Hello All, Budyko’s points – re tropospheric vvs stratospheric aerosol - reiterated by Govindasamy Bala (below), in response to Nathan Currier’s question (also below) are clearly valid vis-à-vis cooling via scattering of solar radiation and concomitant global cooling.
However, it does not follow that the effectiveness of stratospheric seeding is greater than that of the Marine Cloud Brightening (MCB) geo-eng technique, which involves the (tropospheric) seeding of marine stratocumulus clouds with sea-water aerosol, in order to increase their droplet number concentration, and therefore their albedo (with concomitant global cooling). Latham et al (2008) presented arguments indicating that the ratio of the rate of planetary radiative loss to required operational power is very large (in the range 10**5 to 10**7 according to the type of vessel used for the continuous spraying required). They pointed out that the main reason why this ratio is so high for MCB is that Nature provides the energy required for the increase of surface area of newly activated cloud droplets by 4 or 5 orders of magnitude as they ascend to cloud top and reflect sunlight. All Best, John. John Latham Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000 Email: [email protected] or [email protected] Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429 or (US-Cell) 303-882-0724 or (UK) 01928-730-002 http://www.mmm.ucar.edu/people/latham ________________________________________ From: [email protected] [[email protected]] on behalf of Govindasamy Bala [[email protected]] Sent: Friday, March 16, 2012 3:52 AM To: [email protected] Cc: geoengineering Subject: Re: [geo] tropospheric aerosol use "Climate changes" by Budyko, on page 244, discusses why tropospheric aerosols are not as effective as stratospheric aerosols for climate modification. 1) life time is only a couple of weeks 2) Particle size becomes too big quickly and hence not effective for scattering 3) Presence of clouds make them less effective 4) absorption by aerosols of near IR shortwave could partially cancel the cooling by scattering. Bala On Thu, Mar 15, 2012 at 9:53 PM, Nathan Currier <[email protected]<mailto:[email protected]>> wrote: Does anyone know of any published papers exploring the use of tropospheric aerosol use? cheers, Nathan -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]<mailto:[email protected]>. To unsubscribe from this group, send email to [email protected]<mailto:geoengineering%[email protected]>. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- Best wishes, ------------------------------------------------------------------- Dr. G. Bala Associate Professor Center for Atmospheric and Oceanic Sciences Indian Institute of Science Bangalore - 560 012 India Tel: +91 80 2293 3428 +91 80 2293 2075 Fax: +91 80 2360 0865 +91 80 2293 3425 Email: [email protected]<mailto:[email protected]> bala.gov<http://bala.gov>@gmail.com<http://gmail.com> Web:http://caos.iisc.ernet.in/faculty/gbala/gbala.html ------------------------------------------------------------------- -- 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. -- 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.
