Andrew There is a list of packages at
http://atol.ucsd.edu/scatlib/scatterlib.htm You can download a wonderful free computing package for liquid drops written by Philip Laven from http://www.philiplaven.com/mieplot.htm See also: http://www.philiplaven.com/index1.html http://www.philiplaven.com/Publications.html Stephen Emeritus Professor of Engineering Design School of Engineering and Electronics University of Edinburgh Mayfield Road Edinburgh EH9 3JL Scotland tel +44 131 650 5704 fax +44 131 650 5702 Mobile 07795 203 195 [email protected] http://www.see.ed.ac.uk/~shs Andrew Lockley wrote: > Doesn't anyone have a computer simulation of light passing through > various aerosols, and the scattering that results? It would be great > to be able to show doctored photos of 'geoengineered sky' vs. 'normal > sky'. Robock pointed out these effects, but it seems that the > analysis has possibly been limited/flawed. > > A > > 2009/5/11 John Gorman <[email protected] <mailto:[email protected]>> > > I have to admit I hadnt thought of that aspect of aerosols in the > arctic. > > To Gregory Benfold -What do you think ? > > John Gorman > > ----- Original Message ----- > *From:* Bonnelle Denis <mailto:[email protected]> > *To:* [email protected] <mailto:[email protected]> ; > [email protected] <mailto:[email protected]> ; > John Nissen <mailto:[email protected]> ; > [email protected] > <mailto:[email protected]> > *Sent:* Monday, May 11, 2009 9:42 AM > *Subject:* [geo] Re: Balancing the pros and cons of geoengineering > > Dear all, > > > > (please forgive me if the following geometrical arguments have > already been discussed). > > > > The positive feedback (albedo, methane, etc.) rationale for > focusing about the Arctic is doubtlessly great. But the > geometry is not very favorable, especially if very tangential > sun rays are concerned, which is more often the case near the > poles than near the equator. > > > > The most dramatic case is the one of the most tangential rays > which: 1 - without geoengineering - would have traveled > horizontally through the stratosphere, unharmed, and which: 2 > - would be diffracted by the silica, half upwards but also > half downwards, giving their heat to the earth. Seen from the > sun, the relevant cross-section is around 10 or 20 km (the > considered stratospheric layer's thickness) multiplied by 2000 > or 3000 km (the considered bow length). Such a result (several > 10,000 km²) is not negligible when compared to the whole > target cross-section (the same 2000 or 3000 km, multiplied by > 300 or 400 km which is the width, seen from the sun, of the > true useful target region). In addition, the effect in our > x0,000 km² region will be more intense, as the rays which > travel quite horizontally through the stratosphere will meet > much more silica than those which make a larger angle with the > horizontal. > > > > And even in the latter case (i.e., in all the target region, > but mainly for sun rays which will reach the atmosphere with a > quite small angle with the horizontal), an effect of the > silica will be to increase the proportion of such rays which > will be redirected towards the ground in a rather vertical > direction, instead of coming quite tangentially (the blue sky > will be brighter). Thus, various effects will have to be > considered: lesser absorption in various layers of the > atmosphere, lesser reflexion on the ocean surface, deeper > penetration into the ocean, etc. It doesn't seem clear to me, > whether such undesired effects will be lower than the desired > fact that half of such diffracted rays will be redirected > upwards, i.e. outwards of the earth climatic machine. > > > > Best regards, > > > > Denis Bonnelle. > > [email protected] > <mailto:[email protected]> > > > -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
