 January 2006, page 17<br />

 

[yevaud]

I'd already posted a response to this elsewhere, but I'll do so here.<br /><br />As a guess - presuming the causal link is correct - I wonder if the high-energy cosmic rays disturb supersaturated packets of air, resulting in their dumping all of their moisture abruptly.<br /><br />This is a phenomenon you see in very cold climates, such as Greenland and Antartica. A plane will land in what appears to be crisp, clear, still air. And in so doing, disturbs the supersaturated region of air. Result: an abrupt, blinding fog.<br /><br />Just an idle speculation now. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[zavvy]

Oh dear...is this a duplicate thread?<br /><br />I've often wondered what effect planes have on our weather system in general. I've seen radar of localised cloud and rain in cities close to major airports. Do you know if any research has been done on this?<br /><br />

 

[yevaud]

Oh no - I meant a similar thread at the 'Port, not here.<br /><br />Yes - it's an effect (which was one of my "specialities," such as it were) known as an "Urban Heat Island." It's due to the heat absorption/retention/emission characteristics of large cities.<br /><br />Likely when a plane takes off or lands, it's exhaust contain many ppm of various particulates that rain and fog can form around as a nucleus. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[mlorrey]

This is important news: given that Earth is between galactic arms, the interstellar radiation levels are lower now than when our solar system drifts into an arm. The lower the cosmic ray count, the less cloudiness, and global warming increases: less sunlight is reflected by the reduced cloudinesss. Cosmic ray rates are impacted by solar activity as well.<br /><br />Another thing to consider: events in the past can also exhibit climatic resonances into the future, as well as bounce back that goes beyond equilibrium points, such that warming after the Little Ice Age would exhibit a cyclic effect over time, due to the many feedback mechanisms, both positive and negative.

 

[silylene old]

So if the sun were within a dense galactic cluster, we could expect many cloudy days to the presumably higher flux of cosmic rays from the many nearby stars. Of course, this would be the least of our problems! <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>